Beyond Recapping: getting the last noise and buzz out of vintage Fender amplifiers

[@stratfanstl]

Another reminder of the many layers of science, skill and art that go into amp design. You can have a perfect theoretical design but still cripple it with bad layout ( turret or PCB). You can have a perfect theoretical design and layout but cripple the implementation with cheap parts or inappropriate ratings / guages or sloppy work. Or everything can be initially perfect then subjected to time and physics and suffer inexplicable issues... unless you REALLY know your stuff. Masterful content here. Thanks.

[@scottwilcox6313]

Lyle, the new camera and audio is fantastic. Really enjoy learning from your years of experience. Really next level on the content.

[@PsionicAudio]

Thank you very much!

[@Satchmoeddie]

@@PsionicAudio I just got THE replacement box for my old $2000 Koss ESP10 electrostatic headphones, so everything sounds pretty darned nice, but yes even with the Sony headphones straight off the laptop, it does sound very much improved and quite nice. I paid $15 for those Koss ESP10s at Glendale 7's old Swap Meet, and those Koss boxes are not compatible with some amps, like Marantz. The ESP10s are divine with other amps and receivers. Koss sells an ESP 950 for $1000 now. Imported versus USA made, and you only get one headset instead of two and there are no mini McDonald's drive-thru style headset boom mic mounts on the 90-900 series.

[@Theweeze100]

Can’t say enough about how invaluable your instruction is to those of us who dabble. Thank you! I also would like to echo that your audio and video quality are off the chart. Thank you for being so detail oriented.

[@voxpathfinder15r]

I remember from fixing cars, there was a level of trouble shooting that involved using the factory manual that involved an implicit assumption that basically everything else involved was perfect. Then there were the cats that understood issues on a deeper level like in this video- where only intelligence and experience will probe further into diagnostic and resolution. People who change components are basically working on the implicit assumptions that it’s components failure and never question the integrity of the foundation the components are embedded into. All being said - issues like this give me a better appreciation for higher quality thick pcb construction. Although that crap can go conductive as well - hopefully only because manufacturers chose cheap thin pcb boards.

[@NILOCOgov]

Back with a bang. This type of work is so satisfying to watch.

[@YeatzeeGuitar]

Haha I'll take the shoutout 😆😆 Tubes ended up seemingly fine but they were burner tubes either way. She's all good now! But yes, learn from me folks be EXTRA sure where everything goes.

[@rinkydinky-ob9pe]

there's nothing like watching and listening to a great lesson , lyle really is an artist and a national treasure

[@MrCarlsonsLab]

Nicely done! Thanks for sharing your video.

[@PsionicAudio]

Thank you sir!

[@poormanselectronicsbench2021]

Good tip for getting some of the last noise out of a tube amp! If you have a DMM with a "conductance" function, like some old Flukes, or the 8X - 18X series meters, or a Brymen 786 or 869S, they can measure extremely high resistance leakages while using single digit voltages. For example, a conductance reading of 0.01nS , or , nanosiemens, is a resistive fault of 100 gigaohms, and can help you identify low level leakage from point to point on a board. Of course, component removal like you did is still necessary, but it can help you verify if you have made a improvement before resoldering everything.

[@desert-paradise]

Superb! I could (and often do) watch and listen to you work on this stuff for hours - always fascinating.

[@Schlumpf.Meister]

I own a 69 SR that had been overhauled by a famous German boutique builder in the process of which he removed ALL capacitors and most of the resistors. when I bought the amp from the past owner, I received along with it a huge bag of components and the original 700€ invoice. The amp was dead quiet and sounded heavenly. However, some component values had been changed (tonestack, one coupling cap). I changed it back to original using some of the original components which I measured prior for defects. The amp is still dead quiet and sounds even more heavenly. So I wonder if this huge overhaul was really necessary.

[@jjiacobucci]

Leakage in the board ! Who would of Thought ! Thanks for the explaination !

[@alasdairmunro1953]

Really interesting to see you doing this. I’d never have considered the wax as a problem. Every day is a school day. Thanks Lyle!

[@nichesound]

Leakage can be so frustrating. I usually reheat/add new solder first and then clean up similar to your video if that doesn't seem to do the trick. Recently bought a clean 1973 Twin Reverb/master volume that needed new cap job. These older Fenders are tanks! Nice job.

[@omen3766]

...."because it sucks.' yep you done won son. Thank you for the education and the wit.

[@krauz111]

glad to see you back! I was missing these videos

[@PsionicAudio]

More to come!

[@jasonktong1]

Fantastic Lyle...I almost feel ready to look at an old Fender now. I have a '70 Super Reverb here that is staring at me...

[@Cpt_Adama]

You have a great "Radio" voice.

[@theguitaramptech]

That’s got to be one of your best videos, Lyle! Great work, oh captain my captain!

[@YeatzeeGuitar]

Hey you're back! Missing my fix, love the vintage stuff I learn so much from that. Just wrapped my Vibrolux project and uploaded the final video of the series today. Thanks for dropping by earlier, appreciate the encouragement!

[@PsionicAudio]

I just watched your last video. Sounding fantastic, especially with your ES-330. I was going to contact you, but maybe this will be faster. You have the 25uf on V5b like the schematic, but Fender actually used 5ufs in most production amps. It gives a better response time for the Speed pot. PS I’m going to be doing a “small channels you should be subscribed to” section on my next live stream. You’ve made the list. I enjoy your stuff.

[@YeatzeeGuitar]

@@PsionicAudio Thank you! Good to know on the 5uF, I had to end the series (12 parts, goodness what was I thinking lol) but the amp isn't 100% dialed yet as there's also the famous tremolo tick that needs to be solved but that'll happen off camera. I'll take a look and give that a try. And wow, thank you!!! Really appreciate that 🙏

[@PsionicAudio]

Ticking is usually solved by adding a 10nF or 22nF cap across the roach from the 10M eyelet to the ground eyelet. Try that first.

[@PsionicAudio]

PPS 5uF caps are hard to find. 4.7uF is the modern standard and is equivalent.

[@matthewf1979]

@@YeatzeeGuitarI have the Sprague 5uf bypass cap and 10/22nf ceramic or film if you need them. I have plenty of stamps left that I never use!

[@curtisprice9806]

CRITICAL KNOWLEDGE I NEEDED TO GET RID OF NOISE IN THE GREATEST TUBE AMPS ....!!! THANKS!!😁👍

[@tomk1tl39]

Tks Lyle for this tip that I did not know about the wax causing these issues . . .you are a very 'rare breed of guitar amp tech' .. .stay safe ;-)

[@TheArtofBlues]

This is my fav type of video now. Thank you so much!

[@davidtreaster4397]

Thanks!

[@fredcoston6580]

The hissing and noise. I wished I knew about wax leakage but the amp is great now for 30 years . I put in Torres bassman magic kit . This amp is loud and proud. Thank you for sharing your knowledge.

[@LarsonGuitarPlayer]

Many thanks for sharing this supreme level of knowledge. This is maybe the one video I will value the most of all that you've made.

[@rockitlikeawolf]

you truly are very kind to make such information-rich videos. thank you.

[@camielkotte]

Such valuable information. At some point I will recap and clean my 78 super twin reverb. It hasn't got much historical value but to me. Love the cleans. If I break it I will buy de drri

[@DetroitWrecker666]

Fantastic information!

[@rickcurtis2983]

Excellent learning video, thank you!

[@oldguy5381]

Always grate information thanks Lyle.

[@chippsterstephens6800]

Such outstanding work, I have been absolutely ragged on for this very issue, while pointing out to people, a bad cap, will show leakage on a high voltage capacitor tester if it actually leaks, and that the blue esr meter will show esr values on a small signal cap once you read enough esr values you can tell what’s good or bad, esr on small value caps is very tricky, anyway , in doing vintage work, 100s of blue molded caps tested, I have yet to find one that is actually a bad cap, yet people insist they do, but never have said blue molded cap that was “leaking”? To show me , or let me test, I have said, Its the fiberboards. A little heat goes a long way. Just like you show here. I think the larger problem is few have a real capacitor tester that can test at rated voltage, and esr meters mostly do not work on small signal caps. So they shotgun parts In vintage amps religiously . While seriously devaluing a vintage amp. I will admit many other caps do not fair as well as the blue molded film caps do. However if they are not bad, they also would not need to be replaced, and to know the difference is fairly important on a vintage amp that has a rising value. I still have an open invitation to anybody who thinks they have a leaky blue molded cap , I have a stancore capacitor analyzer , if I find a bad one it will be a first. If someone with proper test gear showed me one, that would also be a first.

[@swaffy101]

Very valuable info and your subtle humor is amazing!

[@ToddRichmond]

"mmm, tone goodness" and "he's taken all the vintage out!" - will be borrowing those quotes for future random conversations...

[@ClarenceHW]

Amazing attention to detail, enjoy watching you work, thanks a million.

[@SteverRob]

I hope you don’t mind, but I binge listen to your low, calming voice to lull me off to sleep at night. Don’t get me wrong, you’re my favorite amp channel. Maybe I can absorb some of your vast knowledge in my sleep lol

[@giulioluzzardi7632]

Great video, I can see everything. I was fixing an old battery powered Disnei toy and of-course I thought the memory chips had gone caput(hot , sunny, sea-side envirinment) heated up soldering iron and had new wires ready, as soon as I touched the battery terminal the thiing came back to life! Animal sounds, laughter, sound FX etc. The salty sea air had made the battery terminals turn to powder!? Anyway all was well after new wires. As you say it is the fact that you are heating those "cold/dry" connections that causes the circuit to re-connect. Thanks.

[@fredcoston6580]

Lyle , I picked up a 1965 bassman in the 80s . I tried all types of repairs . Finally I replaced the fiber board with epoxy board from Hoffman . We'll it stopped

[@boogierandy7547]

Youre the best Lyle.

[@edwardhannigan6324]

Cool video and very informative..Thanks for sharing..Ed..uk..😀

[@romannumeral5547]

Just a great video. Never would have thought that wax would cause that kind of issue. I've dipped my toes in the water by gutting the PCB from my Blues Jr III and replacing it with a turret board and point to point wiring. Now I just have to figure out some tweaks to get the sound where I want it. Into the rabbit hole we go. 😁

[@Slugg-O]

Proof there is no substitute for experience! Very nice tip. Thanks!

[@watkinscopicat]

so great to see the late 70’s SR get some love, they’re wonderful amps if you take good care of em.

[@tedmich]

Finally a mic and sound recording deserving of your rich baritone! So nice to hear (and see!)

[@jerryking2418]

Great advice and interesting video. Thanks for sharing.

[@JohnBowen-xs1vf]

Hi, I’m the guy who asked about the Princeton Reverb II. Somehow, I missed replying to your comment. I’m sorry about that. I appreciate your comment- saved me from making a mistake. At my age I don’t have time to make those mistakes. Again, Thank you! John

[@BradsGuitarGarage]

I know how fun the wax cleanup is, believe me!

[@danielmargolis3210]

Really beautiful work.

[@PsionicAudio]

Thank you very much!

[@HDYaqui]

Great Video and VERY INFORMATIVE! 👍🏽😉

[@PsionicAudio]

Thank you! 👍

[@rightlurker4674]

Excellent. Thank you, Lyle.

[@duroxkilo]

fascinating, i didn't know about wax becoming conductive enough... i did encounter insulating materials (such as foam spacers) that measured a few tens of ohms in older amplifiers.

[@chokkan7]

Lyle, you stop that right this minute! You just put all that vintage mojo right back where you found it, young man...the very idea...

[@halhawkins7641]

this is awesome common sense stuff.......that comes with your experience!

[@ThelBosch]

“He’s takin’ all the vintage out” had me chuckling. Sounded just like the guys around here (Northeast Arkansas) 😆

[@PsionicAudio]

My family is from Jonesboro.

[@ThelBosch]

@@PsionicAudio No kidding, that’s whete I am 👍 Small world! I was born in Memphis but moved here in 84

[@jamespell8091]

I have never really worked on amps (or really as much) a long time ago my grandfather did a cap job on an amp I had. The board was nothing like these here. Just the cap job alone and how silent the amplifier was after floored me. This is a very good tidbit. I have a fender 75 I would like to approach. It looks like a monster of a circuit.perhaps a difficult one to diagnose. A little problem like this would drive me nuts. For I am spoiled of how the silence sounds.

[@Murry_in_Arizona]

Great Wednesday night, Lyle dropped a video and the wife brought me home a pork tenderloin from Culvers for supper.

[@MatthewFarrell-s2w]

Interesting and informative as always, I just hope the tech currently servicing my own late seventies Pro Reverb has the same skill!

[@unclemeat8422]

Camera and lighting upgrades looking good!

[@daveogarf]

"He's taking all the vintage out!" 😱

[@conradborba4324]

The new camera shots look great!

[@PsionicAudio]

Thanks!

[@49VinCom]

Great video.

[@roberthastings708]

Oh my. I never thought about the wax issue. Thank you. And I got the vacuum sucks. Low hanging comedy fruit well played.

[@brucetaylor1753]

I just looked and saw that you have over 38k subscribers now. Wow! When I subscribe you had 500 and something. Congratulations and I guess I should look more often at how many subs you have.

[@PsionicAudio]

Thank you so much!!

[@Billywagner22]

I dig the subtle humor, yes vacuum cleaners do suck.

[@RedArrow73]

Learnt something important here.

[@grinchouj-pascal6618]

Outstanding video. Any advice on soldering iron, temperature and solder brand?thanks

[@nigelbishop8108]

Brilliant video

[@matthewf1979]

Hey, I know that “guy” you’re talking about! I was live tech support for a couple hours helping him get it straightened out. I have the luxury of not doing this stuff full time though.

[@YeatzeeGuitar]

You're the man, thanks again! 🙏

[@pwman]

Lyle this was a great video! You know you could save that wax and sell it … a great surfer vibe! “Fender Sex Wax” - Give your board that smooth vintage tone! 😅😅😂😂😂😂

[@artysanmobile]

On my own amps, I have used glyptol, a red insulative ‘paint’ of sorts at a few critical locations. Once the board is squeaky clean and tested, it can be applied between lands which are likely to be a problem. It’s just my theory, but I believe this can be a permanent solution to make up for sloppy PCB design placing high impedance signal points too near to high potential signal which… happens. From my 1970s work on A/D converters before they were chips.

[@peacefulwarrior1959]

ditto most of the comments another master class much thx sensei

[@sseltrek1a2b]

great vid...

[@Satchmoeddie]

And easily converted to "quasi" blackface specs. Those old blue epoxy dipped Pakton caps almost NEVER ever go bad. I found the manual for my GR resistance meg-ohm bridge. I can make a high voltage probe, kind of like a snuffer stick only with a 1meg ohm to 10 meg ohm resistor inside of it, and test resistors AT 1,2,5,10,20,50,100, 200, 500 or 1000 volts, and find out if that resistor is good at the high working voltage it sees inside of a tube amp. I can even feed that exact voltage from the amp through the bridge, as it's just a null bridge. You get the needle to center, and read off the resistance. It also does the insulation resistance test too, so you can check those boards for leakage up into actual tera ohms. The voltages to test to tera-ohms are kind of, We'll make it leak, ***damnit!, high voltages.

[@jeffmaloney3843]

Nice work, Lyle. There’s so much misinformation out there. If only all could see this.

[@david25876]

Very good. Thx!

[@soapboxearth2]

Omg not the tone wax!? All that dc mojo , gone ? Lol Very cool video

[@TheAmphibic]

great stuff!

[@danweston6109]

A lot of people talk about your dedication to good practices and craftsmanship, attention to detail. Not enough people talk about your voice and cadence please read me a bed time story, maybe GPS directions at the very least a few books on audible.

[@ninocarlitos5229]

I own Fender amp from that era, it's 1979 SF Bandmaster with MV. Simillar cables, resistors, & caps. Perhaps simillar noise & buzz issues tho. However, the boards get bend and warbly, so the first thing i did is changing all coupling caps then addressing some cable layouts, the noise lowered but it's still there. Then I change some tubes, nothing change drastically. My questions are, Do you think pulling out the board then wash it completely will fix the issue? Or just replace it with new & fresh boards? Last question is, do you think those cables would survive for next 10-20 years? I live in Tropical country anyway, so humidity level can go wild for several months in a year.

[@DeadKoby]

It'd be cool to see the blue cap leak tested whilst it was out.

[@PsionicAudio]

It was leak tested when it went back in. Zero volts DC.

[@christophersambuco9414]

I'm almost positive that Yeatzee did his work on his Vibrolux inspired by the workmanship that you demonstrate in your videos. So basically, I need to go back into every amp that I've worked on, and do it the right way 🙃

[@nolarocks]

Good stuff

[@benlogan430]

Ohhhh 😮removal of the sacred mojo wax!

[@charlesjaphe]

Good info

[@jackmundo4043]

Wow. Thanks.

[@2tallB]

Good stuff! Do you typical clean the problematic areas where HV wires are in close proximity, or do you test for leakage at those points first and then clean? (Assuming the amp has noise but no other issues)

[@simonkormendy849]

If I were restoring an amp similar to this one, and I was the owner of the amp, I'd keep all the original good parts and replace the fiber eyelet board with a new FR-4 Fiberglass turret board at least 1/8th inch thick, and that would fix the DC leakage issues for good.

[@PsionicAudio]

Yeah, maybe. I don’t think that meets the definition of “restoration” but… A big part of being a tech is working within the client’s budget. The DC won’t return at these nodes for decades given normal amp use environments.

[@scottbarattini9180]

Tone goodness he’s taken all the vintage out. Lol

[@silviopimentel7247]

I have 70's one that need a output trasformer wondering witch company would be the best ?

[@MikeM-Colorado]

Only one click of the ‘like’ button allowed. Not fair. I love saving the old parts! On a 60s board without wax, would you just remove the components and heat the area?

[@PsionicAudio]

Thanks Mike. On non-waxed boards I remove the components and solder as shown, then soak the board in isopropyl alcohol, wipe off all surface gunk, then drive the alcohol out from the areas surrounding the eyelets with the soldering iron (you can see rings of dry goodness expand out from the eyelets - the alcohol displaces the water from the board in the process), then heat the rest of the board with the hot air gun. Then I put everything back, and if the soaking was intense, I wait a few hours before powering back on. Let the alcohol fully evaporate.

[@MikeM-Colorado]

Nice! This is going in my repair notebook. Thanks much!

[@nicholasberndt6224]

I’m still relatively new to this… So that’s what all that wax was for!

[@sonnysilversmith2156]

I was curious to look inside my 79 Super Reverb and I noticed a couple of white plastic wire had good burn mark on each, how do you address the burn marks, I don’t see the bare wire but it is deep burns. Also I noticed at the first power tube socket, where a tube pin socket was loosely protruding out of its hole, like it became loose, is that a problem or is that normal.

[@PsionicAudio]

If you don’t see wire you’re ok, even with burned insulation. It’s just not optimal - I’ve seen it in lots of factory work ‘70s fenders. If a tube socket is loose, tighten it. That’s a must for safety and tone.

[@trapperjohn8481]

Is there something that would make a good replacement for the wax if for some reason it would all have to be removed? I've seen many videos of techs basically giving up or claiming the amp is too far gone to be worth repairing when encountering this and other issues related to a board becoming conductive.

[@mkii1964]

I have a 1967 18watt 2X12 combo that has a hum, it might have this same issue?

[@PsionicAudio]

In an old Marshall, hum is usually electrolytic caps, dirty chassis grounds, a not-optimal ground scheme, and if yours is cathode biased, mismatched output tubes.

[@mkii1964]

⁠ Thanks for the reply! I’ve tried different tubes but no different. Could you check it out for me? I’m a little worried about using it with the loud hum…

[@silanman]

there's knowing how to do something....but knowing when to shut up and listen to the guy who understands why you do something....that's the lesson....

[@danielsaturnino5715]

Hmmm is that a piece of lead on the board right at the end of the video?

[@PsionicAudio]

If you’re thinking about what I saw, it was just a little thin fleck of wax that came off a component lead.

[@stephenmonike1906]

I'm having the same problem thinking it's the caps,once it heats up the 60 hum comes back

[@roberthurless4615]

I won't show you the vacuum because it sucks. ha-ha-ha, nice pun. Could you possibly do a video on how to remove the MV from these 70's amps? I did one several years ago, but I could use a refresher from someone who really knows what they are doing. I missed your videos btw.

[@PsionicAudio]

Look at this video again, see the wire going to the MV and the wire coming back from it? Disconnect those wires on the board and put a jumper from the joining of the mix resistors to the input cap of the PI. Done. But the MV is fine to leave in place (just remove the nasty sounding bright cap across it).

[@roberthurless4615]

@@PsionicAudio Thank you

[@waynegram8907]

What type of WAX did they use on those boards?

[@raffaele7185]

Interesting. I guess this only applies to waxed boards.