I think this has been posted before but can someone tell me the pre-amp tube functions on a DRRI, going left to right?? (first one's a 12AT, then two 12AX's, then another 12AT and then another 2 12AX's). Is it just one 12AT and two 12AX's for the normal channel and the same for the vibrato channel? (one phase inverter 12AT per channel?). I had to swap out a bad tube last night and I'm not sure of the function for each tube location....
Thanks for the information.
Right to left, from the back panel:
V1---normal channel preamp
V2---vibrato channel preamp
V3---mixer stage
V4---reverb
V5---trem
V6---phase inverter
Almost. V3 is the reverb driver tube. V4 is the reverb recovery/mixer tube.
Several guitars in different colors
Things to make them fuzzy
Things to make them louder
orange picks
AS you view the amp from the rear, the first 12ax7 is the first gain stage and the second gain stage of the normal channel. That tube amplifies the signal from the input jack,and sends it thru the tone controls.
The next tube handles the vibrato channel the same way.
These are the two tubes that will have the most effect on the tone of the amp, as changing the tone of a signal when its very small ,like out of the guitar or after the first gain stage( hence the tone controls right after the first gain stage) has a big impact the in a large way gets carryed thru the rest of the amp.
The last small tube (12at7) next to the big output tubes can be changed out for a 12ax7 which will drive the output stage into clipping sooner while having the preamp closed off more.
A bit more info fer U here
http://www.kcanostubes.com/content/n...sp?ArticleID=5
Awesome, thanks!
Looks like V2 and V4 are the most important to tone if you just use the vibrato/bright channel....I did notice a nice difference when I put a new JJ in each of those spots. I'd like to try 5751's in those spots sometime.
4 out of 5 cape-wearing swinging horses prefer a 12DW7 in the V4 position.
Several guitars in different colors
Things to make them fuzzy
Things to make them louder
orange picks
You're holding back, Kap'n...I had not seen this.
Assuming I could play the same game with an original AB763?
Sure. The 12DW7 is 1/2 of a 12AX7, and the other half is something with a lower amplification factor.....12AY7? In any case, the half with the lower gain just happens to be the side that is the reverb recovery stage, giving you much more usable range from the reverb knob.Originally Posted by Cygnus X1
Several guitars in different colors
Things to make them fuzzy
Things to make them louder
orange picks
OK, I've been using a 12AY7 in the send anyhow.
So it changes the range, just on the opposite side. What was 3 is now closer to 5. I like less reverb (also I think less hiss), not more.
Do you have a dwell control on yours? I've put a voltage divider on one of my amps to smooth out the drive.
Several guitars in different colors
Things to make them fuzzy
Things to make them louder
orange picks
No...it's a drip edge (blackface inside) 67 DR.
I've played with the tubes in the reverb section to cut the intensity of it a bit. It was just too sensitive...that 3 setting sounded ok, but it was too touchy. So I cut the drive on it by swapping the drive tube to a lower gain 12AY7.
A side effect happened to be less hiss for the same slight reverb.
I have that KCANOS Tubes Page ( Link above ) Printed and on my work bench. Great info and I forget stuff so....
Also, heres a good link on differant pre-amp tubes and what they do
http://thetubestore.com/gainfactor.html
Great site and a good place to buy stuff. There is also a bunch of other great info and helpful reviews if you search around on there site.
Peace Out !
Posting Permissions
Reply With Quote