The Amp Garage

Kinda like this, but not exactly? This is a modern one; I doubt they are compatible with the old standard.

MPM

Described here:

http://www.freewebs.com/valvewizard/bridge.html

MPM

Another option that might be worth a try is the updated Fender trem circuit from the Vibrolux and Vibroverb reissue amps, which can be seen here: http://www.lynx.bc.ca/~jc/tremoloCircuits.html Scroll down to see a link to an except from the schematic. The feedback comes from the follower's cathode, ...

...I'm doing a 100W 6L6 BM so current draw will be in the neighborhood of about 4.5A. Using the calculator and reading off the, "External Layers" column, I get an required trace width of 2.39mm. Should be enough. Also, if I were to fill in the copper traces with solder, I'd think current handling c...

Some good stuff on 1) here:

http://circuitcalculator.com/wordpress/ ... alculator/

Looks like 1-oz x 3mm (0.125 in) width traces should be good for close to 4A on an external surface. Maintain that as a minimum and I think it should be fine, no?

MPM

Nice work! A couple of questions, if you don't mind: How much of the circuit is modeled? Sounds like you have at least the whole clean section since you say no NFB is included. It would be nice to establish a reference case for the standard pre-amp circuit. What are the setting of the switches (Brig...

I'm interested too... PT and/or kit. Is there enough room to squeeze a choke in there?

MPM

I think that's it, Bob. The small capacitance formed between the parallel cathode and plate leads acts like the small-value snubber cap often seen soldered from plate to cathode. Since the cathode resistor is bypassed to ground with another cap, this trick shorts HF on the plate signal to ground. MPM

Agree with ya.... - The high plate (220K, 3.3k + 150k, 2.2k) used 5uF - the low plate used 10 uF Hence, explaining the difference in low end (but not the overall volume difference) So you did (partly? mostly?) compensate for the resistance changes. The 220K stage break point is about the same, and ...

- And the high plates had more low end that the low plates. If you don't change the value of Ck or the coupling cap (Co) to the following stage, and you double the values of Rk and Ra, then the low frequency roll-off at -3 dB for Rk-Ck and Zo-Co will both be halved. That might explain the "more low...

In the spirit of discovering why and putting a face to a name, I made some plots to show what happens to the load lines and operating points as the plate load is changed. The first plot shows the anode load lines for 100, 150, 180, and 220K Ra on a representative set of grid curves. There are also t...

The Valve Wizard is using "conventional flow" notation, where the charge carriers are assumed to be positive, and current flow is from positive to negative. In "electron flow" notation, the actual motion of (negatively charged) electrons is observed, and the flow is from negative to positive. Either...

Sorry to bump this... I have made a limiter (finally after building five amps lol). Now I put in a 60W lightbulb. I turn on the main's switch and the bulb grows bright. It stays like this. I think this is ok as there are no tubes in and all that is in the circuit is the first filter cap. Should I f...

http://www.aikenamps.com/

Then go to Tech Info, Advanced, and scroll to the bottom of the page.

MPM