Dumble ODS Clean Channel question (too clean?)

[ericlc]

Hi,

I build an non-HRM 2x 6V6 ODS clone.
It's based on #183

The clean channel is really clean, which means that it stays clean with the volume on 10 where I was expecting that the preamp would distort at least a bit

I what wondering what your experiences are with the clean channel?

Thanks in advance

Best,
Eric

[jelle]

What kind of guitar do you use, pickups? And what do you consider clean?

[ericlc]

I use a Stratocaster and a Les Paul
So both single coils and humbuckers

What is my definition of clean.
Well no distortion or crunch whatsoever
Let's say hifi audio

[jelle]

With a les paul you should get breakup. Something is up.

[ericlc]

That's what I thought.
Do you have any ideas where too look?
Plate voltages, NFB, GNFB, one-tube reverb mixing resistor?

[splgeo]

What are your voltages? I know my bluesmaster will break at around 7-8 on the pre volume when struck hard

[ericlc]

My voltages are:

V1 191V/197V
V2 195V/198V
V3 299V/203V (1-tube reverb)
V4 293V/288V (PI, needs to be readjusted)
+B1 446V (OT)
+B2 +445V (screens)

[ericlc]

I noticed in some D'Lite schematics the GNFB resistor is increased from 4K7 to 6K2, so effectively less GNFB. Since I have 2x 6V6s rather than 6L6s I can image that adjusting the GNFB resistor is necessary.

[ic-racer]

Does the clean channel break up with the PAB engaged? Have you have checked for weirdo stuff like a "250K" pot that is really 150K or other things like a cathode bypass cap that is non-functional etc.

[splgeo]

is you think is could be gnfb you could temperaloy use a trimmer to adjust to taste, and see if that is your problem

[DonMoose]

It's kinda cool though - you accidentally built an SSS or Tone King Consoul.

[talbany]

What kind of 6V's are you using??... JJ's

Tony

[ampgeek]

What are you seeing for voltages on the pre-amp cathodes?

You can calculate the current flow through the triodes (ohms law across the cathode resistor) and compare those to standard values.

The gain at the plate load resistors is directly proportional to the current at the cathode so this might provide some insight into a potentially sluggish gain stage.

Good luck,
Dave O.

[ericlc]

@Talbany
Yes, I use JJ 6V6S

@DonMoose
Yes, maybe I should keep the amp as is

@Others
Thanks for you suggestions.
I'll pull the amp out of the cabinet this weekend

[talbany]

The JJ's are not really considered a "true" 6V6.
They are more like a smaller more compact version of a 6L6,especially if you run them up around 450V can have quite a bit mo headroom than the classic versions (we compare them too)run between 350/400v..To me they are a very different animal..

If your going for classic 6V tone,feel,breakup, spec your PT at or around 350V and pick up a set of Sylvania's or Black plate RCA's... sit back and enjoy what a "true"6v sounds like!!

Tony