Sean Connery Solves the Mystery of the Unknown Guitar Amp

[@johnpierson8398]

Hey Brad, I have watched several of your YT videos and I want to pay my respect for your down to Earth, intuitive and deductive approach to electronics and the art of troubleshooting! For me, the way you present a guitar amplifier repair project is fascinating. I am an EE and have been playing guitar constantly since '73 and I have worked on most of my tube amps. I've worked with many engineers who cannot breakdown and analyze troubleshooting jobs. I will be candid and tell you I think your electronics knowledge seems to be informal and self taught. And that is not a bad thing! This is where I come from. But it is your approach to your craft and how you present a story that sets you apart from most. Thanks for the great videos and insights into guitar amplifiers!

[@malcolmhardwick4258]

You should get into the business of making amp kits and teach us how to build them !

[@YeeThirty]

There is major liability there...

[@meirionlloyd-jones7645]

Great stuff Mr Guitologist,very clever mods and transformation ,pretty good playing as well,couldn`t` possibly comment on the "Mike Yarwood " act-lol! very entertaining all the same ,keep on soldering!

[@wamgoc3637]

I think those things are "Couplates" and were a predecessor of printed circuit board construction. There were a number of standard designs which were stock items and usually were made to implement some tube manual circuit. Most off brand US made electronics were cookbooked from tube or transformer manuals, or similar.

[@frufru0071]

Fantastic work, and great playing. Thought I heard a jazzy intro to Stairwell to Purgatory? Thanks very much for sharing this with us.

[@markbratton111]

Thank you brad! I always walk away learning loads after watching your videos. I am not sure if I will ever go on to repairing amps in the future. However, Gaining the understanding of the manufacturing dates and manufacturers codes is extremely beneficial. Sean Connery would be proud. :-)

[@SuperHeliboy]

Interesting video of amplifier archaeology. Your knowledge and competence of these mysterious boxes of sound always entertains.

[@tomaskey6844]

Wow! I'm impressed at your work. Your research was interesting and then the way you reconfigured the wiring shows you have a deeper understanding of amps than it would take just to service one. I'm hoping to build some tube kit amps some day soon when I can quit truck driving. I'd like to build the amp and then make custom wood cabinets for them as a hobby.

[@Beelzybud]

Regarding those "weird a** couplets"; I have a Marvel Amp and opened it up to look and it has the same circuit and front panel graphics as this one. But on those "couplets" the manufacturer is not blacked out. They both say 6302, so 2nd week of 1963, and 710-516 ERIE , and 711-511 ERIE. The "ERIE" is in the location where it's blacked out on this amp. I can send you pics if you like, and if you can find any info about them I'd be very interested.

[@TheGuitologist]

Sorry I missed this comment before. That's interesting. Thanks for the comment!

[@amdelux1]

Thanks Brad , I'm glad I sent this little piece of American history out to you. What an interesting and informative video love the humor too, lol.I'm a big fan of these"crappy" little practice amps they work great for low volume practice and it's fun to throw a mic in front of them too.This one was just too cute to leave sitting around in disrepair and will sit proudly in my collection of other little amps , Silvertone, Harmony, Gibson , vox ect. I found it's much cheaper and interesting to use these little amps instead of buying overpriced boutique amps that basically copy the design of many of these older amps.Its good to see someone who's passionate about what they do. Keep up the good work ✌🏼

[@TheGuitologist]

Glad you like it, man. Thanks for sending it to me.

[@jeffreywood5139]

Just a shot in the dark but I think it may be a 'Sears' amp. The Danelectro quality to it makes me think so and Sears in that time certainly had the distribution to make a multi regional - parts compilation construct plausible...

[@robdefrancesco8928]

I Love watching your videos Brad! Your knowledge of this stuff just fascinates me. Great Channel!! I own 2 Bugera Boutique amps and my older Brorther owns 2 Sears Silvertone amps. One he bought (Head with a 2-12 Cabinet) for $8.00 at a yard sale back in the late 70's and someone he knows sold him a smaller one for $50.00 a couple years ago. Pretty good deals!

[@grahamblackmore2632]

I thought the clone guy was gonna add impressions over your stuff some kind of sick fantasy. I watch in awe I think it s amazing how you keep so calm with open amps I know its years of experience I play I just got the reissue of the thunderbird s200 its fun love that gibson you had like a jr with a flying v head and with the pic ups it sounded like a strat.Great channel.

[@dearmingsacayanan]

This connects in a way to the movie Dr. No where Bond turns on a vinyl record player in a girl's apartment and waits for his supersize assailant as he plays solitaire.

[@henriettademina483]

One possible reason for blacking out the Mfg code/name is that they may have been rejects. They didn't pass quality, possibly for a reason that made little or no difference in sound, but just bad enough that the company couldn't sell them to some of their customers or just didn't want their name on it. They would have sold them cheap because of that.

[@georgethomas9436]

Wow. The playing at the end speaks for itself on how well this amp was brought up to standards.

[@southamericanrocker]

I would have separated the back panel from the amp chassis... Maybe there was the name and make for the amp. That panel seemed replaced...

[@walkerbelle]

Lafayette? My dad use to work on & build the vintage electronics kits and amplifiers and that paint scheme to me looks familiar to so of the vintage Lafayette items he use to build/repair. The company was called Lafayette Radio and all of their stuff was sold as kits that had to be built by the buyers.

[@tiki_trash]

That's what I thought Lafayette or Meteor. Before I clicked on the vid I was thinking it was Selmer.

[@waynegram8907]

Why are they using a 47K resistor to separate/isolate the Chassis buss ground compared the Neutral LINE Ground? as well as the Filter Capacitors ground is tied to the transformers secondary center tap that is NOT at zero but at a positive DC offset voltage. So all 3 grounds aren't tied together which doesn't make sense where is the Star ground.

[@6ixslinger]

GE tubes: 188-4 and 188-5 indicate a tube made just down the river in Owensboro, although the old Ken-Rad plant is gone now, replaced by a city park. 188-20 and 188-21 would be the plant in Schenectady, NY.

[@TheGuitologist]

I used to live over in Evansville and deliver magazines in Owensboro. I probably drove by that old plant 1000 times and didn't know what it was. Lots of history there for tube technology enthusiasts. I probably have hundreds of tubes in my stash made in that plant. The GE Compactron tubes used in Ampegs were developed by engineers inside that facility. I just looked on Google Earth and they don't even have an historical marker on the site. Travesty.

[@ergbudster3333]

Wo! You scared me there, Guit guy. When that drill started up while you were pokin' around in the amp from the previous shot I though you were gettin' zapped. Back in the day when my old man built amplifiers we were always pokin' around in hot equipment. And as you well know some of them tube ckts are energetic as hello there zap zap! Anyhow, another great show. Great series.

[@douro20]

I don't think I've ever seen a 35W4 that clean before, and I've been in a lot of old tube radios. The type markings on GE manufactured tubes are pretty much bulletproof as they are acid etched into the glass.

[@JustChiminin]

He's like a wizard, he can put great tone in anything!

[@davemassie3726]

Happy fools day Brad, great work, good vid, sounds great. another kitchen jam amp! keep up the good work Tonemeister.

[@nevillegoddard4966]

Hi Brad great video. What goes on inside those hybrid 'couplets' in that amp? Are they R-C networks or something? Was there no reference book of some kind for these things, or were they a proprietary part? I love the sweet sound that emanates from the box! I thought it was gonna sound crappy in the beginning, with all the noises & crackles it made. But miraculously, after you'd changed a coupla parts, it was transformed!

[@DeadKoby]

I'm always amazed at how crappy the build was on these series filaments... it was very possible to make a good sounding amp with that technology... Guitar Center mentality was alive and well back then too. Does it turn on and make sound? Will it last past a 90 day warranty? Good, go for it!

[@daw162]

Consumer related stuff was pretty much crap forever, if it wasn't outright scammy. Early woodworking tools for hobbyists were nearly unusable, and expensive at the same time. We probably live in a better age for quality (if you're willing to pay for it) now than there ever was in the past just because youtube/etc. exposes junk quickly.

[@budwhite3570]

Great Sean Connery imitation. I find it amazing how something as old as that can be refurbished to like new or better standards.....And wow, even as old as these are that they sure do go for alot of money only, like the others you showed, I mean, hopefully at $400 like for one similar that its already rebuilt,...but now we are talking nostalgic collectors value folks would like to have "just like in the day".

[@bobsaturday4273]

seems you've been sniffing one too many burnt resistors

[@TheGuitologist]

I picked the wrong week to quit sniffing glue.

[@pXnEmerica]

Snag your soldering iron on some of that bubble wrap, you'll be fine.

[@13opacus]

lead poisoning?

[@bobsaturday4273]

the old carbon composition were bad enough but the enameled film are too stinky

[@themightychabunga2441]

Great Airplane quote and also a great Boris Karloff impersonation.

[@lectrickwall4479]

AirLine relative, maybe? I built an amp from a 3-bottle wine box & used an amp using the same tubes as yours that I pulled from an AirLine portable record player, circa 1959. Also, very "hummy" just like yours. I never did get is worked out but it looks adorable!

[@TheGuitologist]

Airline was Montgomery Ward. They were Chicago-based. Didn't make any of their own products really, just retail and catalog sales.

[@scottgibson118]

Great vid, as always - I have an old Marvel 35 combo [circa early 1950s] with a 5Y3/6V6/6SL7 complement - as with your own observation, seems you can't find a goddamn thing about these Marvel 25/35 amps on the internet - I wound up tracing out the circuit by hand and recently rebuilt it; got rid of the dozen or so wax capacitors, etc., I imagine these things must've been cheap already back when they were built, but they're kind of fun to screw around with at home.

[@TheGuitologist]

Pretty much anything from the golden age of guitar amps - 40s-60s - is a joy to work on.

[@johnthrelfall5]

That amp sounds crisp and sound and full toned after the service. When the guitar signal is not played the hum ramps up but when the guitar plays again the hum disappears , I don't think it is masked by the signal. So it sounds like an agc circuit or compression circuit as mentioned in one of the other comments. Is this a function of the low plate voltage on the 12AX7? Good video!

[@TheGuitologist]

Agc on cam.

[@barrychristiansen4579]

again, very nice touch! simply wonderful . enjoyed

[@johnthrelfall5]

Amazing how these small 4 watt amps were built in several local factories (even here in New Zealand) and the transformer manufacturers , capacitor manufacturers etc , all localized as was much manufacture , maybe not so much big multi-national companies in those days?

[@TheGuitologist]

I'd have to think there were all kinds of opportunities for smart entrepreneurs in 1960s NZ. Shipping is expensive, so if you can make it to satisfy local demand, you'd do well.

[@arbitrarysubpixel]

Would you mind posting the new circuit?

[@chokkan7]

A jet pack sequence would have salvaged the entire effort...

[@TheGuitologist]

I did do all my own stunts in this one, if that helps. :)

[@shadowshop1]

hi i have seen the chips before 710-516 have you tryed RS stock in the uk i 100% have seen them before i work on ace's reel to reel they are all rs parts in them

[@MrBrymstond]

Unfortunately I live in Schenectady County and GE is a couple miles away

[@gillanland]

How did you get rid of the hum eventually?

[@bluesb52]

that tube arangment is the same as the 60's kay amp

[@sandrawinkler8965]

Uh one question.... Those cooplits are they coopled together? Or are those couplets coupled together?

[@ynot6923]

Your Sean Connery very quickly turned into David Attenborough.. great vids buddy 👍

[@gainstageeffects1235]

What are couplets?

[@bartnettle]

Great impressions ! A pleasing voice you have!

[@danvanlandingham3854]

Great impersonation.I enjoy your videos.It brings back memories of when I used an old '40s reel to reel tape recorder as a guitar amp.

[@williamknell864]

That turned out nice, Brad.

[@TheGuitologist]

Thanks William.

[@phydeauxddog]

Amplifier finally hit puberty and those balls did drop.

[@shadowshop1]

hi the blacked part says RS on the old red IC all part that are made by RS are maked THIS amp looks like some one has made it in a home work shop

[@brianyork5510]

I wonder how much the mob had to do with price of shipping, or preference of what got shipped. That jumped in my mind as you were discussing that subject.

[@TheGuitologist]

Brian York haha...didn't think of that. Maybe I should work on my Marlon Brando too.

[@audiotechlabs4650]

The Guitologist Maybe James Cagney or Edward G. Robinson. You dirty rat, we're gonna do it my way, see! Some of my first impressions. Thankz

[@TheGuitologist]

I also do an over-the-top Humphrey Bogart. It starts out with something like, "move that ass out of my way, Sweetheart." And devolves from there.

[@brianyork5510]

Tune in next week to Guitarologist's Improvisational Theater channel where we kick off; Impersonation's of The Golden Era of Film's Actors month with special guest Audio Tech Labs as he reprises Edward Robinson's character Barton Keyes in Double Indemnity. Brad will play Fred McMurry's role as Walter Neff. Barbra Stanwyck role Phyllis Something will be played by Brad's wife who will break character and actually break HIS leg for real with glee while fantasizing vintage amps were never invented.

[@TheGuitologist]

Barbra Stanwyck can be my wife anytime.

[@EC-ol8nz]

Very nice wiring, a lot of work=quality 👍 Sounds like a “record master” tone😁

[@cassvirgillo3395]

Hi Brad, Happy April 1st. Good job on Sean Connery, the Iconic Bond. Nice mod on the amp, sounds really good to me. Nice detective work. Learning a lot from your videos, Thankyou. There is just something about the tone from a small single ended amp. I'm curious if over driving a signal to much degrades it, effecting the tone, sound overall. Take care, C.

[@TheGuitologist]

You can push a tube too far into saturation, yes. If a tube isn't biased properly or is operating outside it's intended specifications, the signal can become squared off or distorted in a variety of ways, producing undesirable kinds of non-musical effects. At one point in the modding of this amp, I had the output tube actually oscillating like a tremolo. The addition of a grid leak resistor fixed the issue.

[@yernickle]

Do you often visit Budapesht ?

[@goodtimefolkrock]

Great sounding little amp.

[@yakacm]

At the start you sound a bit like Zippy who was a puppet from a famous 70's kids show in the UK Rainbow, but after that your British accent is pretty good, it sounds a bit like one of the Cricket commentators, can't think of his name.

[@GasNBullets]

love historical forensic research like this. sounds fantastic

[@theothertonydutch]

Do you post those diagrams anywhere? This seems like an amp I'd be able to build.

[@TheGuitologist]

No, but if you hit Control + Print Scr on your keyboard while the schematic is up in the video, you can paste it into a photo editor and print one. ;)

[@theothertonydutch]

Fair enough! Thanks! :D

[@jameshoskins8902]

That's Douglas Fir plywood, nothing like birch which is a white tight grained hardwood.

[@leewarren]

Those 'couplets' are a new one on me. Multiple resistors in one package?

[@clifffton]

Whole RC network in those.

[@kardRatzinger]

68k in a 12AX7 cathode?

[@PoloniumSmoker]

Will Sean Connery be making another appearance?

[@DonCrowder]

Somewhere I have an old Gibson tube amp chassis that's been rode hard and put up wet. Not sure I'd want to wish it on you. :)

[@koosh6876]

Don Crowder i dont wanna say do it buuuut..... You should do it.

[@clifffton]

Motorola used to use couplets on their B&W vacuum tube TV's. Hard to source when they were still fairly new. Hitachi used a version of that on VCR's in the late 80's for video processing. They sucked too.

[@MarkEvans1962]

"More padding along the edges". Solid advice in many pursuits.

[@tyschmidt5609]

Great detective work and great video

[@TheGuitologist]

Don't thank me, thank 007.

[@richardgallo3155]

Great video! So entertaining... 👍 Love these detective episodes...

[@frankstone919]

It has the sign of Argh in it's design , Maax and the Jun Horde bought some of these to placate the Death Guards. Didn't take much to get them excited ...... Their brains were damaged so , they had a hard time keeping strings on their guitars , with those Freddy Kruger hands. It was a sad tale .... Maax was like a father to me. He was heart broken when things went south , one of Guards quit the band ...... then we got Slip Knot. Wow you fixed it right up , sounds pretty good.

[@DAVIDGREGORYKERR]

Is that a HH.Scott 233 or something

[@waynejohnson6594]

Wow! Sounds good. Great job!

[@aubreyfstewart6626]

where are you situated ?

[@INDYOSKARS]

"Exactly my dear Paxton, exactly" Sean Connery in some movie.

[@ajhnubia]

Hi Brad these red components are known as thick film devices, the idea was to reduce component count. an early idea before ic's

[@TheGuitologist]

Yeah, I've seen them called "couplets", so that's what I go with. Also "thingamabobs" works. Say that and I instantly know what you're talking about.

[@NHguitar57]

What are the specs on the variac you use?

[@TheGuitologist]

This is the exact one I have: amzn.to/2o0rGZf

[@philliprowe1893]

Couplets are good for the maker but you would be screwed if one of the individual caps burned out!

[@georgeallison6228]

love the sound of this amp..crisp and classic

[@fredchatham6680]

I had a similar amp when I was a kid named ELIPCO but never knew much about it. I didn't like it because it "wasn't loud enough" and don't know what ultimately happened to it. Probably same place that Dano/Silvertone is because it didn't look like a Strat. If I knew then . . .

[@alvildeshirven3571]

God damn that thing sounds gorgeous. I need one.

[@palladinwebb6135]

An absolute *gass* [do they still say this?]. Much fun.

[@JoelzombieThomas]

Did I not nail it on the kentucky accent on one of my last comments? I'm proud of myself.

[@JoelzombieThomas]

You're great at other accents too, I thought I remembered trying to guess where you're from and now you said "right up the road" about a Kentucky component maker, so... I'm a good guesser, right? So... have you seen Zardoz yet?

[@AgimLubonja]

Wow what a great sound from that little thing!

[@joesimon2018]

They used that weird fiberous wallpaper stuff on the edges of Dano guitars too. I believe this amp will shock the hell out of you if you touch something wrong. My guess? I think it's Canadian. Personally I would have just gutted it and installed a Champ kit into it. Saving the chassis, speaker and cab.

[@AdamRainStopper]

Huh....one 12ax7, 50c5 SE output, 35w4 rectum-fire, series-filament. I had a little reel-to-reel amp from a flea market, it had a really crazy transformerless power supply though. Wait, I didn't see a power transformer. I need to try and dig out that amp, I bet it's the same chassis, just slightly modified to be used in a tape machine. Either way, it was a great amp for one kind of sound, and that is an incredibly compressed, saturated, almost fuzzy dirt, the kind of sound where you don't even want to play a chord.

[@TheGuitologist]

Most series filament amps of this sort use either 50C5 or 50L6 power tubes. It'll probably be one or the other. The 50C5 7-pinner seems to have more raunchy crunch when overdriven.

[@AdamRainStopper]

Yeah, it could be crunchy at about 10 o'clock on the volume, but it became straight up hard-clipping fuzz when pushed past that point. It was a great sustaining lead-tone. 34 Volts on the 12AX7 huh? That's uhhh....starved plate, like the BK Butler pedals. But what do I know, my hair is blue and I'm a little baked.

[@MikeGervasi]

RIP Sean. We'll miss you.

[@DunsysGuitarWorld]

Send the script and I'll happily do an Edinburgh accent for a future video edit. It may not be understandable, mind you.

[@jasonrobinson5854]

sounds great with that Dirt! Excellent job man!

[@TheGuitologist]

Thanks, Jason! Yeah I think it has a nice recording tone. Would sound great in a nice blues mix.

[@richardneubauer4395]

Looks to me to be a 1962 Dumble Overdrive Junior.

[@tomcurrie7249]

Quite possibly a Gregory or Lafayette branded amp. Not a Danelectro, HIlgen, Sano or any east coast company.

[@TheGuitologist]

Well we do end up solving the mystery of this one at the end and it is indeed an east coast amp, IMO.

[@akachurak]

Thanks for the videos !!

[@TheGuitologist]

Thanks for watching!

[@buckaroobonsi555]

Wow it sounds so much better now. Prob. the best it has ever sounded!

[@bluesb52]

sounds like the kay model 703

[@rogerdavis7770]

Brad do you know what mingin' and pongin' means in Scots dialect??

[@bernhardnizynski4403]

Nice guitar playing!!!!

[@cutsrosescents4950]

Also branded the Yee Haah and sold through Johnson's Feed & Grain.

[@ryanheard]

This is profoundly weird. Shine on you crazy diamond.

[@stevenmiller5366]

Awesome job!

[@daveogarf]

Its CUPlets, NOT COOPlets. They were proprietary bits of sub-circuitry, mostly resistors and capacitors, designed to hide circuitry from prying eyes.

[@williamhill6705]

i say old chap, thats a frightfully convincing english gentleman living in there with you .the blighter has a damn sight better accent than your average amp tech, pass me the magnifying glass my dear watson, this box of tricks has it wires crossed !

[@yrulooknatme]

In the pocket Brad, sounds really good .

[@ribbonsofeuphoria5744]

Just clicked... will it be a Shupro?

[@jonnybeck6723]

That handle and the almost shoddy workmanship... Its the 12AX7 that throws me. Have Miss Moneypenny send for Q before someone gets injured... Reminds me of a kids phonograph with the flock on the turntable... Emerson? (just a wild guess)

[@iridium7736]

www.tdpri.com/threads/new-auction-find-marvel.272591/ - certainly looks like the same circuit.

[@BrianOfAteionas]

Looks basically identical. Same face plate graphic, and plywood as well (as far as I can tell). Is the amp in the video perhaps an unbranded Multivox made amp? Or do you think it's possible someone removed the Marvel badge? I love these old mysteries

[@VersesRecords]

Bet that would make a great harp amp.