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Old 16th October 2010, 10:26 AM   #651
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Quote:
Originally Posted by merlin el mago View Post
Thanks so much.

Sorry for my ignorance what are OA2 & OB3 in the schematic? Wich tubes do you recommend for 5Y4GT & 26?
OA2/OB3 are Zener tubes used to regulate the B+. You don't need those if you use SALAS HV PSU for B+. Ignore the power supply in my schematic fully if you are planing to use SALAS and replace that part with SALAS PSU.

I strongly recommend to use type 80 over 5Y4 or 5Y3 for the rectifier or if you could find a mesh plate AZ1 as someone recommended in this thread. Brand of the tube could be anything of US or UK made once.

For 26, I liked Silvertone, Sylvania and Cunningham over others.
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Old 16th October 2010, 10:29 AM   #652
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[QUOTE=regal;2334320]
Quote:
Originally Posted by coolzero View Post
Below is the link for my existing gird bias schematic.
QUOTE]

I'm not sure the battery grid bias would work with Colemean's filament supply, has anyone tried this?
Regal, I fixed Rod's fil.PSU to my gird bias 26. It is working so far perfectly without an issue. Rod advised me to ground the supply only at the 26 pin (1 or 4). I think this is the only concern.

Last edited by coolzero; 16th October 2010 at 10:36 AM.
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Old 16th October 2010, 10:30 AM   #653
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Quote:
Originally Posted by coolzero View Post
OA2/OB3 are Zener tubes used to regulate the B+. You don't need those if you use SALAS HV PSU for B+. Ignore the power supply in my schematic fully if you are planing to use SALAS and replace that part with SALAS PSU.

I strongly recommend to use type 80 over 5Y4 or 5Y3 for the rectifier or if you could find a mesh plate AZ1 as someone recommended in this thread. Brand of the tube could be anything of US or UK made once.

For 26, I liked Silvertone, Sylvania and Cunningham over others.
Thank you again
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Old 16th October 2010, 04:29 PM   #654
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Quote:
Originally Posted by coolzero View Post

Regal, I fixed Rod's fil.PSU to my gird bias 26. It is working so far perfectly without an issue. Rod advised me to ground the supply only at the 26 pin (1 or 4). I think this is the only concern.
Battery bias, fixed bias, cathode bias - any bias method works with the new Regulator.

As Kanishka says, you just have to be sure to only have ONE ground return for the anode current - pin 1 or 4 of the tube socket.
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Old 17th October 2010, 06:38 AM   #655
regal is offline regal  United States
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Somewhere I remember reading that CCS differential topology reallly helps to work with the #26 to reduce hum. Has anyone tried this? What would be the technical reasons this topology would be ideal?
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Old 17th October 2010, 09:04 PM   #656
Kriskom is offline Kriskom  Indonesia
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Hi Coolzero,
Go to the German Ebay site : eBay: Neue und gebrauchte Elektronikartikel, Autos, Kleidung, Sammlerstücke, Sportartikel und mehr ? alles zu günstigen Preisen
then search for AZ1
Yu can see various AZ1 , then solid plates and the meshplates.

Yu also can use the AZ11 or AZ12 in liaue of the AZ1. they hav the same specs.

Thou the AZ solidplates are superior to the "standard" retifiers tube (ie. GZ34/32, 5AR4, 83V etc..) the AZ solid plates are significantly way behind the meshplates.

Paul
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Old 19th October 2010, 10:52 AM   #657
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I would like to buy Rod's filament PSU unit. Is there a way to contact Rod? I didn't see a way to PM or email him.
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Old 19th October 2010, 11:04 AM   #658
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I'll send some PM to you now.
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Old 24th October 2010, 05:24 PM   #659
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Hi,

I have fixed Rod's filament PSU, rewired my pre amp and it sounds great now. But one small issue remains it seems. I noticed that my speaker cones are rumbling even when there is no input signal provided. No audible hum at the moment from the speaker unless I keep my ears very close to the speakers. My speaker are with 90 DB/111 SPL sensitivity. With doubts, I checked the pre out using a multimeter and observed a little bit of residual DC. I assume the speaker rumble is because of the DC coming out of the pre. All my coupling caps are brand new Mundorf hence I wouldn't expect any sort of leak from those. Is my assumption correct? Or else, is there any other reason for this? How I can get rid of this issue? Appreciate your advice as usual.

Last edited by coolzero; 24th October 2010 at 05:28 PM.
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Old 24th October 2010, 05:38 PM   #660
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I checked the pre out using a multimeter and observed a little bit of residual DC :
can be a fake reading...try misure dc current.
I haved problem with pumping cone changing psu coke with hight resistence in my tube amp,ie the clc frequency of psu ....
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Last edited by nicoch58; 24th October 2010 at 05:42 PM.
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