The Amp Garage

Yes, it's a pot. The switch doesn't remove it from the circuit, just makes it go to the full 1Meg while preserving the setting. Alternatively, a switch in series with the pot could be used to open the bypass circuit and completely remove it, but it would be a good idea to put a large resistor across...

As far as the lift resistance goes - 22M and 72k seem pretty far apart. What’s the best way to figure out where to start that experimentation? Higher value lifts more of the stack? 22M is the full lift, same as open circuit for all practical purposes. I've seen various values for the partial lift, ...

He collects, shares his purchases and sells probably for a profit. His money and no-one suffers any damages AFAIK. And by the way, where would the amp otherwise go? A collector who puts it in a safe or at least doesn't show it to the world? What would we benefit from that? No harm except driving pr...

I believe he means to bypass it like this. I added the cap to block DC, and the bypass switch to get the full 1 Meg for "normal" mode from any partial-bypass setting. There will still be some effect from the tone controls with this bypass technique.

Did I have the connections correct? That’s where I got crossed-up. So I could follow mdroberts’ schematic and it would work the way most/many prefer? You understood the layout connections correctly. They are also shown in my ODS Eyelet Board .pdf. You can use MDRoberts scheme, but you might prefer ...

Trying to work out the 22M “jumpers” on the mid- boost relay board in the layout. It looks like Com1 to NC1, Com2 to NC2 - but it’s hard to be sure - so I looked at the bm_clone schematic and it looks like NO1 to NC1 (with a 72k?) and NO2 to NC2 with the 22M value. I understand that schematic has m...

I have also made a huge error of not testing the orientation of any of my Orange Drop Caps so I am trying to buy a second hand Oscilliscope from someone on FB Marketplace (Havent gone to pick it up yet) You can do that with a multimeter. See here: https://ampgarage.com/forum/viewtopic.php?p=417375#...

290DX has a slightly lower HV current rating at 230 mA, but the tube compliment you have is the same as the Tweed Bassman that it's designed for. It also has a 5V winding, which you could use for relays if you went to a 5V system. That would eliminate the cost, weight, and complexity of the addition...

Either one would be fine. I don’t think the power stage voltage is all that critical, and you can adjust the first dropping resistor as needed. Maybe make the call based on source, cost, and shipping charges incurred?

Would i still be changing the 820R to a 1.2k or could I just change the 47R to a 33R? Either way will work for you since there is no presence control. If there were, changing the PI tail resistor would change the frequency response of the feedback, which would require a change to the presence cap v...

Yes, yours matches the hand-drawn schematic.

This comes up all the time. You can keep the same feedback resistor on the same tap, and put the speaker on whichever one it matches, or, move the feedback resistor to the tap the speaker is on, and adjust it's value by (New Spkr Tap/Old Spkr Tap)^0.5 Given the secondary hookup for the 1620, you wil...

No problem, and it basically reduces the output 1 dB if the feedback goes direct to the grid. Other than that, I don't know.

GAStan wrote: ↑Mon Apr 22, 2024 6:35 pmWould I have won? :wink:

You have a point there :^) To me, one component being in series with another means they have the same current.

GAStan wrote: ↑Mon Apr 22, 2024 5:59 pmDid I get it correct?

Would you have bet money that you did? ;^)