my luthier has suggested he re-tube my V4-b, setting it up with 6550 tubes instead of the 7027's which it has currently. any input out there, anyone ever done this?
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Ampeg V4 - 6550's vs. 7027's
- Thread starter Ripper75
- Start date
I took my V-4 to a tech not long ago wanting him to change it to 6550s, and he convinced me to stick with the 7027s. YMMV
I'm not a tech, but have owned and loved many tube amps. I don't think there's any real advantage to using 6550s because the transformer won't allow higher output. When it's time to do mine, I'll use the 7027s as that's what it was engineered for.
The 7027s in it are at least 20 years old, and it's still loud as hell.
The 7027s in it are at least 20 years old, and it's still loud as hell.
It is a common mod but I am with nysbob, I dont prefer it. I have had two different V-4Bs one with 6550 and one with what looks to be original 7027 that I still have. I didnt have them at the same time so no side by side. My impressions were that the amp didnt really gain any real volume advantage with the 6550s. Maybe a little but its hard to say. It did get hotter. Could probably cook eggs on the rear chassis. Cranked into overdrive, the V-4B with 6550s sounded a little fuller while the 7027 one has an edge to it that I love. Its a little punchier sounding I guess. I like the 7027s better.
And remember, it is a mod, not a re-tube. 6550's will not work without minor modification to the bias circuit and the tube retainers.
when i got my v4 it had 6550s and i had the mods done to keep it that way. i love the sound of my head with the 6550s, but i couldn't tell you how much better it would be with the 7027's because i didn't take the time to a/b them.
Right, the whole reason people started modding them for 6550's in the first place was that for a while, 7027's were not being made. That left 6L6, EL34, or 6550 for the most part, any of which will work in the V4, as long as it is biased correctly. Now that 7027's are readily available again, why not use them? Some people say that it sounds ballsier with 6550's, but last time I checked, that was what an EQ was for.
- Jul 11, 2006
- 433
- 12
- Disclosures
- Tech Director, dBm Pro Audio Services, New York
As was stated, the reason for the mod was the unavailability of 7027's. 7027's are readily-available now, but I suspect that they are, in fact, repinned 6L6's. This practice of "reissuing" vintage tubes is not uncommon. All of the 7591A's I've seen (another popular Ampeg tube) both appear and sound like rebottled 6L6's.
For the record, there is barely a discernable difference between an Ampeg running on 7027's or 6550's. The 7027's have a higher plate resistance, but it doesn't mean much sonically.
Early SVT's used 6146B power tubes with anode caps. The 6550 is closest in power ratings and toughness. You COULD use 7027's, but 6550's, with their lower plate resistance and paralleled 3-per-side makes for a nice bass monster power amp.
For the record, there is barely a discernable difference between an Ampeg running on 7027's or 6550's. The 7027's have a higher plate resistance, but it doesn't mean much sonically.
Early SVT's used 6146B power tubes with anode caps. The 6550 is closest in power ratings and toughness. You COULD use 7027's, but 6550's, with their lower plate resistance and paralleled 3-per-side makes for a nice bass monster power amp.
