non-HRM 4-6CA7 build,cathode biased

[phsyconoodler]

I just finished a non-HRM build with 4-Philips 6CA7's and I used old Traynor Mark III Iron.The cleans are spectacular and the OD is pretty good;needs a bit of tweaking.
I added a one tube reverb as well.
But the thing I did different is I cathode biased it.It has 430v on the plates(416v plate to cathode)
It has a huge amount of clean headroom,even though it's cathode biased.
The tubes are loafing at 17.5 ma right now and I was wondering what most guys consider a safe bias point for this amp?It sounds great now,but I bet it could be better.I am using a 90ma- 4H choke as well.It definitely sounds better with the choke vs a resistor.
The reverb is quite good,and gets plenty if you crank up the master.The mix point is right at the master.
It sounds quite a bit more complex than a two bottle amp.I'm using a 10" and 12" speaker.A mojotone Greyhound and a Celestion vintage 10.Sweet sounds!

[Structo]

Sounds cool.
I've always biased my cathode amps close to 100% depending on the tubes.
Maybe 90% for safety.

[talbany]

Getting class true Class A out of a pair of 34's running those voltages is pretty tough.. I wouldn't go any higher than 90% personally.. a shared 280 ohm 15w would be about the lowest I would go as that would be somewhere around 80% range.. a 360 ohm would be somewhere in the 65-70% range depending on the tube @430V..or somewhere in between..

Matchless Clubman uses 270 @ 420 on the plates.. Around 90%. Pretty hot..

17.5 is real cold!!

Tony