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Old 7th March 2011, 11:17 AM   #871
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Maybe I can aim for the same ballpark of cost as the filament regs - do you think that will be frugal enough??
That definitely sounds frugal to me.

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I don't like the microcontroller idea much. Won't it get a virus?
Only if it is an intel microcontroller.
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Old 7th March 2011, 11:24 AM   #872
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Bas,

a short OT. Are you at the AE open day on 19th March?
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Old 7th March 2011, 11:30 AM   #873
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Hallo Oliver,

Yes. I'm going to be there. It's only 15km away from me.
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Old 7th March 2011, 11:34 AM   #874
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Very cool

My friend John Eekels and i are also there.
He is showing his last build "Cleo 6" and "Ceasar II" amps and i am coming with my Reference TDA1541A DAC and my MAC.

I am looking forward to meet you there
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Old 7th March 2011, 11:36 AM   #875
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Very cool indeed!!!

I'm bringing Baby Huey. And Rakk dac with my active stage and SSSSR (Salas Simpler Simplistic Shunt Reg) on your board. (And a not so cool laptop
And my Bastanis Prometheus.

CU there!
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Old 11th March 2011, 02:53 PM   #876
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@ kevinkr


Just to verify if i want to use Salas HV-Shunt, Rods filament supply and perhaps the Tentlabs Autobias Module (then the 220K is canceled).


Click the image to open in full size.


Did i made any failures?
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Old 11th March 2011, 03:06 PM   #877
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V1 pin 4 and Coleman Reg negative pin shouldn't be referred to gnd AFAIK
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Old 11th March 2011, 03:25 PM   #878
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Oliver,

It is true - the Filament supply should be floating, and then ONLY connected to Ground at the tube socket.

Here's my view of the general schematic for Transformer Line Preamp - use the transformer type (Lundahl, Sowter) to suit the DHT you are using.

There's more details on connecting the Filament Supply in the PDF Manuals - sent today!
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File Type: jpeg DHTline.jpeg (80.4 KB, 1351 views)
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Old 11th March 2011, 04:39 PM   #879
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Originally Posted by Rod Coleman View Post
Hi Bas,

I've been working at a solution to the PP biasing problem, too. Maybe I can aim for the same ballpark of cost as the filament regs - do you think that will be frugal enough??

I don't like the microcontroller idea much. Won't it get a virus?
I'm in for one, please let me know how can connect it?
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Old 13th March 2011, 05:33 PM   #880
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Well, I finally tried out battery bias on the grid instead of filament bias! My impression is that I prefer it to filament bias.

That's something I need to know - it'll certainly make my life easier - no need for high current resistors and large filament transformers. It's not night and day - filament bias is good when it's really clean with choke input etc. So I'll need to do a bit more comparisons to be sure.

Right now I have battery bias on my 10y preamp into a Hammond 126C transformer. My 26 preamp with LL1660/5mA still has filament bias, and that one sounds better than the 10y preamp when it had filament bias. So next need to try the 26 preamp with battery bias.

Any preferences for an input cap? I'm using a 0.1uF Russian silver mica. I also have the Russian teflon ones of various kinds I could try - thinking FT-2.

Andy
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