JANAD!

Hey @Amp Mad Scientist take a look at these schematics and tell me what the preamp tubes are doing. I see that V4 is the phase inverter. Looks to me like V1a is gain stage 1 for both channels, V1b is gain stage 2 for the ultra channel only. Are V2a, V2b and V3a all gain stages as well? It appears that V3b is for the tone stack.
 

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Bocc69 said:
Real Nice amp, congrats.

You get rite in there, good for you....Ihave a DSL40c, took me a year to roll tubes.
Where do you purchase most of your tubes?
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I usually get current production stuff from Tube Depot. For vintage I tend to get from one guy in Pennsylvania that sells on Ebay. His prices are good and the tubes have all been excellent. I don't let myself spend over $30 with shipping on a vintage preamp tube. I have been using all current power tubes so far. I'm hesitant to spend the big bucks necessary for these. I would like to get a vintage pair for my 1987 since it relies on the power tubes for its tone. I've had about 10 different preamp tubes in the DSL already and plan on rolling a few more today.
 
I just replaced the stock Marshall branded JJ power tubes with a set of Electro Harmonix EL34s I had laying around. I didn't pull the amp apart to check plate voltages, but the factory reading at the test points was 79ish mv, so I redialed to 80ish mv after replacement. I am really liking the sound of this amp. I put a Mullard CV4004 in V1 last night and took out the 5751 from V2 and put in a GE 12AX7. I am finding both of the ultra gain channels great and neither gets muddy, fizzy or over driven with this combination.
 
Mitch Pearrow SJMP said:
Congrats on the new amp Chris.
They are great tone monsters, I still love my Dsl40c’s.
Cheers
Mitch
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Thanks Mitch. I'm really enjoying it so far. I've been rolling tubes all day. For some reason I like it best with a new Mullard CV4004 in V1 and vintage GE 12AX7s in V2-V4. Did you end up with any lower gain preamp tubes in your 40s?
 
Cadorman said:
Thanks Mitch. I'm really enjoying it so far. I've been rolling tubes all day. For some reason I like it best with a new Mullard CV4004 in V1 and vintage GE 12AX7s in V2-V4. Did you end up with any lower gain preamp tubes in your 40s?
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Yes I most certainly did in both of them, from the care package that you had sent to me, been doing a lot of playing on the red ultra 2 channel since.
One is a bit darker than the other, think I need to find another Ruby ,or sovteck for V1 on it to make them both sound the same.
 
Just went back to a JAN GE 5751 in V2. It's just better sounding and I can use all of the ultra channel 2 gain without it getting muddy.

Final standing for the day is:
V1 Mullard CV4004/12AX7 new production
V2 JAN GE 5751 vintage
V3 GE 12AX7 vintage
V4 GE 12AX7 vintage
Power: Electro Harmonix EL34 EH
 
Cadorman said:
I usually get current production stuff from Tube Depot. For vintage I tend to get from one guy in Pennsylvania that sells on Ebay. His prices are good and the tubes have all been excellent. I don't let myself spend over $30 with shipping on a vintage preamp tube. I have been using all current power tubes so far. I'm hesitant to spend the big bucks necessary for these. I would like to get a vintage pair for my 1987 since it relies on the power tubes for its tone. I've had about 10 different preamp tubes in the DSL already and plan on rolling a few more today.
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Thanks. I have a dsl40c that I need some tubes for.... I'm also not looking to break the bank searching for a tone that I won't ever find. I'll check out tube depot for sure.
 
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