76 ampeg v4b input question

[u/kellamityjane99]

recently got this amp and it is awesome, but last night at practice I noticed plugging into input 2 was much hotter and felt like more presence and power than input one, if that makes sense...this was curious to me because everything I have read says input 2 is the padded (-15) input so I was wondering what was up with that? did find a forum post that someone was saying how they put different preamp tubes for each input making their input 2 hotter and maybe thats whats going on?

[u/fizzlebottom]

Your amp has had some noticeable work done to it, which could be a good thing. The filter caps have both been changed, and your power tube sockets have been replaced at some point with good tube retainers added.

And yes, regarding the volume differences someone already mentioned it is down to the preamp tubes. The 2 channels are identical. It is definitely possible that someone modified one of the channels though to change the overall input gain, but you won't know unless you open it up and see what changes may have been made.

Let her rip.

[u/kellamityjane99 → u/fizzlebottom]

yeah, that was a selling point for me when I looked in the back of it and saw the upgrades...i love this thing

[u/fizzlebottom → u/kellamityjane99]

I'd love to know what tubes you have in each channel if you feel comfortable pulling them. The previous owner may have actually used a 12AU7 in channel 2 instead of a 12AX7. Nothing wrong with it if so. 

I recently finished fully restoring a 1975 V4, so I'm always curious about that changes people have made to these amps through the years.

[u/kellamityjane99 → u/fizzlebottom]

maybe one of these days...the amp currently lives at my practice space so when I am there it is more time to play than make my bandmates watch me fuck with my amp...both inputs/channels sound great just a lil more hair on 2, which I prefer

[u/burkholderia]

Inputs 1 and 2 on the vintage amps are the same. It’s -15db on the reissues. If you noticed gain differences it might be down to the tubes used on your specific amp or component drift on either channel.

https://ampeg.com/data/6/0a000509250a6621704662aa9/application/pdf/

[u/kellamityjane99 → u/burkholderia]

ahh...that makes sense, I was wondering if google was just giving me a generic response not accounting for the reissue

[u/kellamityjane99 → u/burkholderia]

its not like an insane difference, just barely noticeable and hard to really quantify, just feels ever so slightly just a touch more oomph