Converting 1956 Silvertone Tape Recorder into Guitar Amp

[mrjoncruz]

I found a 1956 Silvertone Recorder with a 12au7, 12ax7, 6x5gt, and another tube for the output I assume.  I could not find a label on.  It has one volume and one tone knob.  I plugged it in and the fan worked, and all of the tubes lit up and had power.  I realize I need to test the tubes and transformer (and maybe much more) but assuming it all works, what modifications must I do to have a functioning little chassis?  There is power going to the fan and reels, and 3 lines (two black and one red) going to the tape heads.  It does drive its own damaged internal speaker which I want to take out and bypass.  A schematic is pasted to the inside but is damaged and missing about 20%.  I can post pics of it later along with pics of the item itself.  Is anyone familiar with a conversion like this?

[tubenit]

Silvertone was made by DanElectro at some point ......... so maybe look at the single ended DanElectro schematics?

All the Bogen type conversions that I did involved gutting the amp and then using the trannies, sockets and chassis to build something I actually wanted.

I just drew up my own schematics and layout.

Having said that, perhaps this amp would convert to a nice VibroChamp style with the two 12A_7 sockets, 6X5 rectifier and perhaps a 6V6 or EL84/6BQ5 power tube.

It's only got one power tube, correct?   You can probably parallel some terminals strips to mount components which is what I did on the first several Bogen conversions I did.

With respect, Tubenit

[tubenit]

Here is sort of a Silvertone Vibro Champ idea that is single ended with a 6V6

http://www.el34world.com/charts/Schematics/files/silvertone/silvertone_1449_1457.pdf

With respect, Tubenit

[PRR]

> Silvertone was made by DanElectro

Sears used the SilverTone name on a LOT of stuff.

I'm guessing a tape recorder had too much mechanical etc to be up DanElectro's alley, but WebCor and Brush and several others were pushing tape machines down-price, and would be thrilled to get a contract from Sears.

IMHO, a low-price tapedeck is an ugly candidate for conversion. The wiring is a total mess. You can bulldoze it out, but do you have the experience to re-purpose it without a major melt-down?

> I realize I need to test the tubes and transformer

Why?

Just see if there's 300V in there somewhere. The tubes are cheap types, and you MUST have spares or debugging can be frustrating. The capacitors, you can just assume all are past their peak flavor date, or will be an hour after their first power-up in 40 years. The resistors are the very cheapest sort, good for 90 days. While you'd think the heater wiring could stay on the sockets, the sockets are also cheapest-type and may end up being replaced just for tarnish build-up and lame tension.

[mrjoncruz]

It cost me $5.  Its not a big deal.  If it works, good enough.  Thats too serious of a reply, honestly.

[mrjoncruz]

The tubes arein fact not cheap types.  Being a beginner, I just learned that it has a black plate rca 12ax7.  I am glad to know you were wrong.

[eleventeen]

It's certainly understandable that you'd expect PRR to be able to see the insides of your 12AX7 and know what brand it is. Yup. A 12AX7 when I was growing up was about $1.25 and nobody cared if it was a CBS or a Sylvania or a GE or a long-plate clear top oval getter or anything else. You diss a tremendous amount of experience with your snide post to PRR. You asked, he answered.

He's giving you good advice. Consider that possibility. Unless you know better, or think you do.

[Willabe]

You diss a tremendous amount of experience with your snide post to PRR. You asked, he answered.

He's giving you good advice. Consider that possibility. Unless you know better, or think you do.

Yep, PRR was only trying to help you. It is WELL documented here at this forum (and others) that he knows of what he speaks from not years but decades of hands on experience. And by that I don't mean carrying around gear from gig to gig or using gear in a recording studio. He was inside fixing and modifying them.  

It's certainly understandable that you'd expect PRR to be able to see the insides of your 12AX7 and know what brand it is.

Eleventeen's right.
 

but WebCor and Brush and several others were pushing tape machines down-price, and would be thrilled to get a contract from Sears.

IMHO, a low-price tapedeck is an ugly candidate for conversion. The wiring is a total mess.

I think PRR was saying it probably left from the factory with the cheapest tubes they could source at the time for price point in the market? Also 12AX7's were a simple small bottle triode in mass production by a lot of companies through the years so plentiful and cheap over all. So someone swapped in an RCA at some point, OK good for you. That doesn't mean his over all point was wrong.

Not nice to nip at the hand that feeds you.


            Brad      

[eleventeen]

"I think he was saying it probably left from the factory with the cheapest tubes they could source at the time for price point in the market?"

Maybe. Back then a 12AX7 wasn't anything special, and an RCA 12AX7 wasn't anything anyone cared about vs a Sylvania or a GE. I just took apart a 1959 Conn organ with 36 qty 12AU7's in it. Too bad, low value tube. There were about 5 different flavors. All but 2 or 3 were branded "GC Conn", eg; OEM parts. Some of the RCA's with the octagonal branding were of Sylvania manufacture (there's differences in the insides and the tube-type as printed on the glass envelope us toobists would recognize) and some of the Conns were GEs. OTOH, if for some reason the little amp was tubed with ECL82s or EF86's (possibly having been built in Europe) then those would be a tad more exotic and a bit harder at this time to source. We all know that on occasion, RCA-branded tubes were made by Syl and vice versa. This was stuff nobody cared much about back then.

[terminalgs]

I am glad to know you were wrong.

Wha??

Thats too serious of a reply, honestly.

WTF?

on other forums,,  this BS would be replied to with 'move to ban' with +1's ++1's as other replies..

mrjoncruz,  so you don't want the advice you've asked for, why don't you just regale us with your plans for this device, and tell us how you'll do it, and how it'll work.

I've worked on several old tape recorders, I've got a few here, including webcors with your tube complement, I have schematics, and I might be able to offer some insight, but with the strong likelihood that your reply would be little more than a dismissive snide remark, why waste the time?

[Meat_And_Beer]

In the era your tape deck was made and much after, cheapo Chinese junkeroo tubes didn't even exist like they do now. Manufacturers used the tubes available at the time, which are now regarded as the best you can buy. At that time, they were everywhere. You got a good tube by default.

In all honesty, I made a comment slip up very early in my time here. No going back, and I'm sure I lost a lot of credibility and respect. Bums me out. But you might as well have flipped the bird to some of the most respectable, talented and kind people on this forum. You asked, and you got super excellent feedback. Too bad you didn't like the answer.

A guitar amp out of a tape deck?? Nah. I bet it'd make a nice tape deck, though.

Or, with a very simple and easy mod, you could plug an iPod, or similar device into it.

[eleventeen]

There are unquestionably Champ-type possibilities out of a crappy little tape deck amp, there shouldn't be much question about that. The few issues are: Enough B+ for a Champ, or near? Transformer mains supply or line-rectifier/hot chassis? And, is the sheet metal of the chassis so completely cut away (so that some goofy mechanical lever thingy can poke into it)  so that it doesn't make a very safe box? Or...is it just built on a primitive "L" bracket? Maybe that isn't a problem if you're gonna retain the existing box for the Champ conversion. When such an amp was built in 1956, the price of the whole amp, parts and labor, was quite probably less than the today-cost of a legit power transformer for it, even a puny one like a Champ would use.