You won’t really hear any difference with the impedance switch. But maybe you have that wired incorrectly. The round eyelets should be what you are switching (green, yellow or white) and the odd shaped one (on the same side as one of the round eyelets) should go to the output jack. I think thats how it goes if I recall correctly.
Feel free to…[Read more]
The next step is to super check all of your grounds. In particular, the panel mount pots. Make sure all your grounding is solid.
After that, I would take some voltage readings and let us know what you get. Pins 1 and 6 of the tube should be around 140-160V. Pin 3 on the power tube should be around 350V, Pin 4 around 300V.
The currently available power transformers don’t supply what is called a “center tap”. That was a green/yellow wire in the instructions. The 100Ω resistors are there to create an artificial center tap. This is done by attaching a 100Ω resistor from each green filament line to ground. I usually attach it at the 2 pilot light terminals and ground i…[Read more]
That is great! What was the change that made the amp louder?
I really love some of the builds from Tiny Zotolla: https://amzn.to/2OsZmdc
His AC30 Top Boost designs are pretty great sounding from Volume 2.
From what I recall the 290AX is the one you want. The 22772 has 2A for the filament so that should be fine there. You’ll need about 70mA on the secondary so that is good too.
Sorry, just seeing this as we has some email issues. Did you figure this out?
Do you have any other specs on it? Attached is the requirements for the standard OT.
Sorry this is embarrasingly late. The brass plate is really a grounding plate. I typically make a ground bus out of wire and solder it across the back of the pots, then solder all the ground points to that. The end then goes to ground at the three terminal strip. You can also do this with a ground wire. The newer kits come with a strip…[Read more]
TAN-ADMIN replied to the topic Input resistors and OT choice of wires for impedence in the forum 2 Stroke Amplifier Design and Building 3 years, 12 months ago
For the schematic vs the layout, you are absolutely correct. The extra 1M resistors on the schematic are for the pop suppression modification. We include those parts in the kit as a courtesy. Its a nice modification to make, but its not in the book and the layout is straight from the book.
For the OT, I usually do GREEN and YELLOW.…[Read more]