That must be it.
I've got all active parts used in the BT, including V-grade J72/K147s for a 60dBV gain MC phono stage, but i'm no expert so i'll skip copying the CTC but steal JC's ideas for the one pre-amp that i am assembling.
Me thinks JC has been so informative and made so many tongue slips and slides that someone can build an updated and economical basic version from this thread.
Only thought that occupies my head is how to steal his 944 and how he did the RIAA in the phono board.
I've got all active parts used in the BT, including V-grade J72/K147s for a 60dBV gain MC phono stage, but i'm no expert so i'll skip copying the CTC but steal JC's ideas for the one pre-amp that i am assembling.
Me thinks JC has been so informative and made so many tongue slips and slides that someone can build an updated and economical basic version from this thread.
Only thought that occupies my head is how to steal his 944 and how he did the RIAA in the phono board.
jacco vermeulen said:
Jacco,
I respectfully disagree. There is MUCH more to John's creations than a component value here or there. No way anybody builds a BT-quality preamp from this thread!
Now, as for stealing his 944, mmmmm..
But then again, I remember coming back with Hugo from the UKdiy2007, low-flying down the M20 towards Dover, tailing that ashblond beauty in the Porsche Cayenne, weaving through traffic at 100+ mph, we with the top down on the A4, man, who needs a 944??
Jan Didden
carlmart said:
Means you are late.
From the picture of the line stage that was posted at tgaudio the resistor values can be read like the palm of your hand.
All but the 4 vertical upright in-series pairs of HolCo R's at the sides of the RelCaps, but those should be obvious.
Same goes for the PS board, JC even handed the specs of the transformer, unless you desire the make of the auxiliary transformer and relays as well.
Even with a BT schematic it's not entirely clear how the Zuffenhausen guy does his fet matching routine.
Hi, Carlos, Hi, PMA, Hi Jacco,
One doesn't need schematics to be able to have a fairly good reverse job done. Already done that with some John Curl's things... Some good pics are OK... But yes, Blowtorch are admittedly blurred...
Like Jacco said, it is easier from good pics (can drop me a line, Jacco... Will try to help...).
And PMA is absolutely right, Carlos... You little dug the Blowtorch question here.
Some questions remains (at least to me !) that would lead to a schematic, without asking John any :
John,
About PSU :
- you advocated against LM 317s family, but with JCMD thread, almost all forumers understood that you used them on the Blowtorch PSU... Not actually what you developped...
- what is a "car battery" like supply for you ? (60 milliohms impedance or less ???),
About the Line amp :
- you advocated "post servo" attenuators (1/10 to 1/100 ratio...). But no one can bee seen on the PCB (= underside the PCB, or even underside the op-amp sockets ?),
- the Line has open loop Jfet stage input (here much more seen as an impedance Xformer, with NO gain. ....), low feedback Mosfet (gain = 8dB) stage, and no overall feedback...
Right ???
With some thinking, cross exchanges, and lot of reading around, nobody really needs a schematic...
So, Carlos, just enjoy the questions, add yours, beg explanations from forumers/designer, and ALSO go others forums... And read back from the beginning.... A lot to gain too...
Cheers,
Jbaudiophile
One doesn't need schematics to be able to have a fairly good reverse job done. Already done that with some John Curl's things... Some good pics are OK... But yes, Blowtorch are admittedly blurred...
Like Jacco said, it is easier from good pics (can drop me a line, Jacco... Will try to help...).
And PMA is absolutely right, Carlos... You little dug the Blowtorch question here.
Some questions remains (at least to me !) that would lead to a schematic, without asking John any :
John,
About PSU :
- you advocated against LM 317s family, but with JCMD thread, almost all forumers understood that you used them on the Blowtorch PSU... Not actually what you developped...
- what is a "car battery" like supply for you ? (60 milliohms impedance or less ???),
About the Line amp :
- you advocated "post servo" attenuators (1/10 to 1/100 ratio...). But no one can bee seen on the PCB (= underside the PCB, or even underside the op-amp sockets ?),
- the Line has open loop Jfet stage input (here much more seen as an impedance Xformer, with NO gain. ....), low feedback Mosfet (gain = 8dB) stage, and no overall feedback...
Right ???
With some thinking, cross exchanges, and lot of reading around, nobody really needs a schematic...
So, Carlos, just enjoy the questions, add yours, beg explanations from forumers/designer, and ALSO go others forums... And read back from the beginning.... A lot to gain too...
Cheers,
Jbaudiophile
O segredo é a alma do negócio... secret is important
fine that.
This turns people crazy.
O segredo constuma ser melhor, e mais complicado, que a realidade vai mostrar... viva a mistificação e o mito.
The secret use to be better, also more complicated, than the reality will show... hurra to our imagination.... nice our Myths.
Carlos
fine that.
This turns people crazy.
O segredo constuma ser melhor, e mais complicado, que a realidade vai mostrar... viva a mistificação e o mito.
The secret use to be better, also more complicated, than the reality will show... hurra to our imagination.... nice our Myths.
Carlos
analog_sa said:You may want to check post 1628 out for schematics. JC also needs them
Now I've got it!
JC designs the equipment, then throws all schematics aways so it's not stolen and that's it! Perfectly safe.
But he didn't count, as we did not, with Dr. A's attack on our memory as we get er... more experienced...
The JC-80 was designed in 1982 or so. It is more than 25 years old. You can put those schematics up, if you have them, and some audiophiles might have them. However, my JC-80 schematics, which are within reaching distance are not on my computer and I have no reason to put them there. It is the CTC Blowtorch schematic that I will not specifically divulge, as it is still an ongoing design.
Why you people make so much of things is beyond me. Why speculate so much. Why demand schematics? I don't owe you a schematic. I actually get paid for generating schematics, but you want it for nothing.
Why you people make so much of things is beyond me. Why speculate so much. Why demand schematics? I don't owe you a schematic. I actually get paid for generating schematics, but you want it for nothing.
Hello, Pavel,
Yes, it would have been what I would have done if I was John Curl himself... And I know how far your advice is a valuable one !
But John used too little parts (as seen on the bad pics).
I would just advocate a scheme like the attached one, with perhaps
2 low voltage Zener diodes seried (remember John's course about them?) in order to get approximately a 6V... 6.6V reference... Just running experiments here to see if the "Zener zone" noise is easier to remove than the "Avalanche zone" one... And yes, I know that a LM329 would be far easier to use...
Also, a far bigger Mosfet than IRF, and a SERIOUS resistor to ground BYPASS (I just turn to be more obsessed with RFI you are an expert dealing with..). IMO, the room between reservoir caps and series regulation is the right place to fight against the more poweful, and when it is too tired (some 60 dB attenuated at least), common mode coils would help to remove same phase same amplitude unwanted RFI... Right ?
After the series regulation, should be only DC voltage (or the less AC as possible...). And I really love simple schemes...
Inputs from forumers that have experimented with that are welcome...
Jbaudiophile
Yes, it would have been what I would have done if I was John Curl himself... And I know how far your advice is a valuable one !
But John used too little parts (as seen on the bad pics).
I would just advocate a scheme like the attached one, with perhaps
2 low voltage Zener diodes seried (remember John's course about them?) in order to get approximately a 6V... 6.6V reference... Just running experiments here to see if the "Zener zone" noise is easier to remove than the "Avalanche zone" one... And yes, I know that a LM329 would be far easier to use...
Also, a far bigger Mosfet than IRF, and a SERIOUS resistor to ground BYPASS (I just turn to be more obsessed with RFI you are an expert dealing with..). IMO, the room between reservoir caps and series regulation is the right place to fight against the more poweful, and when it is too tired (some 60 dB attenuated at least), common mode coils would help to remove same phase same amplitude unwanted RFI... Right ?
After the series regulation, should be only DC voltage (or the less AC as possible...). And I really love simple schemes...
Inputs from forumers that have experimented with that are welcome...
Jbaudiophile
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