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SE Iron... [message #11039 is a reply to message #11037] Thu, 03 March 2005 15:55 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
We should perhaps enlist Jack at E-P to specially tap some g2/E-Linear OPTx's. Perhaps a few taps so soem experimetation can be carried out to adjust for personal taset/system synergy.

I am departing the low power arena, and considering Maggies. Going to demo a pair of the 1.6's soon. I worked with my Pop, and we came up with a tentative PP 813 amp. Full pentode rigging for the finals. ~100W w/o leaving the comfy, house heating bounds of Class A, or using loop NFB.

It will take a sepcial OPTx to do it, and I *MAY* have just the ticket!

And another thing to increase complexity. All DH valves. not a cathode sleeve among them. Lotsa glow!
regards,
Douglas

Re: for beginners [message #11040 is a reply to message #11038] Thu, 03 March 2005 21:40 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Check out the Group Build forum. Lots-O-Stuff happening there.


Re: SE Iron... [message #11041 is a reply to message #11039] Thu, 03 March 2005 21:41 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Cooooool!

I've got to see and hear that!


but back to SE... [message #11042 is a reply to message #11039] Sat, 05 March 2005 09:50 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
THe E-Linear circuit is sweet. It is not restricted to pentode finals. All amps can use some well applied NFB to good effect IMO/IME.

The thing to do is get custom Iron with ~4k primary, and tap it at 10%, 20% and 40%. Tehn there is the pate z of the driver to modify the ampunt of NFB on top of tap %-age. lowe pate z means less NFB. Pentodes and the faux pentode cascode connnection delive the highest fraction due to the high plate z( horizontal plate lines, no? ).

L-C-L-C is probably the best idea for the PS. Good input choke in first pos'n, and a low DCR, low Hy for the second. Moror run oilers for PS caps. Rectifiers? too many choices. Hg-vapour? DH like 5R4's? IDH like 5AR4, or single diode like the damper diodes of 6AU4 ilk?

It always comes back to the custom OPTx, you need the taps where you need them, so might as well get a few and be able to mod the amp and/or experiment.
regards,
Douglas

Re: but back to SE... [message #11047 is a reply to message #11042] Wed, 16 March 2005 18:08 Go to previous messageGo to next message
Thatch_Ear is currently offline  Thatch_Ear
Messages: 16
Registered: May 2009
Chancellor
I agree that NFB can be nice at times. An interstibg solution is to use a stepped attenuator in the feedback loop so that you can adjust the feedback, or have none at all. I was shown how vocals sound better with feedback but an acoustic guitar can sound better with none. It is nice to have it both ways.

Re: but back to SE... [message #11048 is a reply to message #11047] Wed, 16 March 2005 18:27 Go to previous message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
absolutely. It also depends on methods of applying NFB. In a PP circuit I am quite the opinion that the NFB ought to be PP or balanced as well. That requires the rest of th amp be built PP. So this puts certain constraints on the design.

A variable amount is another nice trick. I think that my opinion of what is the best changes from recording to recording. Let alone week to week. It does stay fairly centered about a general level though...
regards,
Douglas


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