To add to what I posted above, the attached shows how the PI balances under clean & clipped conditions for 'stock' and various split load resistors. The combination I posted above is one where the balance doesn't vary much between clean & over-driven. The last one might be worth a try if more drive is desired. (Note the input signal is from further back in my amp model, not the PI input.)
Andy
			
			
						New 4-4-0 and Asteroid 60 amp porn
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Re: New 4-4-0 and Asteroid 60 amp porn
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						Re: New 4-4-0 and Asteroid 60 amp porn
Having had a chance to play around with these changes using 12ax7's I must say these changes have produced a much more useable circuit. I am able to vary between clean and driven with no noticeable volume drops and have a bit of chime in my clean tones. It is much more subtle than a full on Express but it is there none the less. I've still yet to make the pot changes but I see no reason to not make that change as well. Thanks to Tillydog for the spice simulations.
			
			
									
									"It Happens"
Forrest Gump
						Forrest Gump
Re: New 4-4-0 and Asteroid 60 amp porn
No worries 
Did you pick up that the grid leaks (and grid stoppers) on the 6SN7 had gone up to 220k, too?
You could try the values at the right of the table, too..... (hint)
Andy
			
			
									
									
						Did you pick up that the grid leaks (and grid stoppers) on the 6SN7 had gone up to 220k, too?
You could try the values at the right of the table, too..... (hint)
Andy
Re: New 4-4-0 and Asteroid 60 amp porn
Yes, those I caught. Initially the tube on your schematic was unlabled and I assumed had not changed. I am playing a Les Paul with burstbuckers and have plenty of "hair". I might just leave it as is until my plate clears up enough to experiment.Tillydog wrote:No worries
Did you pick up that the grid leaks (and grid stoppers) on the 6SN7 had gone up to 220k, too?
You could try the values at the right of the table, too..... (hint)
Andy
"It Happens"
Forrest Gump
						Forrest Gump
Re: New 4-4-0 and Asteroid 60 amp porn
A fair assumption! My fault for not making it clear until after the eventpassfan wrote:Initially the tube on your schematic was unlabelled and I assumed had not changed....
I've been happy enough with the above values not to be motivated to start tweaking again.
Enjoy
Andy
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Re: New 4-4-0 and Asteroid 60 amp porn
Great thread(s)... I really like both of these builds and I think they are both worthy of a dedicated thread.... any chance of breaking the Asteroid off onto a separate thread? The bulk of the discussion so far is on the 4-4-0 and I didn't want to confuse matters by throwing in my comments on the Asteroid build. 
Nice work!
rj
			
			
									
									Nice work!
rj
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