The Amp Garage

Here you go! UP Bassman w/Gain as it looked at power up. Played it for a few weeks then started tweaking circuit. (FYI, component values stayed the same, only their composition changed). 58141B8E-CB33-4E76-9F6E-237C9C5FC57F.jpeg I’ve been using the “gain” video as a guideline for tuning the circuit....

Came across these photos of Jim Weider’s Bassman ODS. Component choices makes sense. But lead dress doesn’t look correct at all. What say you? The only close up shot (no clean TS) 2542BA27-AB4E-45C4-AD78-966434240E5B.jpeg Pot layout in Bassman chassis. 4DFA75BA-F210-469C-99CF-81E8574C2EBA.jpeg

dorrisant wrote: ↑Mon Aug 15, 2022 4:10 pm What schematic and layout are you using?

Mostly working out of this thread, and some educated guesses:

http://ampgarage.com/forum/viewtopic.ph ... e&start=30

Taking my time building an UP amp into an old Bassman 50 amp chassis. That rock/jazz switch is a PITA to wire. Still dressing wire.

Let me know if you guys see anything.

Thanks!

Martin,

Thanks for the confirmation!

Hey all, I’m looking at this 50 W once owned by Michael Landau. Can you guys help me identify the cathode value of the first stage? I’m reading it as 2.74K. Red-violet-yellow-brown-brown-red. Though the violet band is hard to see on the blue casing. Even at that, the Rp-Rk ratio is 1/18.5, 100K/5K4!...

Hey all,

Planning on building a 4x10 bluesbreaker combo for my rebuilt chassis. Anyone own a 1961 and can take measurements? Or have built a replica combo cab?

They’re the square cabs in the middle of the picture below.

Thanks kindly!

sluckey wrote: ↑Thu Aug 20, 2020 2:53 am Looks similar to an old Sunn. I'd really like to see a schematic if/when you get one.

Working on a schematic for this one. From the 470k mix resistors on it’s exactly the driver section of a Dynaco Mark III/Sunn 100S amps! 6AN8A driver tube and all.

It’s a Mosrite amp built in the 60’s by Alexander Dumble. No schematic yet. Dynaco A431 OT, EL34’s, verbatim Dynaco power amp, Fender preamps and tremolo. Just studying the photos to understand what’s going on. Cleans were supposed to be HUGE, amazing sounding. 2C3C513A-9B08-4034-967D-5E360717D4B4.j...

PT is a Thordarson 22R07. HV winding is 350-0-350 @ 200mA. Help me understand this bias supply circuit. Looking at the picture below, one side of the HV goes to the .05 cap, 27k to ground, and diode. Voltage divider and negative DC. Burned(?) 15k to ground is supposed to be the RC low pass network, ...

Aaron,

Do you have any other photos of the Bandmaster? Front or side? Would love to make a project of it!

Aloha Phil, I guess I didn't recognize the layout of the PI in the amp. More reading to do. I appreciate it. I'd think reading up on the valve wizard's site on the different kinds of PI's is a good way to make some sense of it. I bought his books and love them. http://valvewizard.co.uk/ Go to the se...

Phil, Thanks for the heads up on adding GNFB. It wasn't quite on my radar as fine tuning goes, but I can absolutely see how this amp would benefit from GNFB. Iʻve been brushing up on it, but Iʻm not nearly familiar with the cathodyne PI as I am with long tail. Would I just set up a feedback network ...

Hey all, I’ve just come into a 2061x that breaks up too early, even with a replaced OT. (I received it with a replaced Classictone 18 watt OT.) Hereʻs a quick list of all of the changes Iʻve made thus far: 1. Changed the Rp/Rk of V1 to 220k/1K5 (shared cathode), 2. Retuned the Bass channel cap value...

22AWG solid core PTFE that comes in all kinds of colors. https://www.ebay.com/itm/100-Ft-20-Awg-Solid-Core-silver-Plated-600V-Teflon-Wire-Audio-Tube-Amplifier/173399132657?epid=2255997434&hash=item285f64c9f1:g:A04AAOSwM4xXYIDP does anyone know what this yellow wire is he uses in all the "mod" amps? ...