D180 Preamp Tubes.

Greetings, all.

I just picked up an old D180 (no-graphic eq version) and was wondering if anyone could speak to this - I've seen other D180s where DYMO labels were used by Boogie to note where the 12AT7 goes, as opposed to the 12AX7s. This amp doesn't have any labeling inside. Any thoughts? I seem to remember reading something where if there was no label, all 4 tubes should be 12AX7s, but I'm not sure.

Also, it seems like the feature where the Master Volume knob changes the voltage to get fuzzbass at low volumes doesn't work. Could this be from improper tube placement or a wrong tube in the group (it came with 3 Ruby 12AX7s & 1 SPAX7)? Thanks all for your assistance.

I found the reference I mentioned - it was in the Talkbass forum. Can anyone here confirm or deny?

joetiii
01-04-2006, 08:45 PM
Spoke with George from Mesa Boogie today. He cleared things up for me on the D180 preamp configuration. Apparently there are three versions... one had 2 12AX7's in the preamp, a 12AT7 phase inverter and one more 12AX7 in the final master stage. A second version had one 12AX7, 2 x 12AT7's and a final 12AX7. The last version had 4 12AX7's. The amps were only labeled if/when they had different tube sockets.

i wonder if it was any internal differences in the 3 versions. can anyone confirm the schematic for the d-180 thats availible at schematic heaven? i have not seen one in person or pics of the guts. i want to build a mesa bass amp but cant decide on the d-180, 400, 400+ or buster. any of you guys have a preference for one of these over the others?

Hi jbrew. No offense, but you're changing the subject, not replying to my questions. You should post your questions in a separate message / topic. Thanks.

--- Victor

sorry about that i just thought if someone had schematics or additional info that it could help both of us.


the info i have says
v1 12ax7
v2 12ax7 unless labeled 12at7
v3 12at7
v4 12ax7

hope this helps