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Old 29th December 2011, 03:28 PM   #1451
regal is offline regal  United States
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One more #26 pre finished.
This time I used filament bias, instead of battery. Getting rid of the input cap was nice. Also, ll1660pp output transformers, Intact audio autoformers at the output for volume control. Heater regulators by Rod, and double latest Salas design SSHV2 for voltage regulation.
There is big change in sound to the better from the one I had before with battery bias. Mainly it seems clearer and more dynamic. I like it a lot!
With Rod's kits the filament bias seems the way to go, I mean you eliminate an input transformer/cap and don't need a cathode bypass cap, I imagine there is a limit to how much vou can have across the regulator outputs as far as using the cathode resistor in series with the cathode as the load ?
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Old 29th December 2011, 03:38 PM   #1452
vgeorge is offline vgeorge  Greece
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Rod can tell you more about the limits of his regulators. In my build, I have vin 17.5V and 11.4Vout.
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Old 29th December 2011, 03:58 PM   #1453
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Originally Posted by vgeorge View Post
Rod can tell you more about the limits of his regulators. In my build, I have vin 17.5V and 11.4Vout.
Hi George, Looks like good layout and build!

Voltage Rating for Filament Bias:
With correctly specified C1 and R8, any new kit can be configured to run Filament bias up to 45V or so at the input.

With changes of transistor 200V is possible - though I can't imagine it is needed.
Flexible operating voltage - the beauty of discrete-transistor design! New V4 kits are available for Filament bias.
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Old 29th December 2011, 05:38 PM   #1454
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Quote:
Originally Posted by vgeorge View Post
One more #26 pre finished.
This time I used filament bias, instead of battery. Getting rid of the input cap was nice. Also, ll1660pp output transformers, Intact audio autoformers at the output for volume control. Heater regulators by Rod, and double latest Salas design SSHV2 for voltage regulation.
There is big change in sound to the better from the one I had before with battery bias. Mainly it seems clearer and more dynamic. I like it a lot!
Wow George, there is more difference using one or two SSHV2 regs instead one?
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Old 29th December 2011, 05:51 PM   #1455
vgeorge is offline vgeorge  Greece
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I think that difference is small, based on my previous build, but this is DIY, so why not overdo it?
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Old 29th December 2011, 05:57 PM   #1456
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I asked you because I have two Bartolucci tx 125VDC & two Bartolucci choke 10H 100mA

Andy & others when I asked to do a dual B+ with Salas regs told me that isn't necessary but my idea is like you did.
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Old 29th December 2011, 06:30 PM   #1457
vgeorge is offline vgeorge  Greece
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I assume tx 125Vac, which seems a kind of small. What B+ do you aim for?
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Old 29th December 2011, 06:41 PM   #1458
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What B+ are you using?
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Old 29th December 2011, 06:48 PM   #1459
vgeorge is offline vgeorge  Greece
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B+ 182V, 160V after regulator, 140 on anode. Tx is 2x220V.
Maybe your tx is 2x125V, so you can put secondaries in series?
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Old 29th December 2011, 06:52 PM   #1460
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That's will be a solution because I have two 125VAC. My choke only have 10 ohms so it's possible that after the choke I will have 170VAC or more, initially I targeted 150V for B+ on anode & you have 140 on anode.
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