The Amp Garage

It seems to me that the Aikenamps site says the same thing I am saying: "The third input is not so obvious; it is the lower end of R6. If a signal is input at this point, the phase splitter will produce an output signal on each output that is in phase with the other, rather than 180 degrees out of p...

I think I made all the changes before the lasts simulation. I also found the FB resistor was 1000K not 100K and changed that to agree with the Express and Liverpool schematics. If feedback is to the cathode of a LTP from the output transformer secondary, it can not be NFB for both triodes. It has to...

I've read from page 60 back to the begining, and a good bit from here back but still haven't found some answers about the phase splitter. However a little analysis and I think I understand what is going on. The disparity in output from the LTP is intentional and is caused by the feedback. It is not ...

It appears to be a three position switch with a tapped inductor. The blue wire connects to the switch common. Since there are only four switch terminals, the off position probably does not have a terminal. Given that that is the case, the white wire connects to the next to fully CCW position of the ...

I could understand a little imbalance, but this is 6:1 I've never seen this much imbalance in an LTP. I guess the only thing to do is throw one together and see what it does. I found I have an old 6V6 output transformer in my parts stash, along with a Stancore PT8401 that is about minimum for buildi...

Hum can also be casued by bad (old) filter caps in the power supply, insufficcient filter caps in the power supply, poor wiring technique, poor shielding (especially high gain stages), and not shielding the enclosure (no bottom on the chassis). Then there are ground loops in external wiring and I'm ...

Cushman (basket case) 1968, Ariel 500 Red Hunter (basket case) 1973, Triumph 650 (basket case) 1974, Honda 175 (got from my dad) 1982, HD 1975 Ironhead Sportster (basket case) 1999. Kind of a trend to rebuild basket cases. The chopper was a full custom including batteryless solid state ignition (my ...

The 120K was set in place of a 100K when the simulation showed an imbalance in the output of the two sections of the phase splitter. I suspect a simulation error but am not sure exactly what is wrong.

Thanks on the fb. It is connected wrong (early am this morning/last night). I'll move it.

Cryillic letters don't show in title so I changed it. I owe a buddy of mine in Canada a favor and knowing he plays guitar I planned on making him an amp. I had already started a design when I found this site and decided a lite version of the Trainwreck Express (Liverpool) would be a nice gift. I do ...

I think that Randall Smith might object to Trainwreck using the name "Express" as Mesa has that name Trademarked. http://mesaboogie.com/Trademarks/Trademarks.htm Pot, meet kettle :wink: Differential Feedback Amplifier - Ha..ha..ha..... that one cracks me up. I think the Air Force has the F series. ...

The term Express goes back probably a hundred years.

577 Nitro Express - 1898 Holland and Holland Great Britan.

Kind of hard to trademark a single word without applying it to a specific product. Even then it is difficult to defend unless you have deep pockets.

I was aware that they could be run in triode mode as deflection amps at 315V with up to 1200V peak output, but didn't realize they would hold up to near 400V in pentode mode, much less 450V.

I had never seen that in a stereo amp.

Thanks.

Greetings. Great site and wonderful documentation on the TW Express. One question please? With regards to t he schematic, shouldn't V4 and V5 be "EL34 or 6L6" instead of "EL34 or 6V6"? The 6L6 is a closer match to the4 EL34, and the 6V6 is not rated for the plate voltage present. Well, that was two ...