• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Scott 299D, which 12AX7 does what?

Jenkster

Jenkster

When I had talent
Subscriber
I have a NOS Valves restored 299D. I'm just curious as to the function(s) of each 12AX7 by position? I have looked and, short of having someone decipher the schematic, can't seem to find that information. Any help would be greatly appreciated. I just put in a NOS quad of GE 12AX7A/7025's and a NOS pair of Sylvania 7687's and she is sounding great. Thanks!
 
Register to hide this ad
V1 and V101 are left and right phono respectively.

V2 and V102 are tone and gain (again L, then R).

V3 and V103 are gain, only (?)

V4 and V5 are left output (7591a for mine)

V104 and v105 are right output.
 
Last edited:
Thank you, I appreciate it. Looking at the tubes from the front/faceplate, is V1 on the left or right? The serial number is 127430 which I assume is an early one?
 
Yes, you have an early series. The info I gave above is for an early series model D, as luck would have it.

V1 is the left channel. Is it on the left side as you face the front panel? It should be (?)

Try to read the silk screening on the chassis. Each tube is labeled, although it can be difficult to read. Shine a light beam across the surface, you might be able to read them. I can barely read mine, even though I know what I'm looking for.

I bet you can still read the printing. Craig wouldn't have wiped it off when he cleaned it; it may have been gone prior to restoration. It's not a big deal if it's gone.
 
Last edited:
Thanks again, I appreciate the info.:thmbsp: I will take a look at the chassis tomorrow. It's a little hot right now. :yes: :music:
 
You must log in or register to reply here.
Back
Top Bottom