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Re: Principle schematic [message #30419 is a reply to message #30418] Sun, 06 February 2005 08:11 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I like that. I think it might make a nice power amp that's fairly simple to build.

I think I'll probably build something like that when I build the Guinevere. I'll probably forego the FET CCS on the driver tube and preamp, maybe add it later. That's how I built the Paramours too - First with a resistor in the plate circuit to B+ and then later with the CCS.

I like how the 2A3 sounds, and I like the glow. One of these times, it might be fun to build a 2A3 push-pull amp too. Lots more oomph, and that's important when playing orchestral music or other material with a lot of range, even with 100dB+ horns. But for starters, I like the SE 2A3. It's simple and it sounds good.

No harm having both an SE power amp and a push-pull amp group build project going at the same time.


Re: Principle schematic [message #30420 is a reply to message #30419] Sun, 06 February 2005 09:33 Go to previous messageGo to next message
Damir is currently offline  Damir
Messages: 1005
Registered: May 2009
Illuminati (2nd Degree)
Of course. I`m slow and don`t have too much time, but I hope that soon enough I`ll breadboard the simple version of that amp. I have a few 6B4G and other parts, except DN2540. But I have the parts for MJ350 based CCS (from M. Jones book, similar to C4S-Bottlehead).
Probably I`ll try 5687, E182CC and 6J5GT for the driver.
For those who likes "passive" solution, I noticed "Lundahl" LL1667 line of anode chokes, for example 7ma/580H, 10mA/405H, 15mA/270H - just what we need, but the price is not low...
To be continued (I hope :-))...

Re: Principle schematic [message #30422 is a reply to message #30420] Sun, 06 February 2005 09:47 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)
I'll try those Lundahl chokes first, then maybe go with a CCS and compare the difference. Thanks!

Re: you don't want to see what *I* thik is complex... [message #30424 is a reply to message #30416] Sun, 06 February 2005 13:21 Go to previous messageGo to next message
cheetah is currently offline  cheetah
Messages: 70
Registered: May 2009
Viscount
I still like the idea of a PP 6V6 or for a little more power, 6L6. These are good tubes. The Iron foe a stero amp is inexpensive. One could use a SE input stage and use an IT to do the phase splitting, or use a PP input stage and do the phase splitting at the input. Total cost for these, with decent parts would be approx, $500 to $600. The results would be killer.

Joe

the Poinz... [message #30425 is a reply to message #30424] Sun, 06 February 2005 16:14 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)

Poinz drew this of my E-Linear circuit. 10k a-a with screen taps at 20% for the 6V6 and a 6BQ7 up front will sound brilliant. Try it with 40% taps for 6L6's. B+ in the mid 200's and run class A bias. 807's are another option too. Or get the OPT wound with 20, 30, and 40% taps and perform your own experiments.

Small negative rail for fixed bias will double as a sink rail for a CCS instead of the resistor and requisite larger neg. rail shown in the schematic.

The grid chokes are just as easy to do as a proper output TX.
regards,
Douglas



Oh baby!!! [message #30426 is a reply to message #30425] Sun, 06 February 2005 18:56 Go to previous messageGo to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
This with 807's would be too cool. I'm in.....Colin

Re: the Poinz... [message #30427 is a reply to message #30425] Sun, 06 February 2005 19:43 Go to previous messageGo to next message
cheetah is currently offline  cheetah
Messages: 70
Registered: May 2009
Viscount
Very Nice!

I like the idea of using a smaller Bias supply and a CCS on the input. One could even use a grid choke in place of input resistor, if they wanted to go over the top.

And the price: $1.90 for a 6BQ7 @ AES, @2.90 @ Uncle Neds. Matched pair of JJ's $30. @ Uncle Neds.
Center tapped grid choke could be PSA-2N(nickel) from Elecrtra-Print.

Joe



Re: the Poinz... [message #30428 is a reply to message #30427] Sun, 06 February 2005 20:39 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
tell me more of this CT grid choke from E-P please. I have one of my own design which I like. Always ready to explore new stuff though.
regards,
Douglas

Re: the Poinz... [message #30429 is a reply to message #30428] Sun, 06 February 2005 20:49 Go to previous messageGo to next message
cheetah is currently offline  cheetah
Messages: 70
Registered: May 2009
Viscount
There isn't much info at the Electra-Print site. But I'm sure Jack @ EP can give you the details.

You can find out a little more @ Chris Beck's site. Follow the link attached.

What I know is this, The EP amp uses this as a phase splitter. It is a center tapped choke. Core is nickle. Very nice for low drive levels. Since your amp would not use it this way, the nickle core should be a nice touch.

Joe

Re: the Poinz... [message #30430 is a reply to message #30429] Sun, 06 February 2005 20:50 Go to previous messageGo to previous message
cheetah is currently offline  cheetah
Messages: 70
Registered: May 2009
Viscount
Here's the link

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