I'm back, thinking about 6550s in a bassman chassis, opinions?

[mlove3]

first check back at ampage after being gone for years, wow!
I discovered ampage while I was in school in the 90s (so long ago!). Still gigging with my homebrew modded SF bassman, and hey, it still works!

So I have a hacked mod platform SF bassman chassis AB165, thinking about installing 6550s in place of 6L6s for more headroom and bass, anyone ever try it?

thanks in advance

[loudthud]

If you measure headroom by how far you have to turn up the volume control, you'll have more. If you measure headroom by how loud the amp will get, you'll have less. 6550s really need a different transformer set before they smoke 6L6s. At that point you might as well build a whole new amp.

[Don Moose]

To echo Mr. Thud -

6550s like much higher voltages (600V plates, 300V screens) and at those voltages can produce a lot more power (headroom), but need a more capable OT.

They also want 1.6A each in heater current, compared with 0.9A per 6L6, and that's regardless of the voltage rails.

[mlove3]

after reading these responses and an archive thread sounds like it's not worth it.

I always liked the sound of my 80s marshall with 6550s, big and loud and clean bottom end. I ain't luggin one of those beasts around anymore though.

[loudthud]

A Sunn 200S is only a couple of pounds more than a Bassman. And the transformer set is available.