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Preamp tubes

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6/15/2000 7:31 PM

Preamp tubes

Ryan,

I lied.

I DO have the 12AX7LPS in V1, and it sounds GREAT. No microphonics at all that I have noticed. Of course it's only been in there for a couple of weeks, so we'll see how long it lasts. But like I said, these are from the first batch that Sovtek sent out (I think) so they should be pretty high quality.

I've got another 12AX7LPS in the phase inverter position V5, and I've got Tesla ECC83's in V2 and V3. V4 is the FX send/return, and that's still a Mesa branded tube since I don't use the FX loop at this point. May change it if I decide to use the FX loop, may leave it where it is.

Regards,

-Tom

6/15/2000 1:26 AM

Don't choose... build both. It's easy?

I've been pooring over the schematics for the Dual Rectifier all day. If you ignore the clean version of the orange channel there is very little difference between the orange and red channels.

I think that with one triple pole triple throw switch you could have a single channel amp that could be switched from red to orange. The only differences I can see between normal orange and normal red are

1)the capacitor at the top of the tone stack (this could switch between 680 and 600 pf)

2)the red presence knob (this could switch from the red presence pot to a 10K resistor) and

3) and LDR 19 (feedback) (this could switch between open or closed.)

However, you would need to keep both the orange and red channel presence pots to keep things this simple. You could get a stacked double 25K pot so that there is only one presence knob for the user.

By making the amp one channel and ignoring the clean orange mode the complex switching disappears. The more I think about this the more I might end up doing it. Instead of choosing red or orange I think it is better to build both channels when a TPTT switch and a stacked pot are the only differences.

I am a fairly new to this whole amp business as you may know but I think I understand this one alright. If someone checks out my idea I'd like to know if I'm right or wrong.

Peter

PS Where is the "B" side of "V1"? it looks like it is doing nothing to me.

6/15/2000 3:21 AM
Ryan	The "B" side of V1 isn't missing, it's unused. They could have used this tube section for a nice clean channel, but then they would have ripped Soldano off 110%. -Ryan

6/15/2000 3:44 AM
Mitch	Guys, Why not just build the Soldano SLO. I did and its a nice amp. I just wonder how it compares to a Bogner XTC? I hear good reviews about the bogner amps but only heard one in a music store for a minute and it sounded great. The Soldano schem is on the blue guitar site. Just food for thought. Cheers

6/15/2000 5:40 AM

Mitch:

The Soldano schem is on the blue guitar site.

Thanks! I'll have to check that out...

Actually what I was thinking of doing first was just cut'n'paste the 6 pages of DR schematics to make a simplified drawing of the Orange and Red channels (with a few mode switches instead of the umpteen LDR's). To be honest I did not see all of the similarities to the SLO (but they might become more obvious when I simplify all of that LDR switching!) I liked Peter's idea of incorporating a few mode switches so that you could have one amp that would do both channels...

Steve Ahola

P.S. After looking at the M/B catalog I guess that the Red channel has the modern distortion sounds (no NFBL) while the Orange channel has more traditional distortion sounds... Thanks for all of your input on this!

6/15/2000 7:44 PM

I already did the cut and paste thing to make the one channel amp schematic.

http://members.home.com/porkproducts/simple%20dualrec1.gif

http://members.home.com/porkproducts/simple%20dualrec2.gif

The only thing I am curious about is did I remove the orange tone stack correctly. There is a 1M resistor connecting the red and orange tone stack. I just removed it because it is probably close to an open circuit anyway. What is the 1M resistor for anyway?

Peter

6/15/2000 7:54 PM
Peter Michaux	Oops, there was a small mistake. Should be fine now. If someone wants to double check all the changes I made that would be cool. Peter

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