102 as Lowplate Classic

[vibratoking]

Vibratoking, yeah that is kind of why I avoided upping the snubbers. I like as much high end to sing through the OD as possible. Do you have a preference for a way to trim a little harshness off the top of the OD? I think Robben Ford just backs off on the volume control on his guitar a little.
CW

I like to leave the high end as well and I don't like to trim the harshness in the amp. I prefer a bright amp. I can make a bright amp darker, but not the other way around. I use the guitar vol and tone as much as possible. I also pay attention to where and how to attack the string. It's not perfect. BTW, I have a lesson DVD of Robben where he was in a phase where his vol and tone pots were bypassed in his guitar. He used a vol pedal only. To each his own.

[Charlie Wilson]

Vibratoking, I agree. My friend who is a really great guitarist came over and played through my amp. He made it sound amazing, same guitar and settings I was using. I have studied and played classical guitar for quite awhile and know that subtle changes in how your fingernail strikes the string influence the tone greatly. Why should the same concepts not be applied to a plectrum hitting an electric guitar string? The funny thing is he thought my amp was kind of dark.
CW

[aflynt]

Whoah! I've never seen the SRV dumble guts before! That's his ODS? Looks like a low plate. Can't tell if it's Syliner or classic stack. 100k slope?

RE: technique - I've recently switched to 1.5mm small teardrop Acetal Clayton picks from .71mm Dunlop Delrins. Much darker overall tone. Better control too I think.

-Aaron

[Charlie Wilson]

Good point Aaron. I kind of made the assumption that it was a classic tone stack with a larger treble cap. The smaller V1B coupler and feedback resistor (looks like 2k7 with a trimmer) are interesting. I am pretty sure it has a 100k slope resistor. Might be a nice way to fill out the high end a bit and cut a bit of lows. I think I read somewhere that Dumble said SRV had a hard time getting a ODS to work for him and then came the Steel String Singer.
CW

[aflynt]

Yeah. Something about 100 megatons of pressure.

Interesting lead dress on V1 and 2 also. looks like just the v1b cathode and plate wires are run together. I've just been running v1b and v2b together lately and kind of think it sounds a bit sweeter than running all 4.

-Aaron

[Charlie Wilson]

Yeah I noticed that about the lead dress also. I don't know how early this amp is. I thought maybe his lead dress had not evolved yet but then again there are plenty of 2nd gen amps that have what we commonly see in Dumble lead dress. Anyway, I like sweeter.
CW

[lovetone]

Hi Charlie thanks for posting the image i've not seen this one before

What make of resistors are those, the type the slope resistor is?

[Charlie Wilson]

Lovetone, I found this picture on an early post. I am expecting someone who knows all about this amp to chime in at some point. All of the yellow carbon film including the slope are Sprague Q-Line(1w). The preamp plate resistors are early Dale RN65D and cathode resistors are Mepco metal film. I think there is more of a story that goes along with this amp but I can't remember what it is.
CW

[lovetone]

Thanks Charlie, I know these resistors make a difference, I don't think these will be easy to find. I did wonder if these might be Draloric as they look similar I'll have to look for the Q-line ones, although I don't hold much hope. Have you used any of the Q-line type your self?

Geoff

[Charlie Wilson]

Geoff,
Those resistors were made by Draloric and packaged by Sprague. As far as finding any, they are very rare, pretty much impossible to find. The funny thing is that back in the day you could buy them at Radio Shack.
CW

[FuzzFaceBuilder]

As best I know, that low plate classic with the .002 treble cap is Jackson Browne's(?) ODS that HAD loaned SRV while building amps for him. Cool!

[Charlie Wilson]

Shoot, I wish I had known that was Jackson Browne's amp a couple days ago. Jackson was at my friend's gig and apparently he enjoys talking about gear. My friend may visit with him again and I will have him ask Jackson about that amp.
CW

[jam-mill]

Looks like a 33K grid resistor into V1a; probably helps with the pick-up loading on those older low-output strat pickups.

[Charlie Wilson]

Jam-mill, Ry Cooder's Borderline which is also a Low Plate Classic also has a 33k grid resistor as well as #124 which may have started out as a Low Plate Classic. Hmmm interesting.
CW

[martin manning]

Jam-Mill asked via PM about the presence cap WRT single coil guitars- 1uF vs. 2uF. I have not experimented with this, and after a brief search I couldn't find much of anything on the forum. Doubling this cap will move the onset of reduced feedback (presence) down one octave and increase gain in the 500Hz-1KHz range. Anyone evaluated this as a single-coil mod?

The input stage grid resistor won't affect pickup loading; that will be dominated by the 1M to ground at the input. The grid stopper's effect is more about the high-end roll-off and RF noise rejection.