Silvertone Hi-Fi to SICK GUITAR AMP...A Conversion Love Story

[@amdelux1]

This is one of my favorite amps that I own, Brad did a great job on it and everyone loves this thing.Ive tried some other newer speakers but went back with the original Oaktron because it has that warm alnico sound and a lot of volume for such a little thing.

[@kendavis8046]

You brought back a very strong memory with that FOMOCO tube. Of course it was Ford Motor Company (I know you already knew that.) But that is not the memory. From late 1969 (when I was a young lad of 10) until he retired from the Air Force in the Spring of 1972, my late father worked at the NORAD facility in Cheyenne Mountain, Colorado Springs, as a computer tech. And the systems then in use at the Mountain (I only heard this years later, as he was under pretty significant security restraints), the systems that could essentially track everything in the sky, were Philco computers, using core memory, and though I may well be wrong about this, as I am getting older myself and this was years ago, each computer had 32 kilobytes of memory. Anyway, Philco at that point was also a Ford division. Thanks for the interesting content, but especially thanks for sparking a really surprising (to me) memory!

[@TheGuitologist]

Yep. Ford even had their name on stuff like TVs for a while because of Philco affiliation.

[@podrum7421]

The Guitologist please if you could tell me where do you buy all the capacitors and parts... deal is that i live in europe so they dont come so easy. Hard to find them... and tubes also, and if you have a link please post it, I would be very grateful.

[@AOTSismyhero]

www.amplifiedparts.com/ Is based in the US but I hear their international shipping is fairly reasonable for larger orders

[@timlyons5191]

A

[@johnthrelfall5]

Wow! Now it can be told! Ferrite core memories! They would have taken up a lot of space. I remember studying them back in the 60's.

[@umac76]

I laughed out loud when you suggested Sears should be selling tubes again, what a surreal notion. It's so fascinating that with the passing of tube giants of the western world, Mullard, RCA, Amprerex, etc, that you're still so firmly entrenched in servicing the great products that they drove. Keep up the good work.

[@informationsuperhighway100]

This is gradually becoming the best show not on TV!

[@brodieatlas7295]

you all prolly dont care at all but does any of you know of a trick to log back into an instagram account?? I was stupid forgot the password. I would appreciate any assistance you can offer me.

[@adrielspencer9111]

@Brodie Atlas instablaster :)

[@brodieatlas7295]

@Adriel Spencer I really appreciate your reply. I got to the site thru google and Im waiting for the hacking stuff atm. Takes quite some time so I will get back to you later with my results.

[@roncarter2188]

You know watching your videos is one of my favorite things that I love to watch on KZbin. I'm still a complete newbie when it comes to troubleshooting and modifications, but you have definitely given me some good insight in knowing what to do and doing it right. I appreciate all you do keep up the good work, great job on this little amp, it's now a beast of an amp.

[@fongy200]

Since I've been watching your content Brad it motivated me to start college night courses for a UK nation accredited qualification, 2020 that was because of the Covid it's been postponed until June so looking forward to that. Been studying Capacitor and Resistor values etc.. I'm pretty good at reading the schematics too, always been good at working from drawings .Thanks Brad, just building up my gear, I'm out for a variac at the moment just ordered a Vevor 1000VA. It was considerably less expensive than I thought too.

[@JammyCrackcorn]

Those metal based plugs for them are called Tri-Zerts…They had a special pattern tool that snap them into the holes… I’m an ole man and remember them when working on old radios…

[@ALFREDUNIT21-t9z]

WOW , what a sound , love it , one of the best little boxes I have seen here , I will be looking for one of those lol , hats off to you , Alfred NYC / PR

[@Medicated1]

Brad if you ever want to adopt a 51 year old man, It would be a dream to play with all that gear you own! Love your channel and your vids... yourself, uncle doug and Davey from Daves world of Fun Stuff are my favourite channels, I have learned a ton of things that I never would have if it weren't for people like you that share your wealth of knowledge from years of experience! Thanks for doing what you do and sharing it with us!

[@kurtweiand7086]

Thanks for showing this! Wow what a blessing to see the way it all started! Rock on!

[@yqwgjsg]

Damn son. That wasn’t a repair it was a redesign. I could just imagine you standing over the shoulder of the original designer saying “nope”

[@jaecenwhite2590]

It’s funny, though- those negative feedback circuits make total sense for a Hi-Fi where you’ll trade gain for lower total distortion. That 6V filament on the input is weird though.

[@davehebert3403]

@@jaecenwhite2590 I was thinking the exact same thing. OTOH, the removal of the negative feedback makes that thing sing, as far as distortion is concerned. Brian May does the same thing on his VOX AC30, and that allows him to just crank his amp when he needs distortion. He says he gets to use fewer pedals that way and still get the tone he desires.That's a bit harder on the tubes, but hey -- this is rock and roll.

[@graxjpg]

@@davehebert3403 in AC/DC recently, they bias their amps so hot that they blow literally on a weekly basis.

[@brentmoore3778]

I like these videos,where people take something old,and make it better than when it was brand new.

[@fredchatham6680]

Thanks for the peek into your gear hoarding. I feel your pain. Every time I find something I'll "repair then flip", I become so emotionally attached I can't let it go.

[@tomsch5801]

FoMoCo - Ford Motor Company

[@georgelackey622]

Yup! Knew that immediately, just too late!

[@SickLens]

Beat me to it.

[@Brandon-sr8qd]

I noticed that "F" looked too familiar...

[@hairycat6095]

me too

[@peterdavies5358]

I just said the same thing.

[@hardball107]

I am becoming addicted to these video's. In my younger years I collected old radio's and all sorts of amp's and speakers, brings back a lot of memory's and makes me cry thinking about the equipment I let go for peanuts, some just got thrown out like an old Hafler 101 preamp and a 15" Tannoy monitor traded for a 22 rifle. I keep looking for old equipment and trying to play guitar to pass time now that I'm retired. I would love to have you hot rod a vintage piece of equipment to power a 2x12 cabinet, I'll keep watching.

[@JJ-JOHNSON]

Another awesome video Brad, I done seen all your videos a time or two, I have to wait on the new one, so keep them coming. Lol.

[@TheGuitologist]

Got another one in the can almost. And a couple more ideas. After that, you've seen the room full of stuff...

[@dougthetechguy5005]

You sure turned that into an awesome sounding little amp great job!

[@TheGuitologist]

Thanks, Doug.

[@brandonkruse6412]

I learn so much from just watching you work on these old amps. I am a bit of a vintage tube nerd myself, so I got a little excited when I saw your collection! PS: I live in Owensboro, KY and have some old GE 6V6s from the old factory.

[@JohnViguerie]

mad respect. bringing together a mountain of skills and knowledge to outstanding conclusion.

[@Wildman9]

Yep,I agree.Those Ford Motor Company tubes were for the AM radios in the cars of that time. Great stuff,and info .What a trip remembering those tubes in cars ,we used to strip those out of used cars.Thanks man.Going back in time and watching your old videos.😁🎸

[@ziggylayneable]

I'm screwing around digging through old videos and this thing sounds freaking great

[@efallgren1]

Brad. Your video was right on time. I just picked up a Silvertone Model 7074 Reel to Reel with the exact (almost) Hi Fi Amp in it off of craigslist. It has the exact same chassis with the 6X5GT rectifier. Same dual pre-amp section, and yet this one is more complicated with a switchable board... The polygon hole in the top of your chassis in front of the 12AX7 location is for the mechanical switch opening. You set up a good popcorn trail for me to reference turning this into a guitar amp. I literally had the chassis in my lap taking notes watching. I should be able to strip this down a bit to make it ROCK! The Silvertone 12AX7 and 6V6 are currently being used in my Tweed Princeton clone head for the interim and work perfectly. Thank you for all you do!

[@charlesshaw9090]

The .01μF across the output transformer creates a conjunctive filter which will kick in around 4-5kHz to stabilise the OT primary impedance at higher frequencies. That high frequency unpleasant ‘tizz’ on your notes, that appeared when you removed it is why it’s there. It was very common in the ‘60s, often with a series resistor, look at the Watkins Dominator. There is still no ac at the screen so it does not make it triode mode. Also on SE amps it is usual for the first power node to be taken after the Pi rectifier filter resistor. Unlike push pull, any hum on the HT will be heard, because there is no common mode rejection, so the first HT Pi filter stage drops the HT 100/120Hz hum down significantly. Another fascinating video and great noodling.

[@cantfindamerica877]

That screw thing you didn’t know the name of is called a camber, there used on cheap furniture a lot to hold everything together. That’s a great sounding little tube amp, awesome!!!

[@tonycross4519]

Holy slap my Grandma!!! What an awesome tone out of a little suit case amp. Geeezzzoow!!

[@jeffames5385]

Man, you are livin my dream! If I were 10 years younger I'd be doin this kinda stuff!

[@jimbojones5153]

Man you worked wonders with that amp! Sounds absolutely incredible! Well done dude, congrats from the UK

[@0tt0z]

You are the amp whisperer! Haha . I work on and collect old radios so this stuff isn't lost on me but I gotta say you know your stuff and you inspire me to start working on stuff again.

[@izrael2321]

I absolutely love your video's ,very very entertaining and informative

[@TheGuitologist]

thanks, Izzy.

[@micha-elcleveland1265]

Well done, for a little while there we were wondering if you would get 'er done, but you did.

[@TheGuitologist]

We got 'er in the end. Always do. ;) *intentional double entendre alert*

[@barrychristiansen4579]

Hay Brad , just want to remind you as most others are doing , Your vids . Are always well worth watching evertime . I confess . i still forget to like alot of em. but., getting better. Cheers!

[@ExitThirteen]

That's crazy... that thing has near "distortion pedal" type sound at higher volumes! Sounds amazing, even though the sound was "flubby". Love it!

[@sam127001]

Wow - I was not prepared for the sounds at the end! very interesting video !

[@amdelux1]

Wow , Thanks, this thing is incredible.I was surprised at how loud it is in fact the my ears are still ringing , no kidding.Im going to experiment with some12ay7 ,12au7s along with some speakers I'm also going to use an AB box like some mentioned, great idea guys.I can't wait to bring it to a jam .The high channel is cleans up well and has a great classic rock sound and the low channel sounds like a high gain boutique amp , think Mesa Boogie.Thanks again Brad keep up the great work.

[@TheGuitologist]

Thanks for letting me work on it. It was my pleasure.

[@amdelux1]

J& K Real good

[@BeebopConnard]

well that's it . i had to subscribe . Very good content with a smidge of humor and a lot of historical and technical knowledge . Great work !

[@stephenbunton2159]

I am in the process of building a champ style amp with the same chassis as this one but mine was from a reel to reel and had one more 12au7, so 2 12au7's, 12ax7, 6v6 and a 6x5, I am waiting for a capacitor to start it. I have had it for over a year but just recently have gotten to it. Great job on this one.

[@douro20]

I have an old Emerson 560 radio which has those types of quick connectors on the antenna. Personally I haven't really had problems with those types of connectors. I had to repair one once on which the solder connection failed. I'm surprised that physically leaking capacitor didn't take out the output tube.

[@dominickedwardscantore9001]

I like the way you took that stubnorn knob off !!! With a piece of string ! 🤔 that's cool , thank you for showing me the tricks to the trade !!!

[@zeromatt1]

love this channel, great info, Brad is amazing talent in music and in electronics. I would love to know more about Brad's story in reference to guitar and electronics.

[@SyntagmaStation]

Sounds just like he looks. I like that. Great insight about Sears . . .

[@mushkamusic]

That cap substitution to tighten things up was super interesting. Another great vid!

[@marccarter1350]

Great little amp! I am not sure i watch much else these days. Love the videos, Greetings from a UK based Vox AC30 player

[@McSynth]

Wow. You really made that amp sing so sweetly !

[@Droidmaster1]

Hello my fellow solder jockey....OOPS I MEAN GUITAROLOGIST. I’ve been a player for 48 yrs, and a amplifier tech for almost 37. Im retired now, But like to watch your videos. Very easy to follow. I worked on large venue type mainly for Peavy. Your skills are excellent and keep up the heartbeats of all the amps that will eventually (a lot of them anyway) Will become extinct. KUDOS MY FRIEND. STEVE .

[@stevenharrison488]

Why can`t you in the UK I would sit at your feet.

[@johanolsson7953]

Man, that basement! Also, great video! I´ve studied electronics for 3 years in college but lost interest after graduation. Your videos has inspired me again to pick it up!

[@curtzblues]

Such an absorbing and instructional demo of tube amps and schematics. Hats off in appreciation of the work it took to put this all together for us. Makes me want to open my '65 Champ; it needs the same TLC. Nay, it needs the Guitologist!

[@TheGuitologist]

I've seen tubes labeled Ford before, but not Fomoco, to my recollection. Thanks for the comments!

[@joemess98036yahoo]

Ford labels factory OEM FoMoCo and retail Ford. In a shop it is how you can tell factory part from an already replaced part.

[@briantomczak21]

dude, go to harbor freight and purchase trim removal tool kit for a few bucks, it will make taking those knobs off a lot easier.

[@robertpowell2012]

Heat and plastic car door panel removal tools work and won't scratch the finish. They are slim and will slip behind the knobs easily so you can apply pressure from behind.

[@mischef18]

What you do is always way way over my head but enjoy watching you sort out problems anyway. ATB

[@Starcrunch72]

Leslie West tone going on there at the end--wow! And congrats on the ballooning of subs--so fun watching them grow up!

[@TheGuitologist]

Yeah, it's been a whirlwind couple of months. Seems like every other video was just blowing up.

[@kevykev38]

Wow! Awesome playing

[@Ibaneddie76]

Man your shop is amazing, I would love to have an old amp you worked on.

[@chatboxguy3363]

Smart thinking on the knob, last week my friends spare TV had a quarter inch thick long circular shaped peace of electrically grounded tipped metal inserted all the way in a front video AV port all the way to the quick so it was capped off completely. His regular TV had died so we were getting out a spare, and I used a tipped knife from his kitchen to pull it out and then used spaghetti Tongs to clamp it to finish the job. It was very in effective to have the video port capped...LOL

[@fortj3]

That amp and that P90 are a match made in music heaven.

[@MICKEYISLOWD]

Sounds really sweet and organic. Cool job.

[@backspin6698]

Lovely little amp. Sounds good. You’re a wizard.

[@williswet]

Great video Brad! I love to see these type of conversion videos. I learn a lot. As far as not having a 3 wire power cord what I do is simply clip a jumper from the amp chassis to my Variac and it acts like a grounded cord and kills the 60hz hum.

[@audiotechlabs4650]

I instantly knew it was a Ford tube after working on countless old radios. This is a great example of modding a tube amp for guitar use! Bravo Brad! Your wife must be a saint to let you get away with storing tubes and such in the laundry room. I don't feel too bad about my collection and how I store it! Thank you for sharing not only a look at how to change an amp to play guitar through but a look at the "Mad Scientist" and his work shop! Thankz

[@TheGuitologist]

Am I crazy or have I seen tubes labeled "Ford" also?

[@audiotechlabs4650]

The capital "F" gave it away. Never saw "Ford" on a tube, just FoMoCo. Thankz

[@jhs5150]

GM made tubes too. I have one I pulled out of a '78 2204. Delco comes to mind ;-)

[@dzfh98]

For knobs I use a plastic clip removal tool for a car, they are at harbor frieght, it slips behind and pushes the knobs straight out.

[@NitroModelsAndComics]

Another great circuit Brad. You keep making them better brother.

[@TheGuitologist]

I will probably keep this one a few more days and tweak around on it, but it's mostly there.

[@maxwethersfield]

I agree with you about Sears-they should come full circle and sell power tubes and various other parts and accessories online for guitars and amplifiers (maybe even reissue some old Silvertone gear). Sears' new business model could be a cross between Amazon and Carvin.

[@TheGuitologist]

It would be nice if Sears could survive and make the transition. I was reading some WSJ article not long ago about one asset they have in abundance is real estate! They could re-tool and update their online presence, strategically convert their retail space to warehouse space/limited retail space and could be positioned to survive.

[@jhs5150]

They sold their credit card wing to Citibank several years ago, SMH. It seems to me that was the only division making money ;-)

[@sandrawinkler8965]

Exactly. Just combine the two names and you have ARCIN! (with a hard C)...I hear their commercial now "Tired of the old way? Start arcin and get a real charge in life!

[@AMStationEngineer]

Somewhere, I have a 1965 DeVry Tech 'amplifier effects generator'. If memory serves, the circuit used a pentode, triode, and a 5U4 rectifier. I remember seeing an R/C cascade, switched by the pentode, and receiving a feed through two or three coils (used for delay/feedback?). That circuit would work nicely with a simple, but nicely effective amp like this.

[@TheGuitologist]

Sounds like a good candidate.

[@bradleyard4195]

Add an A/B box, and you essentially have a footswitchable two channel amps, using the "high" input as a clean channel, and the "low" input as a high-gain overdrive channel. I dig it!

[@andrewgillis8572]

@The Guitologist oh yeah my question answered, at long last: grid stop/grid leak/input resistor are terms referring to same item in path - and Astatic mic users IE harp players are advised by the company to seek 2 meg ohm at this location, or risk loss of bass response from ceramic or crystal cookies - as I understand one of the Bassman inputs (aimed at upright players with pickups way back?) has this very feature - this true? the cookies I mention are the PAFs of the harp business - MC 127 and MC 131.

[@TheGuitologist]

Thanks ffor the comment. I'm no expert in harp playing, but I do know there are some highly sought after mics.

[@johngeddes7894]

Love seeing complete remakes turning what may have been trashy into a really desirable guitar amp. Creative circuitry. Now I’m stoked!

[@blackfender100]

Awesome Job Brad. a very nice Amp now It's the bomb great classic rock sound.

[@jabelsjabels]

Yeahhhhhh another conversion!! Perfect evening relaxation viewing

[@TheGuitologist]

Relaxing until you get to the motorboating amplifier. :D

[@infinitesimotel]

This amp would sound perfect for punk and garage. Would love to hear the cabinet miced too, excellent job. Loving those Teiscos hanging up in the back :D

[@stephenquail3168]

Wow you really made it voiced sweet.That capacitor substitution device is really cool man.

[@TheGuitologist]

Makes things a bit easier.

[@Soldano88]

That’s F’ing awesome Brad🔥

[@irtazamehdi2856]

What a collection!!! Fantastic!

[@Brandon-sr8qd]

I actually love the sound of that thing after you put the new tubes in, before you replaced the innards. Sounds broken, in a good way.

[@Brandon-sr8qd]

Minus the scratchiness and cutting out of course....

[@TheGuitologist]

It was in rough condition at that point. The cap can was actually getting hot to the touch, never a good sign, and was also literally leaking electrolyte in bubbles.

[@Brandon-sr8qd]

The Guitologist Of course this thing needed the repair, I just found it interesting I actually liked the sound! Appreciate the vids.

[@TheGuitologist]

The thing about tone is every just just about has a place. In the right song in the right mix, it could be magic. If you isolated down half the classic tracks everyone fawns over and just listened to the guitar alone, probably 5/10 would sound like shit on their own.

[@Brandon-sr8qd]

100%. Bedroom, live, and mix sounds are completely different and I found that out the hard way when my solo came in the school talent show. ;) Mids are your best friend when you're a guitar player.

[@TimmyP1955]

As one side of the OPT primary is grounded AC-wise, thus the little cap is a HF filter methinks.

[@gerryb4540]

Another good job you have a great channel here Thank You.

[@lroy730]

Great Tone after all your Mods Nice Work !!! Running a decoupled heater circuit into the signal is an attempt at noise reduction. In theory It works If done correctly . In noisy Marshall's I use (Inverse Feedback, See RCA Tube Manual) for noisy gain stages, has nothing to do with heater circuit . A tip on the Preamp, High Gain Stages is Use a about 100 to 200pF cap from Grid to Cathode same tube to null Blocking Distortion. You can have all the gain you want if you control the noise.

[@TheGuitologist]

Thanks for the comment. I'm aware of that cap trick. Another is to run a small value cap from plate to grid or plate to ground. Then you can bias the stage closer to the edge without going over it.

[@stratcat250]

Looks like you didn't want to put it down when you were done. That's what happens when you find great tone. Great job!!!

[@brittisaacrossman]

Wow Brad. That was rough going for a bit, but what a killer finish! I knew you could do it, but holy crap that is a gnarley 5 watts! Totally unexpected - imagine bringing that to an open mic, hah!

[@Dlokey4315]

You took a lump of coal and made a diamond. You do a great job on restoring these antiques and newer stuff too. Keep up the great work and I will do my best to keep watching. ✌💀 Rock On!

[@gloriouspeanut]

That thing really rips! Great sounding speaker.

[@TheGuitologist]

It's doing its job, but honestly it's probably the first thing I'd change. A 10" would really be nice in this. Would add some balls.

[@gloriouspeanut]

The Guitologist Sounds great on the recording though. Is it worth anything to you? Would you consider selling or trading for that speaker? I don't have a good 10" but probably some other stuff you would want.

[@baronvonchickenpants6564]

Awesome playing!!!! And what a tone

[@chatboxguy3363]

I believe that it was a previous shipping or moving experience the Transformer bent Guitologist. If you study the screw and the joint area is that it dried out and rusted a bit. Its solid, but it can settle metal peaces if there stuck together for a long period of time.

[@Oobidoobi]

Dude, your wife must be incredibly understanding and forgiving. After seeing all of those rooms packed with parts and equipment, and the LAUNDRY ROOM?!, if she lets you get away with all that, she's a keeper!

[@TheGuitologist]

I've held onto her for 11 years, miraculously.

[@50gary]

Brad,.. that was an amazing effort, at the beginning I would have guessed other techs might have binned it. The Silvertone Mojo is strong even in this amp. Rocks very hard, loves the P-90s Great video. super crunchy 5w. I have a Silvertone "Reverberation Twin Twelve" unmolested with Tremolo and the original wooden foot switch. It does need some caps. and the three prong grounded power cord.

[@ovation99]

Man you have some patience and then some. But it make for interesting and inspiring videos. Keep it up, great stuff.

[@jackallen6261]

This thing sounds AMAZING! I have an old Harmony and an old Kay coming in from ebay as I type...I hope maybe I can get one of them so sound somewhere near as good as this! Thanks for sharing!

[@jacobdowler1]

killer amp man! i hope you keep doing these videos, repairs and conversions Brad, thank you for the great content! i have learned a good amount, maybe i could get into this hobby someday perhaps:) i have always loved Guitars and amps, electronics in general . Rock n Roll, Blues, Jazz, are my favorites Funk and HEAVY shit as well! Whatever sounds good with good sound quality is what i like.

[@mstecker]

You have every right to wear that Superman shirt after that feat. Really great work!

[@RealGengarTV]

Man, a cool mod would be to change one of the inputs to a foot pedal input so you could select channel by foot and not have to physically change jack.. awesome video as ever 🤗 thank you for the informative and interesting videos

[@mikemoyercell]

that is the exact amp my silvertone reel to reel has. also FoMoCo is Ford Motor Company. They made tubes for car radios.

[@robertinfante5222]

Slip a piece of cloth behind the knob and pull with that. It'll spread out the force behind it when you work it out. Same deal for old car trim that you can't replace.

[@cliftongardner4367]

My gosh that sound with the P90... Juicy!!

[@jamessurface9100]

Hey Brad, FoMoCo was a parts division of the Ford Motor Company back in the day. If memory serves, they dabbled in electronics also. (that was a long time ago)

[@jraimondi]

Nice work...its a beast cranked!

[@johnthrelfall5]

Good old 6V6GT single ended output 4watts same as first guitar amp I built!

[@YC-757]

Your works are amazing all the time!~

[@keithmangold2263]

i had an amp...that was 2 12 in spks each mounted in open back cabinets that buckled together...this reminded me of that. the tube amp itself was a challenger 33 and had a mesh metal cover and it fit halfway into one cabinet, then into the other as you buckled them (for transporting) ...and the inputs (3) were all the type you have to screw on an adapter to make it 1/4 inch..( i think it was made for mics with a built on cord that had a threaded end on it...very old school..) was a great amp for beginning...but only got drive when turned up. no pre drive. and then it was too loud for bedroom practice...good for band practice....maybe different tubes would have helped. wish id known someone like you who could have tweaked it right. :)

[@j_freed]

Thing sounds wonderful.

[@anthonyf4439]

Gotta love that LP junior.

[@jmoffitt36]

Wow, really like the Fuzz sound to it.

[@fortj3]

You practically have a warehouse of cool stuff. I'm definitely a little envious.