Ampeg Rocket info, please...

My son has stumbled upon an older Ampeg Rocket, bought new for his friend's mother back in the day. He says it sounds wonderful, would be great in a jazz/big band like he played in during high school...

Apparently the tube line up is 5y3, a pair of 7591's or 6V6's according to the paper inside, some indeterminant pre-amp and a 6SL7 pre-amp...

To me it looks pretty rough, but the lady wishes to sell it for $ 350 or so. Is this reasonable to look at, or should we run very quickly away...???

Bill Ashton said:

My son has stumbled upon an older Ampeg Rocket, bought new for his friend's mother back in the day. He says it sounds wonderful, would be great in a jazz/big band like he played in during high school... Apparently the tube line up is 5y3, a pair of 7591's or 6V6's according to the paper inside, some indeterminant pre-amp and a 6SL7 pre-amp...
To me it looks pretty rough, but the lady wishes to sell it for $ 350 or so. Is this reasonable to look at, or should we run very quickly away...???

Click to expand...

Hi Bill; in a lot of Ampepgs, the printed schematic says 6V6s but it's commonly scratched out to say 7591s. Whichever way it is, you can just about bet that if there's a hand-written note, that's what's in the amp. The 12a model should have two 6SL7s ... if the amp is in good condition, $350 is about the going rate, especially if in fair to good condition. As ever, if the power supply filter caps are original, there's a major bump in performance with getting them refreshed and another bump if the speaker is original and replaced. Good luck.

Thanks!

Are 6V6's interchangable with the 7591's or is it one or the other? Which would be the better choice, tone wise, assuming the proper biasing and good caps?

Bill, the pinout is different for 6v6's and 7591's, They're not interchangeable. 6v6's break up earlier that 7591's.
I like them both!

Bill Ashton said:

Are 6V6's interchangable with the 7591's or is it one or the other? Which would be the better choice, tone wise, assuming the proper biasing and good caps?

Click to expand...

Hi Bill: without rewiring the tube sockets, the tubes are not interchangeable - note mis-match in pin numbering below. Older, tweed-style low-power beginner amps were mostly 6V6 amps and, to my ear, the signature 6V6 tone is associated with those amp; darkish, meatier, lots of compression, rounded, smokey tone. Most twin 6V6 amps are limited to 15 watts. In the mid-60s, 7591 amps became popular because in pairs at 25-30 watts, they put out more power/volume. 7591s are more like 6L6s than 6V6s: cleaner at lower volumes and breaking up much later.

Thanks, just the info I needed!