He was referring to this one -->
http://www.diyaudio.com/forums/power-supplies/192625-sslv1-1-builds-fairytales.html
As far as I can recall Salas gave permission to Quanghao to do those boards. Also, in the past, when someone did not want their circuits boarded by Quanghao, he respected the author's wish.
Salas,
I have got another (nonexpert) question for you...
I am running one of my HV shunt regs (still the older version) in my transformer coupled C3G headphone amp for 9 months or so...
It is still on the breadboard but will be cased up in the next months and will also receive the SSHV reg with one of the boards
of dvb-project (more compact).
Directupload.net - Dtbv74e8i.jpg
I remember from the thread that somebody said that the shunt reg will not like to "drive" output transformers = inductance.
Well, the amp is performing quite nice but sports a very slight harshness that initally I thought was the schematic in general or else.
I now noticed that the shunt Mosfet gets warm rather quick even though I only have about 30V Vin - Vout, CCS set to about 80mA,
32mA into the load. I suspect I am having oscillations... right?
Of course there is no scope here to prove it... but is there something I can try to better my situation? I could convert to parafeed
with smallish coupling caps (~ 4.7uF) if there is no other chance. Also: would the shunt reg like to drive a Ultrapath connection
(3.9uF russian oilers to the cathode) with my SE output transformers?
As usual, any thoughts are very appreciated!
Interesting...
I use a similar C3g stage as output for a AD1865 Dac and a Lundahl 1660 SE transformer fed by a SSHV board from Quanghao. Blessed with ignorance I threw in a 20µF Ultrapath cap to the cathode, and the sound became even better. The current mosfet becomes pretty hot though, current is about 70mA with around 28 mA to the tubes and just 15V Vin - Vout.
Having no scope, I can't measure oscillation, but the whole thing seems to be rather stable and there is definitely no trace of harshness. A little noise is there when full Volume with my horn speakers, maybe comes from the birds nest it still is on the breadboard.
Maybe you can try 150-160V for anode, as the C3g seems pretty sensitive to changes of anode Voltage. With 170V/15mA it sounds a bit dry and mechanical, less current brings down the high freq a little. I settled to 160V/14mA in my setup.
Probably I try a smaller Ultrapath, I have some 4,7 Siemens MKV around, maybe they put less stress on the reg.
BTW the C3g is a wonderful tube, didn't expect that kind of sound with a Dac...
Cheers,
Juergen
Yes, for the group buys. Those on shop must be left overs. I did not give infinite time OK for using my nick name for products though. The regs are going to get new and official boards anyway. Quanghao was OK for making the regs available and helped. No problem for those older versions.
To check for oscillations without a scope, bring an AM radio near the regulator and play around with the receiver frequency, while moving the radio around (closer and further) the regulator. You should be able to pick the oscillations and by turning the regulator on/off you can see if it's the real source.
You could always tell him to take them off if you don't agree. He was quite reasonable in the past and did respect my wish of not doing anything with my stuff.
Hi Juergen, thanks for joining!!
I will try lower anode voltage since it is so easy to change with the Salas reg...
I will also have to go a bit bigger with the Cathode resistor (~180R).Thanks for your experience with the Ultrapath in your C3G output stage... wanted to try that for a long time. I do have the aforementioned russian PIO and also Siemens MKV... when only they were not so big...
I am suspecting oscillations more due to the fact that the shunt Mosfet gets warm relatively quick which I didn't notice in other builds with similar load.
And yes, and not wanting to derail the thread, C3G is a wonderful tube! My first experience was with the ubiquitous Siemens Headphone amp on Jogis Roehrenbude (and it can be seen there), but I felt that it could sound better using opt's and the shunt reg.
Iko, that is a very cool hint. Will try, jut have to find a radio (in the days of digital everything
).
I did a point to point wiring of Salas's regulator !!!
It works and plays very well for my 6SN7 pre amp.
Saving the cost of choke and expensive filter cap. I use 57 ohms for R1 so the CCS current is 34ma approx. and fed by 360V raw DC, out at 300V for two 6SN7. The total current consumed by this pair tube approx. 16ma and I tried to tripple the supply but it's getting hot !!!! I just use the chasis cover for heat sinking so I go back to double the value only.
Salas, would you tell me the latest version that I can make further improvement ? Because the discussion is very long .... ha ha ha
Thanks Salas.
It works and plays very well for my 6SN7 pre amp.
Saving the cost of choke and expensive filter cap. I use 57 ohms for R1 so the CCS current is 34ma approx. and fed by 360V raw DC, out at 300V for two 6SN7. The total current consumed by this pair tube approx. 16ma and I tried to tripple the supply but it's getting hot !!!! I just use the chasis cover for heat sinking so I go back to double the value only.
Salas, would you tell me the latest version that I can make further improvement ? Because the discussion is very long .... ha ha ha
Thanks Salas.
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Truly unique build. The BC transistors first reg in direct to chassis dead bug wiring! Are you sure you want to dismantle that for a later update?
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