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Old 14th December 2002, 07:07 PM   #11
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Fair enough. Actually, it's not so much transparency i worry about. All my tube creations use a separate tube rectified PS per stage. I simply refuse to accept that two stages could possibly share the same supply. Well, maybe a really good, possibly shunt regulator may replace the separate supplies but i still haven't had luck with one. All this contributes significantly to the weight and i'm not so young and strong any more

cheers

peter
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Old 14th December 2002, 07:26 PM   #12
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Default PSU+SHUNT REG

Hi Peter,

Quote:
I simply refuse to accept that two stages could possibly share the same supply.
Neither do I.
What I do is use a tube shuntreg per stage in the amplifier bar the outputstage unless it's low power.

In a phonopreamp I would take that even further and use separate Xformers,rectifiers and shuntregs on per stage basis.
All this hardwired,stargrounded and on a dual mono basis.
The PSU gets a dedicated chassis as well.

It is my recipe for a realistic soundstage combined with very high resolution and bass you wouldn't believe till you heard it.

Cheers,
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Old 14th December 2002, 07:49 PM   #13
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Frank

do the shunt-regs allow you to get rid of all chokes? i am still concerned 'bout my ageing back. Care to describe in general terms your regs topology and shunt tube type? I am just about to fully redo my phono and very keen on weight reduction, don't even ask me how many chokes are there currently (that's since i found a choke in each PS ground line greatly contributes to groovy bass)

peter
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Old 14th December 2002, 08:12 PM   #14
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Default PSU REG

Hi Peter,

Well,this will make your aching back very happy.

For instance for a B+ of roughly 300V I often use a trioded EL86/6CW5 as a series element.
A ECC83/12AX7A as a dual stage error amp and in this example a OG3/85A2/5651 glowdischarge tube as a reference.

If you want the get rid of the chokes the "ripple killer"* circuit should do the trick as you can put some serious caps between its' output and the shunt reg.
Behind the regs (contrary to common belief that you can't) I still put some heavy caps behind the reg.
Never,ever saw the voltage sag,this is a rock stable PSU with exceptional PSURR.

For higher voltages you can use the OA2.
A more economical alternative for say 250V B+ could be built around the ECL85.

*RIPPLE KILLER
**
NOTE:I personally never built this circuit but from what i see it should work,it uses a 12AT7A/ECC81

Btw,did you use chokes in both B+ and ground rails?

Ciao,
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Old 14th December 2002, 09:07 PM   #15
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Frank,

Thanks for the chiropractic tips. Yes, i use a separate choke in B+ and the centre tap of the transformer. Not so much to kill ripple, but for the rhytm and control in the bass.

cheers

peter
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Old 29th December 2002, 02:09 PM   #16
Joel is offline Joel  United States
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Default finished

Finally got around to finishing the first amp. Sounds very very good, but that was to be expected...
Here are some pics, although I have yet to mount the bottom plate and rubber feet.
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Old 29th December 2002, 02:11 PM   #17
Joel is offline Joel  United States
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Default side view

you can see the little metal 5W4 in this one...
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Old 29th December 2002, 02:12 PM   #18
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Default JOLLY 71A

Hi,

Nice work Joel!

BTW,did you find out more on that post you lost?

Cheers,
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Old 29th December 2002, 02:12 PM   #19
Joel is offline Joel  United States
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Default top

another, from the top.
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Old 29th December 2002, 03:56 PM   #20
dhaen is offline dhaen  Europe
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Default Nice work Joel

Are those (non magnetic) brass screws I see? Or is it a trick of the light.
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