So it’s time to replace the old tubes that came with my white top ZP3.  I noticed that I’m getting a channel imbalance with lower volume coming out of the right channel as well as an echoing sound.  Since I don’t know the condition of the tubes that the amp came with, I decided to put in a new Stock Decware 5U4G rectifier, a NOS Westinghouse OA3, 2 used Tungsol 12AX7’s, and a used 12AU7.   I’m still getting the channel imbalance, so now I’ve decided to buy 3 new tubes for the first 3 positions.

For the 12AU7… I just ordered a GE12AU7 from Upscale audio (Kevin’s Stash) that I’m very familiar with.  I ran this tube in my old ZSTAGE, and it was dead silent with no microphonics and great detail.   

So now we come to the 12AX7.  I’m leaning toward the GE JG triple mica black plates.  I know with the first position, it’s important to have tightly matched triode sections.

So my question is….if both triode sections are not perfectly matched…how far off can they be before it causes an issue.  This is my first go round with this tube and running th ZP3, so any advice and insight would be greatly appreciated.

Thanks
Dom

Lon,

The rectifier is brand new, and the VR tube is the one you gave me.  I don’t know the history of the two 12AX7’s, and the 5814 is also the tube you gave me.  

Yes…I do suspect it could be the ZP3 itself…but before I send it in…I figured it’s worth a shot to just replace the tubes first.  

We both know…if I send the unit in…I’ll be hell bent on doing all the upgrades….which is what I really didn’t want to do right now.  Sort of a conundrum.  

Dom

Thanks.  I’m going to check it out further tonight after work. I already checked the speaker connections, and when I switch to digital everything sounds fine.  The cabling for the ZP3 was the same cables I was using when I ran the Rega Fono.  I didn’t sell the Rega unit yet, so I’m going to plug it back in just to try to isolate the problem.  If the new tubes aren’t the cause, then it looks like I’m going to have to place a call into Steve.  I guess I may as well call Sarah get a quote on the full upgrades and the Anniversay mods.   Depending on the cost…maybe I’ll just do the Anniversay Mods and keep the stock caps.

While I know it’s nice to have all of your components with the same brand of caps for the internals….maybe running vinyl and a bit of variety keeping the stock caps is a good thing.  Any thoughts?

Dom

Yeah It’s probably an in internal issue.  With my unit sitting for a good amount of time before I bought it, maybe running it regularly like I have been caused the issue.  I’m just guesstimating at this point though.  I sometimes wonder if by not having all the internals the same will compromise some synergy since these amps are so revealing.  

I have a 1PM call tomorrow with Steve, and Veronica is going to send me over a breakdown of all the upgrades and warranty transfer.  I’ll keep you posted.

Sounds like a good plan.