The Amp Garage

Phil_S wrote:Something to do with the chassis bolts flexing the chassis? It could be ever so little, but enough to trigger something.

update: If I cover the top of the chassis with a cardboard sheet, the tremelo stops.

Guy brings-in his silverface Deluxe reverb. Reports that the tremelo stops and starts while switched-on. I listen and hear what he's talking about. So, I take the chassis out and put in on the bench and test the crap out of it and it works perfectly. So....I put the chassis back in the cab, and the ...

Hello Everyone, I won't be so bold as to suggest this could be an error, but I'd appreciate any and all comments on this: I am curious about the voltage across V7 in the SSS #002 schematic. I don't see any reference to tube types in the schematic, so I will assume V7 is either a 12AT7 or a 12AX7 (a...

Cantplay wrote:Then it acts as first order high pass filter.

The choke is eating some of the low bass.

John

Yeah, I think this makes sense.

thanks

The two speakers are connected in series:

+
-
+
-

with the choke between the top "+" and bottom "-"

Is it field coil speaker? There are only two wires headed-out of the OT to the two speakers. Then, this thing is mounted to the woooden cabinet, has two wires, one to each speaker. So, there is not separate power to the coil, it is simply connected between the two speakers.

I have an amp that I developed using the Winged-C's and it put out 40W before any visible clipping (on the o-scope). With a new set of the TAD 6L6GC-STR's I can only get 35W. I biased the TAD's at 20 Watt plate dissipation, same wattage as I had biased the Winged-C's To me, it seems the TADS are not...

Montgomery Ward Airline amp. I have one in the shop for repairs. There is what looks like a choke mounted between the speakers inside the area of the cabinet where the speakers are. Inside the chassis there is an output transformer, with two wires headed out to the speakers, ie. looks fairly standar...

what is the skyline tone stack? The one with mids control with separate path to ground (separated from the bass control)?

in my case, grid voltages being pulled-up all over the place!

Everytime I work on an old amp with these Sangamo coupling caps they leak like crazy.....In an old Sears (Silvertone) 1474 I was just working-on all of these caps leaked, every single one. Blech.

I just tried the amp with another OT (different manufacturer). With the new OT the trim point for the least 2nd harmonic is more toward the middle of the trim pot range. With the previous OT the trim pot had to be turned all the way in one direction. So, this is interesting, my measurements of the O...

I tried driving the secondary and measuring the voltages between the two halves of the primary. They match to within 1%. I checked the screen R's, they are the same for each of the 2 output tube tube sockets. I also scoped the voltage of each screen with the amp at max power. The screen waveforms ar...

How about putting a signal into the OT secondary and then see if the two halves of the primary will cancel out on your scope? I don't know how you measured the voltages to determine the turns ratio, but the response may not really be the same on both sides. I drove one half of the primary (between ...

thought I'd re-open this useful thread! I am trying to figure-out something about this issue. So, I have a 12AT7 PI, 6L6GC outputs into a Hammond 40W OT. I measure the OT turns ratio from each half of the primary to the output and they are very very close. I put in a 300Hz sine wave, and from the se...