stromberg - carlson no.20 amplifier X-former

[stingray_65]

After my recent sucsess with building a 5E3 amp (thank you every one who guided me) I decided I wanted to try building a little more complex and challening guitar amp.

To add to the adventure I decided that cost woud be a factor in the design.

Besides the tubes the PT and OT are my biggest expense.

Long story short I scored an ancient PT on ebay REAL cheap.

It has a lable showing the tube layout on the chassis and it powered 2 6L6's so I knew it would have at least enough current for about a 30-40 watt amp.

I'll check the voltage out with no load after the holiday.

What I want to know is how much current do I have to work with on the secondary side.

How can I measure this?

I have the list of the tubes it powered so maybe I can reverse engineer from the tube specs as to what kind of current draw they had.

The tube compliment is as follows (1) 5U4-G (2) 6L6 (1) 6N7 (1) 6J5 (2) 6SJ7

I'm thinking of building something like a 5E5 Pro, but with a single chanel and a tone stack.

But if I had enough current I would love to build something like a Twin with (4) 6L6GB's

Any help woud be GREATFULLY apreciated!

thank you
Ray

*edit*

WOW I was throwing out the packaging and the seller included the lower plate that has the schematic on it. It doesn't have specs on the transformer but it is definitly a push pull amp. The heater tap (6.3v) is not center tapped, the high voltage taps are, and it looks like it has the 5v winding for the 5U4G

[stingray_65]

well price paid minus .09 per lb at the scrap yard i'm only out $20

[scole]

hey stingray, hows that stromberg going? i found an old stromberg 10 in the shop at work. i asked my boss if i could have it, he said ill find out. that day after lunch it was on my desk. im planning to turn it into a guitar amp one of these days.

[tboy]

I have a pair of those somewhere. I think the model is "Signet 10" if I remember right. It would make a dandy little guitar amp, but I might use 'em for HiFi since I do have two.

[tboy]

Tell us what happened Sting', is it dead?

[stingray_65]

well the tranny is dead

at first I tried to find resistance between all the lead and only found two pair

I then hoped for corrosion on the leads and found that when i polished the ends and tinned them only found a center tap and one more pair.

unfortunatly none of these were the black primarys

so I hooked a pig tail to the primarys ( or what i thin are the primarys) and plugged them into my variac and SLOWLY ceanked the voltage with my meter on the red wires that read good initaly

NUTHIN

oh well

My Karma did swing the other way this weekend
in this tiny sleepy town i live in there are 6! HUGE! antique stores. while looking for a wooden cigar box to make a cigar box guitar,
i picked up 1959 portable Zenith record player that worked when you jiggled the bass knob for $12

put the chassis in a box i made out of baltic birch used the old wheat grill cloth and to keep things on the cheap i used blue denim for coverings and an old leather handle.

i did spend $6 at radio shack for a neon indicator and a 50k linear pot to replace the trble pot.

i needed a 25K audio taper so i used the 50K linear and ran a 47K resistor across the two outer lugs, it aproximated a linear taper and sounds AWSOME

oh yeah! it had 2 zenith 12ax7's dated 13th week of 59 ! wow do they sound fat in my 5E3

OH! and at the other store while talking to a kid about amps and cigar box guitars he sold me his "beat up" les paul for $25

its a gibson/baldwin epock and needs a new selector switch and a drop of solder on the switch, but other than that it sounded pretty damn good!

Loose some win some