So I found this Gibson G35 amp chassis on ebay.
Seller said non-working chassis only, no cab or speaker.
Power cord and speaker wires cut.

Has a cute little Accutronics reverb tank. 

As usual I installed a 3 wire power cord and clipped the death cap.
Hooked up a speaker and it fired right up and sounded way better than I expected.

I wonder if the guts would fit in the Sears amp? 

Thanks Phil! 

Yes, this old Silvertone guitar is near mint. A little checking on the finish but not much else.
I have a second one, but it is much worse condition tho still playable.

I started collecting these 60's 70's cheap (when they were new) guitars a while back when the market was in a lull.
Prices were good and some of them are actually decent pieces when setup right.
Usually need a re-fret tho. Stock frets are often very low and flat, even when they were new.

I suspect this Silvertone was made by Teisco, or more likely Kawai. Overall quality seems good for a budget student guitar.
Nice straight neck.

I know what you mean about short scale guitars, tho I rarely play above the 12 fret since I am Rhythm guitar in our band.
Actually, i prefer short scale as it suits my small hands, but my main guitar is a Tele.
I like the Fender 25.5" scale for the sound, but the short scale is way easier for bar chords. Less string tension.

About the amp... yes... I have a plan. 

Will post more soon.

Quote from: J M Fahey on October 18, 2017, 04:14:46 PM
Cool.
You may "spread"  the adjustment range.
Say now you have to set the 100 ohm trimmer to somewhere around 62 ohms?
Replace it with a series combination of fixed 47 ohm resistor and 25 ohm trimmer, you physically widen the sweet spot 4X .

If you dare: use a fixed resistor 5 ohm below needed value , in series with a 10 ohm trimmer.
Now THAT will become a "fine adjustment".

Although the main problem remains: lack of thermal tracking.

Thanks much J M!
Ya, thermal tracking would be great.
I just have to make sure I set the bias when it's good and warmed up.

"My" Sears amp came to me non-functioning and missing the reverb tank.

Here is my very first guitar that I got with the amp.

I never thought I'd see another one of these! 
This is exactly like the very first amp I had in the early 70's.

Made in Japan, it is exactly like many of these "Mini Stack" amps that usually came with a 2X8 speaker cab.
I own a few of these, Teisco, Audition, Kingston, Domino, plus I've seen some with other names, some with a 1X12 speaker in the same size cab like the Wabash.

This Sears did not come with a speaker cab, but I have a spare cab that I found on Reverb.

They all have the input jacks on the right, with the exception of the Teisco.
Circuits are not all the same, but there only seems to be 2 different ones.

I found another Hohner schematic, this for a 1040 model.
Not the same as the 12R but the output section is the same with the two 100R bias trimmers.
I adjusted the bias as per the instructions on this 1040 schematic.
The adjustment trim is very touchy so I may install multi turn trimmers at some point.

Looks innocent... Packs a Punch! 

Stuffing a 500 lb amp into a 10 lb space... well... that's a slight exaggeration...

The heat sinks for the TO-3's are 1/4" thick aluminum angle stock.
At full volume playing for 20 minutes the transistors are barely warm.
This thing is loud and punchy.    <3)
Has a thick saturated distortion at full volume. Very usable.

So here's why I call this a Frankenampmonster.

I'm gonna stuff the guts of the Hohner into this tiny Teisco Checkmate 21.  :duh
The original Teisco has maybe 2-3 watts at best.

Just eyeballing this I think I can make it work....

With the Hohner chassis on my bench I replaced all the electro caps and added a 3 wire grounded power cord.
Also clipped out the death cap.

Playing it thru a 1X12 sealed cab loaded with a Celestion G12H it sounds pretty good.
Some minor hum that got better (less) when I adjusted the bias.
The bias trimmers are glitchy and I need to replace them.

Here's the guts of the Hohner and a schematic for a Marlboro G40R.

The Hohner has some minor differences in part values, plus a second 100R bias trim and 220R on Q10.

Sorry about the poor schematic, it was all I could find.

I picked up this Hohner 12R on ebay.
Thought it looked cool and it was cheap. 

When it got here it was damaged in shipping, 
and I ended up getting a full refund including the shipping. 

Pulled the chassis out, with the idea that I might repair the cabinet or make a new one.
The amp still worked and didn't sound half bad.

With the chassis out of the cab I found "Marlboro" etched on the circuit board and Marlboro branded TO-3 output transistors.
A little research an it seems Marlboro Sound Works made many amps that were re-branded,
Hohner
Paramount
and probably others.

Looking at the chassis on my bench... ideas began to form... and I abandoned the idea of fixing the cabinet....

More to come later.... 

Grogg say "lightbulb limiter goooood" 

Yes lug 1 to ground.