The Amp Garage

Some other options:
- if you don't want your nephews will ever need to substitute it: 6€ Mouser No:871-B32320I0306K000
- alternative with lower capacitance: 7 € Mouser No:505-DCP4I052507GD4KS
- standard electrolitic alternative: 8 € Mouser No:871-B43541B8476M000

Think so ? Try running your preamp from a regulated bench power supply. Your amp will FEEL different. Yep, I've never done measurements, but doing this exact test years ago I felt the preamp supply derived from the power amp sounded more... "articulate" gives the idea? Like a modulation of the soun...

You can't drive the power supply voltage regulator directly with the envelope follower's output. ...or you can but then the circuit is nothing but a high power buffer and your power supply voltage will be identical to envelope follower output. Not nice. I agree, that's why I talked about scale and ...

The tone will be slightly "browner" as B+ goes down, but you'll hardly notice that. I agree, and that's why I don't think the point is calculating the gain of the amp. Know how to calculate gain from plate curves and a load line ? Know how to calculate change of gain in dB ? This is a very simplici...

imjonwain wrote: ↑Fri Nov 11, 2022 2:15 pm Are we talking about a tube or SS preamp?

Tube. SS has usually really tight PS, especially nowadays with SMPS.

I don’t want to emulate the sag of a power amp.
But… why you would set the gain to the same value of the final stage? And why you say a triode has less gain than a pentode?

Have you seen this link?
https://orangeamps.com/articles/2006-ad ... r-designs/

I think it means they have 8 sections and dual slot. An Hi-Fi-ish design. I remember to have read on other sites they are five sections.

People who bought from Rob often came to sloclone asking for assistance, so I wouldn’t be so sure about a prompt and positive feedback. I hope for you to be wrong.

R U still alive? :mrgreen: To me it seems a nice built considering it’s your first SLO. Please report your impressions and don’t rush on doing mods. SLO is a particular beast and needs time to explore all nuances it is capable of. One of the best sound I’ve got from it is removing the bright switch ...

Hi, I was thinking about how to emulate the sag of a full amp in a rack preamp. - process a buffered outout (with a pot to set the emulated sag effect) through an AD737 ( https://www.analog.com/media/en/technical-documentation/data-sheets/ad737.pdf ) - scale the output to modulate the base (gate in ...

Some more plots:

Old scratchy ones:
- 5k lin pot fully CW with sweep on 100n 220n 330n 470n 680n 1u;
- 5k lin pot with 680n;

Non-scratchy ones:
- 4k7 plus 5k lin pot with 680n;
- 4k7 plus 10k lin pot with 680n;
- 4k7 plus 25k lin pot with 680n;

I report the files here for other users too.

The 25k plus 100n presence pot that is in almost all post-80s amps works only on the very last part of the rotation.
I use 10k instead of 25k because it has a wider useful range (but I still prefer the old scratchy one).

I discussed the argument in another forum.
I hope to be ok to link it here to give some more points of discussion here, otherwise please moderators remove the link: http://www.slocloneforums.com/viewtopic ... 24&t=14225

Not really. You are live, you want to change the guitar so you unplug your guitar but not the amp, then the grid is no more referenced to ground.

The shelving with that configuration has 5dB extension (between bypassed and not), and the -3dB point is around 700 Hz for the 250 nF and 400 Hz for the 470 nF. It is uncommon but not the first time I see these values (I've used them too in higher gain amps), specially with low wattage amps, to avoi...