Joe, the B25 is the most amazing amp I've ever
owned. It can do more at mid-volume than my SVT is capable of anywhere in its audio spectrum. By playing around with
the tone controls and ultra hi/lo I can go from a loud, clean tone to that low growling rasp that is normally only associated
with Rickenbacker bass guitars (had one, didn't like the way
it played).
I
told you I was an amp nut and that's true. Two years ago I bought an Acoustic Image Coda, it's probably the best of the new
switching amps, tiny, feather-light and loud. It's the amp I've been using for live performing run through a 4 ohm 2X10 Bag
End cab. One of the advantages of this amp is that you can make it sound just about any way you want it to. Since playing
through the B25 I've decided to sell it to an upright player here in town. The SVT is going too, I don't need either of them
now, the B25 is just that good, and I couldn't be happier. I've played through just about any kind of amp you can name through the years and this one perfectly
represents what a bass amp should sound like to me. It has many sounds and they're all good. It's also the loudest 65 watt
amp I know of. I can't imagine a situation where it could needmorevolume. Any outdoor shows we do would see it miked and running
through the mains, sounding sweet.
Again,
I can't thank you enough,
Chris
I have restored a number of Ampegs: Jets, Gemini II, Reverberocket, B25s and this B25.
I do not consider myself an authority on Ampegs, but I have had pretty good luck with them.
This B-25 was fitted with a new power transformer from Fliptop.com, 'all things Ampeg,' and it is an identical drop-in replacement
for the original unit. I converted the amp to an adjustable bias and set it up with 6550 power tubes. This required
a small filament heater transformer dedicated to the 6550 tubes, as they draw about twice the heater current as the original
7027A power tubes (same family as 6L6 and EL34s).
I added a 500mA fuse in the high
voltage (530 volts DC!) B+ power supply line. Also changed up the grounding scheme to my personal taste for noise reduction.
Sense the main board in the amp had suffered considerable heat damage over the decades, I replaced virtually every part
on the board -- upgraded all resistors to at least one watt and went with orange drop caps.
That's about
all I know for now. The work was worth the results.
This is a circa 1969 Ampeg B25 Head.
It was a real mess when it arrived here, but Chris Buttitta can tell you that after a complete restoration by ETAC, this
amp ..... well, let's let Chris tell you: 
