How to recap a tube amp. Is there a rule of the thumb for 'modern' amps like e.

How to recap a tube amp I have a Sound Valves amp & preamp bought new in the middle 1990's, alon TV MAN — 12:54 PM: HiFi (Chifi) tube amp build - but my own design. Recap the power section and got her ready for new tubes. Click to expand There are always caps in the audio path in the pre-amp, even on the DC amps As stated in the prevoius messages, you should read nearly nothing on the grid (with a good DMM like a Fluke 87 V, at least) if it is a preamp tube or a cathode bias power tube, and the correct bias voltage if it is a fixed bias power tube (with maybe a slight difference lower due to the influence of the DMM). From fly135: The 3 caps (may be 1 with 3 sections) that filter the power supply are the first and most likely to go bad. Replies 121 Views 2K. It's also not uncommon when restoring an item to just decide to recap the whole thing Greetings and welcome to my channel, which features videos about classic vintage guitar amplifiers and circuits, vintage jukeboxes, electronic equipment and devices, handmade steam engines, and This is a review and detailed measurements of the Bob Latino's take on Dyna ST-70 stereo tube amplifier. There's definately something broke on the amp, they generally are louder than that. Solid state amps typically run much cooler, so there is much less tendency to need the re-capping. Thing is, it was a friends amp and he was floored how bad the amp sounded with the new caps. Prices are $1-$3 each, so you can recap a stereo amp for $30-$50 or so. Well decided to bring some life back into this thing. I've recently had a tube amp virtually fully recapped. Listening to a good 33,3 LP with an Yamaha MC 9 cartridge, I will hear a large 3d soundstage, tube middle and top, and a deep bass. A guitar amp with worn and dried up electrolytics can: hummmmm, have less gain, sound dull and thin, can be troubled by ghost notes, Tube amps contain very high voltages and are dangerous to work on. 5 F&T 22uF-500V (Main & Decoupling Filters) 2 Tube Amp Doctor 16uF-475V (Main and Decoupling Filters) 6 Tube Amp Doctor 25uF-25V (Cathode Bypass) Observing the proper polarity, temporarily replace them with silicon diodes using an old tube base (with diodes soldered in place) or with diodes connected by clip leads. The negative bias must be more than the largest This video shows the restoration, repair, and testing of the Dynaco ST-70 stereo power amplifier. There were only 8 capacitors, so it really was pretty simple. C-3, A-100, RT-3, D-100 etc. g. Safer for Speakers. That has given me a little confidence to try a solid I'm a long time vintage 60s tube amp owner and I recently started working on my own components. This recapped one just didn't quite sound right until tonight when l hooked it up again. Our channel i Follow along with Brent as he dives into what happens when you amplifier protects. Sometimes the power supply caps can be kept when meauring OK in terms of leakage current The Recap kit is the same for either. These old amps were used in Public Address and even in driving phone lines many hundreds of miles away. 77 and 14. I read how most seem to think if you have a tube power amp, then you should use a tube pre with it so the complete chain is tube. If you want tube sound, get a tube amp. The second was the Sony 808es integrated amp. The vast majority of valves will show the type, manufacturer and tube socket – choose matching amplifier tubes of the same type from TubeAmpDoctor and let’s get on with the repair! Interesting how some or most of us do not even need a schematic to troubleshoot or rebuild an amplifier. I want to tie back into my earlier comment about how tube amp players dislike modelers mostly because there’s nothing moving air in Increased ESR (Equivalent Series Resistance) can gradually turn a capacitor into a resistor. For beginning the pics sure would help and get a system for organizing Recapping and retubing are two major service operations that come up when discussing vacuum tube audio amplifiers for musical instruments (guitar, bass, harmonica, keyboards, steel guitar, In this video we will show you how to take a old tube amp. as well as different price for the same type. Is there a rule of the thumb for 'modern' amps like e. You can also buy high-voltage caps from Mouser, Digikey, Newark, and other huge Truly, the worst audio mistake I ever made, getting rid of that. If you want to learn the theory, this is how to do it. OP. Relaunched in 2000, the Traynor brand has subsequently produced both reissues and highly regarded new models, including the YCV line of tube guitar combos and the Horse line Preamp and Amplifier Boards Need Rebuilding; The 22XX lines of Marantz share a lot of the same issues, mostly around old components dying in the phono, preamp and amplifier boards. SHOPSUB TO THE AMP PODCAST https://www. Balanced Audio Technology VK 80 tube Preamplifier. Your variac will prevent the Vintage Fender Amp Repair specializes in do-it-yourself repair, modification and upgrades, as well as vintage Fender amplifier schematics and layout diagrams. 5 A. The most common symptom of power tube failure is the blowing of fuses in the amp. 1. #amplifierrepair #audioLinks:https A reverse tube layout diagram for easy chassis to schematic reference the amplifier path, the radio path, and the multiplex subchassis. If it sounds good to you now and you want to check the caps and/or recap it, find someone that has a Good cap tester like a sencore LC102 103 etc. 95 ROCKOLA 404 & 408 Amp Tube Kit $295. EDIT: All the above apply to SS amps ONLY. If it still sounds great, tight bass, clear highs, I leave it alone. Short little video on common mistakes seen when recapping (replacing capacitors) vintage electronics. ) such as the power on output muting. Needless to say I am more than just a little intimidated by them, I am not a experienced repair person so I need all the help I can get. Switches will fail, tuner wheels will need to be lubricated, volume knobs get scratchy. Even if the soldering was perfect when it was new, heat and vibration take their toll. That as a recap, in most cases, and with most techs I’ve witnessed or seen, should not cost over $600, max. This amp seems to blow fuses when power is supplied, therefore endi Some amps let you change the amount of power hitting the tubes with a switch marked “Pentode/Triode” or with different watts ratings. OP . Don't take my word, do your own research, and please be What tools do I use? https://youtu. 1 source is “The Tube Store” Be careful tubes can run from $15 and as high as $400. The three transformers give it substantial weight The AO-28 tube pre-amp is found in the Hammond B-3 as well as several other models. One of the big reasons CJ tube amps/preamps sound so nice and relaxed is that the power to the audio circuits, and all the other audio circuit functions, is done with Sorry don't know that much about tube amps. Receiver, Pre-AMP, AMP functional analysis, troubleshooting, repair and restoration. When opened the casing, and looked at the caps, they are not bulging or leaking anything that. i spent 500 on it. then ill be in for almost 800 Then you can look at the amp in a different light and use the knowledge to check through the amp to see what need to be done and what not. I still have like 300mV of sawtooth wave on the rails. They loose their value over the time and put the amplifier circuit into high frequency oscillation which takes out the output transistors. The tube job is out of line. MC225 Vacuum Tube Amplifier. Our tube preamplifiers are made with no screws showing and no Another Fender Tube AMP on the bench, this time a perfect condition Fender Twin Reverb. The MC225 has on one chassis two 25 watt power amplifiers. It's rare to see a vintage amp without at least a few cracked connections. I have zero experience other than soldering stained glass. If that cap is not replaceable by a film cap per my recommendation above because either it's too large in capacitance or won't fit due to space then use a As much as I love vintage tube test equipment, (Heathkit SG-8 generators, etc. "Have us Install" price includes parts and labor. Quantity: Quantity: ROCKOLA 429 Amp Cap Kit $69. eiraved; Jan 5, 2025; 5 6 7. Uncle Doug takes Schematics, Tube Amp Components, Architecture, and breaks it all down and in clear and easy language describes how everything works. I have a soldering station and variac, and I am chomping at the bit to get my pre recapped, but I here i go again. In this course, Terry from D Lab Amps takes you into his electrical repair shop, demonstrating creative, cost-saving electrical repairs from start to finish. Used in the Pro Amp AA763. Vacuum tube products can also have tired tubes, but transistors usually work, fail or make pops. One "free" benefit of using tube audio is that the warm-up of the tube would give a "natural" or "soft" wake-up with out needing to do it in the software. If there is an obvious problem with the output being different from one channel to the other, it may need a recap. McIntosh MC901. Second the electrolytic caps. In the next few days, I will be taking Uncle Doug's videos and Power supply upgrades to energy storage and regulation in tube amps are often audible as improved dynamics and bass definition. TIME TO FIX YOUR FENDER?! Got an old Tweed, Blonde, Brown, Blackface or Silverface Fender Tube Amplifier? Chances are it’s long overdue for a tune up! Like a car, your amp has parts that rupture, drift or wear out and need to be serviced or replaced in order to keep your amp functioning properly and performing/soundi I was given a tube amp by my Grandpa 10 years ago and am now ready to recap it for the first time. It would use external bookshelf speakers. Hey all! I've been pretty quiet on this one because I'd been having some "mystery" problems, which really left TV MAN — 12:29 PM The value of these caps is important. Vacuum Tube Amplifier LEGACY PRODUCT. This unit was bought used for around US $900. Description. That's the 450VDC 40uf, 20uf, & 20uf electrolyte capacitor. Sansui amps from 70s used to have notorious black flag caps (polystyrene). One of the amps i plan to recap have some cracked resistors (just 2-3 of them), and another amp has some burned ones (or at least they look burned). ) Year of Manufacture – The serial # is stamped into the rear panel & you can click this to date the amp 2. Forums. I replaced mine with 716P's and thought the amp sounded much better afterwards. Home. According to Gibson history buff Bjorn Anger, ``Gibson ledgers keeps records of Kalamazoo #1 and #2 amps being shipped from 1965. Especially if there isnt a bias needing adjusted. It was the last jukebox made to offer a tube amplifier. If you are new to recapping vintage tube gear, I recommend First, let's define "recap. I've been looking at Panasonics as candidates for a tube amp recap project down the road, and they're particularly appealing to me for their high capacitance in a small package. " Back in the nineties, when "how-to" articles began appearing in Vintage Guitar magazine, recapping meant just that - replacing every single capacitor in the amp. " I've repaired many 70s-era amps and have never seen one whose problems were caused by bad caps. If you own vintage audio equipment is it worth it to recap? Often times, the recapping is more expensive than newer audio equipment. But when powering on, the sound is a bit crackling and popping for about 5 minutes, and it seems OK for the rest of the day. IME the typical ’half life’ of caps in a tube amp is about 20 years. A tube amp, short for “vacuum tube amplifier,” is an electronic amplifier. every 2. This is a bedrock I started simply by recapping a tube amp from a motorola console. Contains the following capacitors, used as Line transformers, aka: input transformers, were intended to match the input impedance of the amp to the driving signal line in use. This video covers how amplifier protection circuits work, and how to troubleshoot amplifiers that are stuck in protection. What can cause protection, how to identify protection, and some basic trou Stereo Vacuum Tube Power Amplifier (1961) add a review. When to recap Your amp/preamp/integrated/receiver sounds dull, lifeless or lacks impact. So changing them makes sense. Roger Russell was a McIntosh design engineer for over 20 years. It is not a panacea or cure all. Sobering article on tube amp voltages. Used vintage solid state gear is a very workable, fun compromise. Let’s start at the beginning. GET DROP 2 AT HTTPS://AMP. The inside of the amp is extremely clean; it appears as though the amp has been very seldom if ever used. Downloads. The possible exception are the high-value ceramic coupling caps used, e. Hi, I;ve got a few old Pioneer amps (SA-*20 ones) I just wondered as some sound different to others, could this be a sign that the capacitors are starting to pack up? What are the signs in terms of sound quality that the capacitors or In a 40 year old (tube) amp, the coupling capacitors are somwhere between suspect and muerto. eddiep1966 Posts: 16 Joined: Fri Aug 06, 2021 12:14 am. I know Jim McShane and a couple others use Panasonic caps in power supply kits, but last I looked, they (Panasonic) make about six or eight different series of can caps I am intrigued by this amp as it has been getting rave reviews. The high voltage makes the day and night difference. You do want to change filter caps of tube amps. Get THE MOST out of your vintage Fender amplifier! In-shop repair service for your Vintage Fender Amp! We would like to show you a description here but the site won’t allow us. One of the most copied amplifier designs in history and it We do not currently have a recap kit for the 68 Custom Vibrolux Reverb amp that is silverface with a drip edge. Top Premium Capacitor Set Shown: Click on photo for larger view: Fender™ Electrolytic Filter Capacitor Kit 3. S. Sorr Well-known member. Upon receiving the p Retro Repair Guy restores an old audio Power Amplifier from 1977. this drown out all the other worries people have already. Quantity: Quantity: ROCKOLA 404 & 408 Amp Cap Kit $69. 00 Amp Maintenance. While I really doubt that you could hear this warm-up difference, you might be able to Recap. , in the EICO HF-81. HA. Don't touch it unless you take precautions. Its a little longer in solid state stuff because there is less heat but that might mean only 5 extra years. The larger they are, the better the amplifier output transistors will couple to the speakers at low frequencies. As it was an amplifier the customer was actively using and gigging, it needed to be tip top. Share . For vintage Fender™ amps (NOT Reissues!) from the original blackface and silverface eras which have two power tubes (6L6 or 6V6). The customer request for audio grade capacitors. Available in Top Premium (F&T/Sprague Atom), Pro (Tube Amp Doctor), Standard OEM (Illinois Capacitor), or Basic MOD ™ Electronics (MOD ™ Capacitors). While the second school of thought will say replace only what is absolutely The power supply, preamp, amplifier, filter stages, all have to work well together and changing one has the potential for unintended consequences in another. 95 ROCKOLA 414 & 418 Amp Tube Kit $295. Many, many solid-state amps that are all worthy. To recap: playing into a cranked amp doesn’t just shift the available spectrum of loudness upward. That is the first to do. A tube amp, even an unplugged tube amp, stores enough electrical energy in it's capacitors to kill you! YES, KILL YOU. This is what gives this amp its unmistakable clean, crisp tone that breaks up beautifully at higher volumes. Designed in the fifties, this pre-amp remained in production until 1975. Of course, there are thanks for the replies guys - i think your thoughts on bad coupling caps are correct. Most amps use 1,000 microfarads, and this is good enough, although I will sometimes go to 2,200 microfarads, especially if the amp is used with 4-ohm speakers. This was my second project, after recapping my Fisher KX-100. In this video, I discuss two types of hum found in tube amplifiers, how to easily differentiate between the causes, and how to effectively remedy the situati Introducing the Fender Frontman 20G. The Hitachi HA-330 OCL type amp. With over 35 years of experience in electronics manufacturing and a lifetime of tinkering, Let’s Recap Vintage HIFI is a service workshop dedicated to evaluating, restoring & repairing your vintage electronics. Unless something is wrong with the amps recapping is generally a waste of time and there's a chance to damage something in the process. Learn how to make a variety of electrical repairs to vintage audio electronics, including tube amps, amp cabinets, and speakers. Reasons to recap are discussed, as well as horror stories of recaps gone A customer sent this Sansui AU-101for re-cap. ) Photos of the circuit board - An amp manufactured in 1970 will be hand-wired & with photos one can determine I'm not electronician but i've been learning by myself how to service all my vintage guitar tube amps (i have about 40 ! ) and to build some high end repros of several of these vintage guitar tube amps from the 50's to the 70's (Marshall plexi, Fender tweed , blond and black face, hiwatt, vox , supro & valco & co etc) using only high actual When to recap a recap? I'd kinda wondered the same to some degree. You can easily increase the capacitance to give the amp more filtering. i measured the dc voltage at pin 2 (grid) and did find dc on both channels (varied between startups, but would sit somewhere between 2. If you want to learn mor If you decide to recap a amp/receiver your digital camera is your friend. Yorkville ceased tube amplifier production in 1980 and retired the Traynor brand entirely in the early ‘90s to focus on sound systems and other high-end audio products. Learn how to replace parts and perform troubleshooting, and It seems that many modern tube amps convey a much brighter harmonic tapestry, a case in point being Linear Tube Audio’s ZOTL40, a David Berning design I happened to review. Learn where the high voltage is and how long it stays on the circuits after the amp is shut down. Easy step by step comm ROCKOLA 1484 & 1494 Amp Tube Kit $199. Understand which caps should be replaced, what the top brands are, Making sure your amp is biased properly for the tubes you are using is a key to making them last longer. Includes tube amp bias, cleaning potentiometers, cleaning and re-tensioning tube sockets, diagnose and advise on general operation, specifications, condition of all tubes, power supply and failed or missing components. The amp was sold a little while after for fear of the originals not lasting much longer. In addition to use as a stereo amplifier, the flexibility of the MC225 permits it to be used as a monophonic amplifier that delivers 50 watts, or as two separate 25 watt amplifiers with each channel amplifying Haha, umm motors and tranny’s don’t cost less than $10 and take maybe 15 minutes. To varying degrees, we know that these amps sound different from each other—and we might even know some basic specs, like what kind of tubes different models use, and maybe some details about stock speakers. It then walks through the selec There's nothing like tossing yourself into the fire to get going on something like guitar amplifier & radio repair. Preamp Tube Bias Resistors (cathode) Matched Power Tube Resistors; In-Shop Repairs 135W / 70W Ultralinear Recap Kits. Regular price $12 Servicing the Hammond B-2/C-2 Type Pre-Amp; Servicing the Hammond B-3 Type Pre-Amp; Leslie Speaker Menu Toggle. , vellum paper burns, etd How can one decide to recap an amp when there's no obvious problems yet? (e. Tired caps can cause symptoms like Is the amp going out on the road or just sitting in a collection? Is it a pre-war Gibson EH-100 or a JCM 800? The goal is to optimize that particular amp for the customer. New posts Search forums Subscribe. I'm just curious wether it takes a while for everything to settle down and sound it's best. Manufactured 1961 - 1967; 25 Watts x 2 Channels, 50 Watts x 1 Channel; Vacuum Tube; Print this page. May 13, 2012 #3 Tube amps are a lovely source of heat, and thus we see many caps from tube amps that get tired and need replacing. I had recapped many speaker crossovers and computer motherboards which was very straightforward so I was confident that I could do it. Quantity: Quantity: ROCKOLA 414 & 418 Amp Cap Kit $69. I use a pair of the earliest, MC50 monoblocs, as well as a refurb'd MC2105. If it’s a speaker I am intimately familiar with I’ll go ahead and recap. I only recap any old tube stuff that has the original paper and electrolytic capacitors that are way old or dried up. I heard from another member that there exists a step by step pictorial on how to recap a tube amp. Some people will swear that their amp didn't sound as good after a recap- just read the aforementioned thread. The polished stainless steal case looks very nice. It did not have any problems, but I thought it might sound better and last longer. 00 10 Year Amp Maintenance tube units can be easier due to simpler designs and less parts count (I have no problems looking at p2p/pcb tube amps but I scream with fear when I open up a SMD motherboard that needs specialized tools just to remove/swap/fix components and that's if I can isolate bad SMD parts and I can't see anything without a scanning electron microscope) Tube amps are transformer coupled, and by definition (and my measurements) have zero DC offset. I would just go new, Go to a reputable tube supplier and buy tubes, or negotiate with the tech for a better price. 49 v dc on one channel and 4. User Documents; MC225 Owner's Manual (1. If your Fisher receiver experiences any of the above symptoms, this kit can correct them. But some caps have known problems and may not last There is a 12V powered SE stereo tube amp sold on ebay (can't find link at the moment) that I would use for the amplifier. The Berning sounds faster, is more aggressive in dishing out transients, and shifts the presentation slightly forward. The schematic below shows a tube heater power supply in an Audio Research D51 amplifier. The first school will say to replace everything since you have it opened and already working on the board sometimes just the simple handling of the board outside the case and the introduction of heat on the board may actually speed along some other failures that need to be addressed. THE BEST source for your vintage Fender needs. I'll focus first on power supply. It also squashes the available dynamic range, making the quieter parts louder and the louder parts quieter. The filter caps literally store & I really like the tube(y) sound of this amp, it is very transparent and demanding of the source. However, most tube amps have four valves instead of just one. The second Twin shows that This short video explores how to select a replacement radial capacitor based on capacity, working voltage, and physical size. Good luck! That one I did recap but all the caps that came off of it tested fine bar one or two. I’ve changed caps in an amp only for the amp to sound like absolute shit. The circuitry isn't doing anything different in steady-state distortion, as measured on the test bench, but its transient performance will very probably improve. I certainly needed guidance early on. And, it remains fully functional and serviceable today. 5 to 3 years all output goes $300 and smaller tube last longer but still needed change every 5 to 6 years another $300. When a transistor amplifier has a shorted transistor or other problem, your speaker will blow unless their cables are fused. See the complete model cross reference. But I love them and REALLY wanna learn more about them! Reply. 95 I was 20 years old in 2011 and I decided it was a good idea to recap my Yamaha M-4 Power Amplifier. We will bill you return shipping upon installation completion and which will be comparable to the cost of shipping it in. Krell Chorus 5200 XD. Naturally, not all Fisher problems can be corrected with this kit, but consider this kit the basic starting point in I recently re-capped my 1971 Marshall JMP50 (a guitar amp) with F&T electrolytics as I was afraid of the old Hunts 50x50uF electrolytics exploding and taking out the Output Transformer. If you must go through the pains I'd suggest to learn how to make basic measurements of the amp first and capture the baseline performance, and then once done get another set of measurements and compare if anything Variable Bias Amplifier $100. Servicing these amps isn't like servicing a typical Fender/Marshall amp---- your 120 has the infamous active Mk4 preamp that is known to have noise problems even when working properly---- these amps can be frustrating to work on because when the usual "amp service" (cap job, tubes, bias, cleaning pots/jacks/tube sockets/etc) has been done My general rule is if the amp / receiver is older than 50 years, it needs a recap. Obviously, it had been re-capped before. its a lovely sounding amp to start with, but maybe a bit syrupy and lead footed. On some occasions after This implies that caps in the power supply are the first to go if the unit is 15-20+ years old or older. i bought an adcom gfa 5500. It brings together familiar Fender cosmetics and “best-in-class” sound quality that fits every player’s budget. ); and did employ them for quite a while, I found myself spending nearly as much time fixing the test equipment as I did fixing broken radios, which was a problem here given the volume of radio repair work. Regular price $79 00 $79. Moderators: pompeiisneaks, Colossal. $200. However it might take a half hour of warm-up for the bias circuits to finalize. I think they just got used to the warm fuzzy sound, or boomy bass that robisme cites, and weren't ready for Recap. Tired caps can cause symptoms like this. There is an assumption that you can increase the size of the PS filter caps and this will increase your amplifier's power output. Basic recap and restore BOM parts list on Kenwood KA-4002 integrated amp (2017) by @dlucy Recapped and Upgraded Kenwood KA-4002 (2014) by @eizner23 Real-world mods for modest quasi-complimentary amps (Sansui 661 and Kenwood KA The best of the old and new tube technology. Is more expensive cap always better than The Kalamazoo amps covered in this guide and best known by electric guitar and harp (harmonica) players are the ones made "twenty years later" - in the mid to late 1960s. The upper frequencies in comparison to the better tube amps out there currently is also not extended and I always noted a glare I couldn't completely eliminate. If a speaker has even decent caps and sounds good I’ll leave it alone unless it’s a specific request to recap or I just feel like recapping for the fun of it. General discussion area for tube amps. Vintage Most vintage Hifi users are placed in front of the dilemma: should I recap? And if yes, what should I do? We will try to give a few answers . Due to the way electrolytics are constructed and the high temperatures present in tube amps, electrolytics also have a limited lifetime. Proper Lead Dress - Take a look inside a boutique tube amp and you will see all the wires carefully twisted and placed for greatest WARNING: Do not try to repair an amplifier or its associated power supply if you lack experience working with high voltage as it will kill you; the electroly It is common practice for amp techs to replace all of the electrolytic capacitors in an amp every ten years or so. youtube. YMMV, as they say. But I have many old amps here, some from the fifties running at high voltages like 500volts, for which it's hard to find new caps. Leslie Patent Drawings; Servicing the Leslie Motors; The first voltage comes off the rectifier which may be a tube circuit on very old models or more likely a bridge rectifier made out of four diodes. Cap Can Hole Cover. Didn’t hear much difference after the recap. They can also dry up & malfunction (especially when left unused). I have bunch of audio What is a Tube Amp. After a while us techs memorizes the tube pins on a socket for most tube types and Amplifier Bias . Joined May 10, 2008 Had restored many vintage equipment like vacuum tube and transistor pre and power amps as well tuners and musical amps. It’s probably safest to switch the power supply only when the amp is all the way off. $300 sounds like a fair price for a recap job. These caps wear out & drift over time. When a vacuum tube is amplifying signals, the level of negativity on its control grid is important. Recapping is replacing the electrolytic caps (electro­lytics). it will cost 245 for a recap kit. On '80s stuff, if the unit is working, I give the owner 3 options: leave as it is until it fails, recap only the power supply and power amp sections, and full recap of the unit. This applies to But if you have to move it around a lot you should consider the weight and size and the fact that it requires normal tube amp maintenance. The filter caps are shiny and the leads appear to have little to no wear. Fixed Bias Amplifier $120. 1/6. BOB I am wondering when would be the best time to recap my vintage solid state Kenwood amp. a few questions, maybe. For this vintage electronic repair, I had to replace all t Recap means, “put new capacitors into the power supply. You must have a verified phone number and physical address in order to post in the Audiogon Forums. Recap it and bring it back online. 4 MB) About; Products; Inspiration Gallery; Automotive; Marine; Shop; House of Sound; The Fender Deluxe Reverb Reissue is an all-tube combo beast, with dual 6V6 Groove power tubes, four 12AX7 preamp tubes, two 12AT7 preamp tubes, and one 5AR4 rectifier tube. It is common practice for amp techs to replace all of the electrolytic capacitors in an amp every ten years or so. Additionally, the hot temperatures inside a tube amp shorten their lifetime. Remember, tube amps can store up serious voltages, and messing with power supplies could shorten tube life. New posts New media New media comments New profile posts Latest activity. Learn how to select capacitors [caps] for recapping old computers and vintage electronics. The new ST-70 offers a middle-of-the-hall Many 1970’s stereo models do sound “warm, velvety, full and deep” but they do not truly replicate the unique sound of a tube amplifier. ” Our preamps work well with any power amp, whether it is a solid-state power amplifier or a tube power amp, because we have exceptionally low output impedance and our other parameters are very much middle of the road. Compared to a PVM's main board which is under the tube and connected to the anode cap, it shouldn't be too bad to pull out the cards / modules and work from there. Many amps need to be re-biased when their output tubes are replaced; a job for a pro, unless you have the skills to do so safely yourself. Spend $30 and recap it. It will have more power available when your tubes need it. I own over14 tube amps and have worked with HUNDREDS over the yrs. a NAD Teardown Lab - Changing capacitors recapping circuit boardsEver needed to recap an old console or pcb? Here is how you do it, easy and cheap! #retrogamingCom What I do: I recap every piece from the '60 or older, because safety reasons. Shut it down with the standby switch still on should help kill the volts, but even then Check for high voltage before sticking your hands back down in there. The RIAA amp is a very large PCB, on the right hand side, standing upright next to the coolingfins. Today at 4:45 PM. However, today you'd definitely need to recap the amplifier and the price of the #7868 tubes used in this amplifier are getting very expensive. Due to the way electrolytis are constructed and the high temperatures present in tube amps, electrolytics also have a limited lifetime. . A tube amp with worn and dried up electrolytics can: hummmmm, have less This model was available with either a transistor amplifier or a tube amplifier. On old tube amps often the coupling capacitors (foil type) are electrical leaky. This would include vintage stereos, radios, equipment, 2 watts on the speaker from a 100 w Allen organ amp, a Hammond organ that sounded like a soft kazoo with no string bass or attack instead of the premium product shipped in 1967 (77 capacitors in that), a ST70 that went "polite" about every 7 years. Over-Fusing: To protect the power transformer while reforming, replace the usual 2 or 3 amp fuse with a very low value, such as 0. Save for vacuum tube amps and amps that have been sitting on the shelf, break-in would be a matter of seconds. com/channel/UC51ypdbMnEyRb9f9MCOg_Vg?sub_confirmation=1AMP AMP AMP AMP📸 Follow us o Hi! I have some amplifier recaps planned, and while checking over values of caps, i noticed something. 2 v dc on the other - either channel the voltage kept gradually creeping up) Famous tube amps from companies like Fender, Marshall, Vox, and others have come to define the sound of virtually all electric-guitar music. How do you start up an old tube amp that hasn't been used for probably 10 years and you don't have a Variac? Can you safely do it with a light bulb current limiter? I have an all original 1965 Fender Showman that a relative gave me and after physical inspection and a lot of cleaning up I'm ready to fire it up but I'm concerned that the filter The power supply and amplifier sections tend to go bad first because of heat. add clips to the amp/radio inputs, attach speakers and now you can clip to a test point to trace audio signals. His work really creates the basis of a practical primer of how tube amps work. someone here provided information that it is out of spec to due cap age. Capacitors can also “leak” DC current and voltage – throwing bias off in different parts of the circuit which can affect the performance of tube and transistor circuits. Mostly you find these in tube amps that are built in 3D. I've been chopping and changing between 4 different amps and a couple of sets of speakers. Use your head and moderate i dont believe in the higher priced 1’s delivering better sound. Other sections start to go bad after the power section Reduced tube life, sure. And that's exactly what I did in this, my The first step when planning to recap a component is to attempt to get the schematic or service manual. I would almost always replace them prophylactically. These caps wear out & drift over time. Contact for a quote. Joined Sep 16, 2005 Messages 277 Location Australia. Available in Top Premium (F&T/Sprague Atom), Pro Learn how to repair or restore a piece of vintage audio equipment. I believe (the kit?) costs US $1,430. Harman Kardon HK-20 EL84 Mono The amp sections turn out to be the most reliable, but moving parts, large power supplies, RF sections ( and fancy high speed circuits prone to self-immolate ) turn to need some love by now. I saw a few good videos on soldering from voultar - look up the PC engine duo recap video to see surface mount and through hole caps. A single 22-inch Jensen speaker does the heavy lifting and is the perfect The best recap difference for the good i have had was my AU-505 Not my recapped AU-9500 or AU-11000A with most Slimic II Not that the AU-505 was bad before, but after, it is the most impressive difference i have had. How to choose capacitors and intstall them in tube radios is explained in non-technical language. Output tube replacement requires more thought than preamp tubes. Recapping is replacing all the electrolytic caps (electro­lytics). 400V should be sufficient in a lower powered amp. I'm just a hobbyist. Only a look at the defective valve will help here. The first Twin illustrates just how much use and abuse a well-designed tube amp of that era can withstand and still operate. However, while tube amps sound great, they are more fragile and require more maintenance than 1. after I figured it cost that much I sold them. also, if you have old portable radios, amps, and speakers around these make very good test equipment. You can purchase ANY tube you need online just type in your tube # and many choices will come up. donnyjj2005 Active member. There are no records of Kalamazoo amps after Good speakers for tube amps (I have a Blackbird in a VOX) fat low end and sparkly highs with good dynamics and harmonic overtones when driven. I don't have much of an idea how to date my amplifier, but based on the looks of the cabinet, I'd say it is maybe a mid to late 1960's model. It amplifies the signal from an electric guitar and uses the vacuum tubes, or valves as they’re often Recap/restore the preamp with contemporary stock components Upgrade with modern, more expensive hi-fi components (Teflon caps, etc. its lacking ass-end. I was smart enough to mark the old caps and was able to put them back in. I owned 3 tube amp, and loved the sounds, but sold them because it was costing me the same for tubes every 10 year then the amp was worth. That goes for tube or SS gear. Fender™ Power Tube Socket Replacement Kits for Vintage Blackface & Silverface (60s & 70s) Click on photo for larger view: Fender™ Vintage Amp (60s Blackface and 70s Silverface) Power Tube Socket replacement kit. Tube amps with one power tube are always Class A because the tube must always handle the full sine wave from the input signal. 00. Filter caps usually goes with a big bang, it's just matter of time. Larger values "can" give you amp a better Bass response. 11 posts • Page 1 of 1. Notice the transformer windings Carefully inspecting the soldering is one of the most important thing you can do to a vintage amp. As you said, why replace them unless there is a tl;dr if the amp seems to work fine, it is fine. A place for tone seekers to discuss tube amps and analog goodies. This can cause serious damage to your amplifier. Mains voltage on the chassis--sure, depending on the design of the radio, line cord and cap. The starting value (before any signal is applied) is called the "bias" value. The four tubes are placed in two sets of A-B operation tubes so that they add power to each “half” of the sine wave. If you find an orange jacketed cap in a 70's Kenwood it can be identified as a low leak cap. Subscriber. Mr Boochie. Specifically, the bias circuit in a tube power amp and the coupling caps leading into the last stage pretty much qualify as candidates here. 4. B - Voltage rating Choose a capacitor which has at least the voltage rating of the one you are replacing. Scroll down the page and is listed by amp, tuner, etc. No need to recap or do any other surgery unless you want to, in which case, sure go ahead! In the immortal words of Red Green, "if it ain't broke, you ain't tryin'. When a tube amp has a problem, the output transformers saves the speaker from shorted output tubes. As long as amps don't use regulated supply, even high end amps like Krell, Bryston, Threshold and the like will have hundreds of mV of sawtooth wave on the rails. Watch as Need advice on how to select "good" or "best" capacitors to recap my amp. 25 or 0. To "recap" a typical tube radio you will need two or three electrolytic capacitors, one or two line filter interference suppression safety capacitors and about I bought this old jukebox amp because it looked like a relatively cheap way to get a relatively powerful tube amp: 20 watts per channel. I suspect Hyperion is referring to plate swings in tube amplifiers, not solid state which Replacing capacitors is no substitute for repair. Chances are good that a recap will help here. But didn't find much difference to justify the pain and cost of recap. be/MLK649c1_fM1:02 - Disassembly/Removal3:55 - How To Spec and Find Replacement Caps7:16 - Reassembly/Installation12:42 - I was wondering how you would know its time for a recap on your amp. no bulging caps, no real sound issues) I can assume that the sound could change very gradually over time, making detecting the need for recapping harder. Replacing capacitors seems straight foreword enough until I came across the Multi Cap Cans inside the unit. Even when it sounds fine and the caps are not bulging or leaking. Have a portable cd player with a headphone cable plugged in - the other end strip the mini-plug and attach clips now you If you are new to restoring antique tube radios here are some useful CAPACITOR TIPS. When the time comes to change the power tubes you will definitely know as they generally only have two states, working or not working. The capacitors and transistors in these units are approaching 50 years old and often need to be replaced. See the section on DISCHARGE THOSE CAPS!!!!! I'm not a tube repair technician, or an expert electrician. Measure Low leakage caps are frequently found in the tone amp, filtering, preamp, and phono amp circuits . Except for the Pilot Light and tubes, that amp is all stock so losing the OT would have killed its value. I was wondering if anyone had any suggestion on were to bias this thing Many guitarists prefer tube amps over solid-state amps because they have a well-rounded sound and much more power. for example a tube amplifier. Media. What's new. I have check at Mouser and found so many types such as " Low Leakage", "General Purpose", "Audio Grade". So my questions are: 1. One of the most common issues is a faulty phono preamp board. These applications use different wiring and impedances than what we find in consumer electronics. As with the tube gear, the older (say, pre-90, or so) amps and preamps benefit from a recap and tune-up. It will be money well spent! Chris Brown AK Subscriber. Covers receivers, preamplifiers, amplifiers, tuners and tape decks. My question is has anyone ever paired this little guy with a Dynaco ST-35? I am currently using a SS pre with it with awesome results. This discussion is designed to help owners do some basic troubleshooting and, we’ll get into some You normal amp will be lucky to have 50,000uF. It uses a lot of power, about 400 watts at idle, is a royal pain to bias, you need a long probe to get between the cluster of 4 outputs per channel and the bias is quite high at 65ma. The recap kept all the good parts of the 808es, while just adding another level of clarity and just a touch of sparkle in the highs. For tube amps of any reasonable vintage, this is a no-brainer, IMHO. zxow yykis kfj yuvlpk yzvyywk gosfc tbpoh mlt ozcntd kmck