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Old 8th October 2012, 01:19 PM   #2111
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This is the circuit:
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Old 8th October 2012, 01:25 PM   #2112
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With 135V dc unregulated, You can use a Shunt Regulator (eg SSHV) to regulate to 105V to 115Vdc.

Or you can use RC or (better) LC filter stages to get the target ripple-level.

Please use PSUD2 to adjust the transformer voltage, rectifier type etc to suit your goals.
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Old 8th October 2012, 01:35 PM   #2113
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Thanks Rod, I tried to use PSUDII but can't get the hybrid rectifier with two UF4007 + AZ1
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Old 8th October 2012, 01:41 PM   #2114
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160V 50VA is not a typical catalogue transformer (eg off-the-shelf Hammond), so a custom wound version is usually needed.

Industrial Control Panel Trafos work really well, like this one from our local company:

50 VA

If Modena, Italia is near, please try Ideomat

Sommario visuale trasformatori monofase

Many Countries have these, and they can usually wind whatever you need. The shipping costs almost as much as this 50VA trafo, so it's best to find a local winder.

but please check that a split-bobbin is used!
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Old 8th October 2012, 01:42 PM   #2115
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Quote:
Originally Posted by merlin el mago View Post
Thanks Rod, I tried to use PSUDII but can't get the hybrid rectifier with two UF4007 + AZ1
You can just use the vacuum-brdige-rectifer model, it is quite close. Or use full-wave, the difference is less than the other errors (winding resistance, regulation etc)
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Old 8th October 2012, 02:09 PM   #2116
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I'm using a Hammond 374AXP for my B+ supply (just call me Mr Overkill). Very nice potted, steel-cased transformer, dead quiet. PSUD is attached. Choke input supply with two Lundahl LL1685 17H.

The 122.7uF final cap takes into account 100uF plus 2.7uF bypass plus 10uF per channel in the preamp box. I have what's in the PSUD in the PSU box going to the preamp box and splitting per channel to a 10uF cap, CCS at 29.5mA, VR150-VR75 bypassed with .047 Jensen copper foil, plate CCS at 7mA (runs about 132V on the plate). Sounds nice...
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Old 8th October 2012, 02:16 PM   #2117
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Funny thing is...so far I've tried the RCA 5R4GY, the Tung-Sol 5U4GB, the Mullard GZ33 and the RCA 5Y3GT - the lowly 5Y3GT sounds the best of these with a nice balance of warmth and detail. The 5R4GY has incredible detail but is a bit harsh on the highs.

With all that stuff between the rectifier and the tube, there is still a difference in the sound, even though the 26 CCS is running at 7mA and 132V in either case...

Last edited by Magz; 8th October 2012 at 02:19 PM.
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Old 8th October 2012, 03:10 PM   #2118
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Rod you have PM
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Old 8th October 2012, 03:54 PM   #2119
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Quote:
Originally Posted by Magz View Post
Funny thing is...so far I've tried the RCA 5R4GY, the Tung-Sol 5U4GB, the Mullard GZ33 and the RCA 5Y3GT - the lowly 5Y3GT sounds the best of these with a nice balance of warmth and detail. The 5R4GY has incredible detail but is a bit harsh on the highs..
There's nothing lowly about the 5Y3!! This is the same tube as the revered 80, but with an octal base instead of UX4. It's probably the best preamp tube (with the 80) unless you go into expensive stuff like the mesh plate German ones like AZ1. I use it or the 80 myself when I'm not using my small stock of mesh plate AZ1s

I use the 5R4GY for higher power duties - I prefer it to any of the GZ series, though it does have a larger voltage drop. But I tend to use two 6BY5 in parallel with a hybrid bridge for 200mA and over. Sounds very nice to me.

http://www.mif.pg.gda.pl/homepages/f...9/6/6BY5GA.pdf

Last edited by andyjevans; 8th October 2012 at 04:07 PM.
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Old 8th October 2012, 04:28 PM   #2120
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Yes Andy, all true, but the 5Y3 doesn't seem to come up in most of the online discussions of best rectifier tube. It's always the GZs, 5R4s, 274B etc. Seems like the 5Y3 doesn't get the hype the others do, but it sounds great! Still have to try my 6106 (5Y3 but it's IDH...), 5Y3WGTA and 274B (Valve Art not WE).
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