Smoothing caps?

[sepulchre]

I saw this in a D'Lite schematic in the overdrive section:

[img:484:233]http://i269.photobucket.com/albums/jj55 ... rdrive.jpg[/img]

Schematics of Dumbles I've seen have caps in the same places but are 350pF. Are these for smoothing? Or do they have some other purpose?

[Structo]

Commonly known as snubbers.
They do indeed smooth the top end.

[sepulchre]

Great! I thought that might the case. It's the only real difference I can find in Dumbles and various clones compared to other amps. I built a single ended amp and have been trying to get a smoother sound. I tried 270pF and they seemed to smooth it a little, so I put 500pf caps in it. Sounds great. I compared it to an older amp of the same design and it does indeed sound a bit smoother, but I was wondering if it was just "voodoo", you know.

Thanks, Tom!

[dogears]

Never seen 350. I have seen 250pf and 330pf in many. RF has 250pf.

I saw this in a D'Lite schematic in the overdrive section:

[img:484:233]http://i269.photobucket.com/albums/jj55 ... rdrive.jpg[/img]

Schematics of Dumbles I've seen have caps in the same places but are 350pF. Are these for smoothing? Or do they have some other purpose?

[sepulchre]

[img792]http://i269.photobucket.com/albums/jj55 ... Hybrid.jpg[/img]

I also saw a Dumble schematic from the '70s with 500pF snubbers.

[dogears]

Most of these schematics have mistakes as well as artistic liberties of the drawer.

Don't trust them as gospel.

[sepulchre]

I don't, but 500pF does work very nicely.

[Bob-I]

I don't, but 500pF does work very nicely.

I found that 500pF killed that nice "chirp" on the notes attack. 270 to 330 seems to be the range that I like.

[sepulchre]

For whatever reason, the particular parts, brands, etc. I used building my amp, it has a Lot of high end. If I want more 'chirp' I can crank the treble on the amp, or turn up the tone on my guitar. I run the amp's treble at just under half and the guitar's at just over half. So there's still plenty to be had. If it were another amp I would probably go with 270 or so.

[Bob-I]

You might search on the word "snubber".

[marcos]

For whatever reason, the particular parts, brands, etc. I used building my amp, it has a Lot of high end. If I want more 'chirp' I can crank the treble on the amp, or turn up the tone on my guitar. I run the amp's treble at just under half and the guitar's at just over half. So there's still plenty to be had. If it were another amp I would probably go with 270 or so.

FWIW I tried a nice Two-Rock that had 470 pF snubbers on both OD stages.
Although I tend to agree that this is too big in many amps, in this case it sounded really good (low-plate skyliner, a schematic of this particular amp
was posted by Novosibir a long time ago).So if it sounds good to you,go for it
Trust your ears, Marcos

[jaysg]

Iirc, the snubbers are common to high plate non-hrms, though they're really just one of the tools in the box.

[JD0x0]

mismatched snubbers are the key to smooth tone without losing chirp IMO. Im running 830pf on the second triode and nothing on the first. Sweet open goodness with plenty of warmth without getting too dark and honky. I use teles BTW so a LP player might want a lower value closer to 500pf

[sepulchre]

I've got 500 pF on both. Maybe I should try some alteration, like 270 on the first and 680 on the second. That's what I've got on hand.
Thanks for the tip!