Mr. Guy advice isn't to use choke in anode to avoid Tx noise also recommend tantalum resistors for anode load, answers:
1-"Best place to use chokes in a phono stage is actually in the RIAA Eq circuit. then you really are cooking.
Google LCR phono.
Not cheap to implement, look at these old 2nd hand Tango's
Tango EQ-600P RIAA LCR-Type Transformer 437A 417A Phono on eBay (end time 16-Jun-11 04:06:38 BST)
Needs a very special circuit around it for it to work well.
Hopefully the big brother of the P10 will be based on this type of circuit.
rgs
Guy"
2-I didn't quite get how the mosfet shunt reg was going to take the place of the load resistors! I assumed your friend did.
The P10's gain stages are both very conventional, there's nothing special or unusual about them or the way they need their HT voltage delivered. Incidentally I can supply a replacement P10 HT transformer if you need one although you may well choose to go larger.
I still think you could have fun with a valve shunt regulator running the HT and make use of that otherwise overspecced choke.
You should also use a valve rectifier if you can. You'll need a transformer with maybe 280-0-280 @100mA, a 5V3A winding for a GZ34 and another 6.3V3A winding for the shunt reg valve. I'd use a 6080. You'll also need 2 more octal bases and 2 B7 bases for glow tubes.
1-"Best place to use chokes in a phono stage is actually in the RIAA Eq circuit. then you really are cooking.
Google LCR phono.
Not cheap to implement, look at these old 2nd hand Tango's
Tango EQ-600P RIAA LCR-Type Transformer 437A 417A Phono on eBay (end time 16-Jun-11 04:06:38 BST)
Needs a very special circuit around it for it to work well.
Hopefully the big brother of the P10 will be based on this type of circuit.
rgs
Guy"
2-I didn't quite get how the mosfet shunt reg was going to take the place of the load resistors! I assumed your friend did.
The P10's gain stages are both very conventional, there's nothing special or unusual about them or the way they need their HT voltage delivered. Incidentally I can supply a replacement P10 HT transformer if you need one although you may well choose to go larger.
I still think you could have fun with a valve shunt regulator running the HT and make use of that otherwise overspecced choke.
You should also use a valve rectifier if you can. You'll need a transformer with maybe 280-0-280 @100mA, a 5V3A winding for a GZ34 and another 6.3V3A winding for the shunt reg valve. I'd use a 6080. You'll also need 2 more octal bases and 2 B7 bases for glow tubes.
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I don't asked but his memory remember a very good phono RIAA using valves shunts reg & LCR transformers
Not as a plate load. As a regulator for the correct B+, and not skipping the plate load, it will work fine.
I know it seems like a totally crazy idea, but why not build it as designed, get it working, and then start experimenting?
Someone had an SRPP or Mu Follower working directly off the reg and are expecting a common cathode to do the same most probably.😉
I used Salas schematic so I added 68K & 4.7uF instead 3.3uF to drop till 220V but the voltages measurements are:
CCS 260V both channels
ECC83
between 120K & 68K must be 220V and I have
L 206V
R 206V
between 120K & C10 must be 150V and I have
L 129V
R 133V
ECC88
between 39K & C2 must be 80V and I have
L 100V
R 102V
Of course I don't have sound so don't works.
CCS 260V both channels
ECC83
between 120K & 68K must be 220V and I have
L 206V
R 206V
between 120K & C10 must be 150V and I have
L 129V
R 133V
ECC88
between 39K & C2 must be 80V and I have
L 100V
R 102V
Of course I don't have sound so don't works.
Making progress!
The DC voltages seem OK. Time to do some circuit tracing and see where the signal gets lost. Inject a signal into the input of about 5-10mV at 1kHz. Using a scope or your meter set for AC, see if there's AC voltage at the first stage anode. If yes, do the same at the second stage anode.
The DC voltages seem OK. Time to do some circuit tracing and see where the signal gets lost. Inject a signal into the input of about 5-10mV at 1kHz. Using a scope or your meter set for AC, see if there's AC voltage at the first stage anode. If yes, do the same at the second stage anode.
Sorry for my ignorance, wich pin heater is the positive & negative for ECC83 because original Puresound as soldered togheter pin 4 & 5 to one heater & pin 9 to the other heater, I mind positive heater is 4 & 5 togheter?
It doesn't matter much as long as you have a nice, reasonably quiet 6V. Pick either.
If the heater voltages aren't elevated above ground, once you have things working, you may want to do this.
If the heater voltages aren't elevated above ground, once you have things working, you may want to do this.
Hi,
You may wish to review the Phonostage my Evil twin posted in the DC-Phono Thread and related ones. These two threads may be of use:
http://www.diyaudio.com/forums/tubes-valves/28957-dc-phono.html#post335624
http://www.diyaudio.com/forums/tubes-valves/54534-kofi-annan-b-plus.html
There is much material on various areas.
TBH, looking at the P10 I see many areas of sub-ideal implementation.
For the PSU, with or without Maplin Choke, you can use Duncanamps PSU-Designer to work backwards. The PSU for my evil twins Phono should probably also work fine.
My biggest issues would be the cathode bypasses. They really are not needed and do not help sound quality.
I would suggest to run the first stage with an unbypassed cathode resistor, which will much stabilise the anode impedance against tube variations, just as I do, a bit more current and a lot less Voltage in practice I found reduces noise.
Using gridleak Bias on the second stage allows to get rid of that cathode cap, the ECC88/6DJ8 after all was designed for gridleak bias.
In the first stage an anode load choke is not useful (it would need a VERY large amount of inductance anyway, the second stage could use a Tango TC-160-15W (160 H, 15 mA, 1160 ohms) anode choke, or a CCS. In the commercial implementation of my circuit (the diyhifisupply.com Cole Phono) a Ixys 10M45 CCS was used.
Ciao T
You may wish to review the Phonostage my Evil twin posted in the DC-Phono Thread and related ones. These two threads may be of use:
http://www.diyaudio.com/forums/tubes-valves/28957-dc-phono.html#post335624
http://www.diyaudio.com/forums/tubes-valves/54534-kofi-annan-b-plus.html
There is much material on various areas.
TBH, looking at the P10 I see many areas of sub-ideal implementation.
For the PSU, with or without Maplin Choke, you can use Duncanamps PSU-Designer to work backwards. The PSU for my evil twins Phono should probably also work fine.
My biggest issues would be the cathode bypasses. They really are not needed and do not help sound quality.
I would suggest to run the first stage with an unbypassed cathode resistor, which will much stabilise the anode impedance against tube variations, just as I do, a bit more current and a lot less Voltage in practice I found reduces noise.
Using gridleak Bias on the second stage allows to get rid of that cathode cap, the ECC88/6DJ8 after all was designed for gridleak bias.
In the first stage an anode load choke is not useful (it would need a VERY large amount of inductance anyway, the second stage could use a Tango TC-160-15W (160 H, 15 mA, 1160 ohms) anode choke, or a CCS. In the commercial implementation of my circuit (the diyhifisupply.com Cole Phono) a Ixys 10M45 CCS was used.
Ciao T
Thanks for help, sorry I'm newbie could you elaborate:
-1st stage connect the cathode directly to gnd without resistor & bypassed capacitor?
-How implement gridleak Bias for ECC88
I use Salas HV shunt reg CCS for both tubes
Hi,
Look at the schematic in the threads referenced (posted by Kuei Yang Wang), it shows it all.
No extra filter between ECC88 stage and ECC83 Stage? Possibly not the best idea.
Equally, I would consider using one regulator per channel, Salas Shunts are good, but not that good.
Ciao T
Look at the schematic in the threads referenced (posted by Kuei Yang Wang), it shows it all.
No extra filter between ECC88 stage and ECC83 Stage? Possibly not the best idea.
Equally, I would consider using one regulator per channel, Salas Shunts are good, but not that good.
Ciao T
68K + 3.3uF between ECC88 & ECC83 to decrease B+ 260V for ECC88 till B+ 220V for ECC83
It's this schematic
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Hi,
Ok, good, 3.3uF may still be on the low side, but it is something at least.
Yes, this one.
Quite a few have build it over time and you can find comments on sound quality etc. quite easily. It was also for a time sold with minor modifications (CCS load for ECC88) as the Diyhifisupply Cole MKII...
Ciao T
Ok, good, 3.3uF may still be on the low side, but it is something at least.
It's this schematic
Yes, this one.
Quite a few have build it over time and you can find comments on sound quality etc. quite easily. It was also for a time sold with minor modifications (CCS load for ECC88) as the Diyhifisupply Cole MKII...
Ciao T
I'am happy clone Puresound P10 is working, fixed the issue: the Piccolo MC pre-pre with a cold joint in the cable between the PSU & the Piccolo
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