The Amp Garage

martin manning wrote: ↑Sun Apr 24, 2022 5:11 pm For example, originally there was no QT, as Ronald didn't see any value in it. I lobbied hard for that, and even provided a drawing to lay out the form.

Wow, that's crazy. I use that most feature most frequently by a long shot.

Stevem wrote: ↑Sat Apr 23, 2022 8:53 pm I would go with the 10 watt Hammond 123DSE if you will someday run two in parallel.

Yep, what I was thinking as well.

Stevem wrote: ↑Fri Apr 22, 2022 11:13 pm Any Ot that works for 6v6 will work fine for a 6AQ5

Thanks stevem. The replacement xformer for a 5F2 Hammond sells is spec'd at 5W. I suppose something around there will work alright.

I'm planning a 6AQ5 single-ended build. I bought a small stash of 6005W planning to make something, finally getting around to it. 6AQ5 datasheet Finding xformers has been more difficult than I expected, here's what I'm thinking; PT : Hammond 261M6 215VAC secondary (non-center tapped) @ 269mA - plent...

My recommendation to EVERYBODY is to go to ebay and buy yourself a good used General Radio or Powerstat variac/variable transformer and just try to forget you have one of those red Chinese gadgets that vaguely resembles a variac. With many of them selling for under 100 dollars, you really don't hav...

Never going back after switching to teflon. Burned insulation is a huge pet peeve.
Tube depot has some good 18/20/22ga PTFE stranded wire. Or just ebay.

Looks great pal!

sluckey wrote: ↑Wed Oct 06, 2021 1:32 am What??? You bought a DSO before you bought a memory stick? Steal one from your kids.

HAH the only reason I can afford this oscilloscope is because I don't have kids!
(Just kidding, this scope is actually really affordable)

it happens :D amp should be ok now? p.s. humm/noise level is satisfying? enjoy the amp! Very ok, very loud. Here is a the output now across an 8Ω load. This is just before clipping: Photo Oct 05, 8 17 59 PM.jpg and before you yell at me sluckey, I actually don't have a flash drive... EDIT: yes, I b...

Found it, thanks bepone and stevem.
I knew it was going to be something dumb.
For some reason I decided to use buss wire for the grounds on the output jacks, and the wire was laying across one of the little nubs for the tip.

I knew there was a way! Thanks sluckey. I stuck the scope on the load resistor, as expected there's very minimal output. I couldn't grab a pic, it was about 1.5VAC P-P before clipping, and very jagged and ugly. Also the bias voltage seems low for the idle dissipation? I was reading -37V, and that wa...

Here are some scope pics of the preamp (preamp and master volume both at 5 for all pics). Schematic again for reference: schematic Input is a 1kHz sine wave at 500mV P-P: https://imgur.com/g5L7Ahe.jpg V1, pin 2: https://imgur.com/gj0aR1U.jpg This is right after the coupling cap coming out of V1; pin...

When your using a scope in any part of a circuit that has DC voltage on it you need to couple your probe thru a .01 @ 400 to 630 volt cap so as to not harm the scope if your probe has no built in cap, just resistance settings. Correct me if I'm wrong, but don't most scopes have an AC coupling mode ...

I appreciate both of your inputs, but let’s hit the brakes. I’ve got a new scope coming tomorrow or Tuesday, I will return with images/video. I have a suspicion I may have some issues in the preamp, I was briefly probing around (while my 2213 was still triggering) and the input into the DCCF was ver...

There's nothing wrong with your bias supply. The current requirement is almost nothing. Nice looking bracket for the bias pot. I notice your grounding relies on the mounting screws for several of the terminal strips. But I don't see that you removed the paint down to bare metal on the chassis. If t...