This is also regarding the post by Darry.
There are many of us who are reading (and re-reading) this thread with great interest. The discussion and information about synergistically combining difference regulator methods has opened an entirely new avenue of thought on circuit design for me. While I'd love to openly participate in the discussions, I need to study these ideas much more thoroughly before I might contribute in any meaningful way. I suspect many others like me are paying close attention, but keeping silent unless (until?) we have something of value to add.
Mr. Curl, thanks for suffering the slings and arrows long enough for the intelligent discussion to start. You have seeded and catalyzed something very worthwhile here. While I would dearly love to study the schematics for the blowtorch, if I were in your shoes I wouldn't be sharing publically now or anytime soon either. I do hope that you continue to drop the occasional crumb for us to follow.
On behalf of the multitude of lurkers ... Thanks
Terry
P.S.: Personally, I think the wiring arrangement in the Blowtorch is quite elegant, and well presents the craftsmanship that is involved. To me it communicates that there aren't any compromises being made to make it mass-manufacturable.
There are many of us who are reading (and re-reading) this thread with great interest. The discussion and information about synergistically combining difference regulator methods has opened an entirely new avenue of thought on circuit design for me. While I'd love to openly participate in the discussions, I need to study these ideas much more thoroughly before I might contribute in any meaningful way. I suspect many others like me are paying close attention, but keeping silent unless (until?) we have something of value to add.
Mr. Curl, thanks for suffering the slings and arrows long enough for the intelligent discussion to start. You have seeded and catalyzed something very worthwhile here. While I would dearly love to study the schematics for the blowtorch, if I were in your shoes I wouldn't be sharing publically now or anytime soon either. I do hope that you continue to drop the occasional crumb for us to follow.
On behalf of the multitude of lurkers ... Thanks
Terry
P.S.: Personally, I think the wiring arrangement in the Blowtorch is quite elegant, and well presents the craftsmanship that is involved. To me it communicates that there aren't any compromises being made to make it mass-manufacturable.
Richard,
I have been mulling over your schematic (post 180) which I find most interesting for my future project and have some question about it.
Why do you use a BJT for the pass transistor instead of a MOSFET? I guess there must be some advantage that eludes my understanding, could you elaborate over this?
Which would be your commercial pick for the JFET shown on the schematic?
Have you tested this circuit, part or all of it?
Thanks you for these wonderful ideas on PSu’s
I have been mulling over your schematic (post 180) which I find most interesting for my future project and have some question about it.
Why do you use a BJT for the pass transistor instead of a MOSFET? I guess there must be some advantage that eludes my understanding, could you elaborate over this?
Which would be your commercial pick for the JFET shown on the schematic?
Have you tested this circuit, part or all of it?
Thanks you for these wonderful ideas on PSu’s
apassgear said:Richard,
I have been mulling over your schematic (post 180) which I find most interesting for my future project and have some question about it.
Why do you use a BJT for the pass transistor instead of a MOSFET? I guess there must be some advantage that eludes my understanding, could you elaborate over this?
Thanks you for these wonderful ideas on PSu’s
You can use a BJT pass element, or shunt element, you just have
to account for 2 things.
1) Base current which may/may not affect the base voltage and
drift.
2) Base current noise, which will mean a reasonably low impedance
is needed at this point.
Otherwise BJT's will work fine and result in a lower OP Z (if that
is the objective).
Cheers,
Terry
john curl -
No, folks, the preamp design will not be released in the DIY domain. Sorry, but I am still building them.
---------------------------------------------------------
Mr Curl i respect that, however do you have some other preamps
of yours you would like to share with our members here
thanks
No, folks, the preamp design will not be released in the DIY domain. Sorry, but I am still building them.
---------------------------------------------------------
Mr Curl i respect that, however do you have some other preamps
of yours you would like to share with our members here
thanks
Actually, Mastertech, I have made a number of preamp designs over the years, but there are problems with DIY implementation. Of course, I published the Levinson JC-2 preamp almost 30 years ago. After that, I designed the JC-80, the Lineage preamp, the Vendetta preamp prototype, and a whole line of Parasound preamps, including the 1100, 1500 and 2000. Now there is the CTC and the Parasound JC-2 preamp, both still in production.
Most of the Parasound stuff is pretty good, but difficult to implement, because each preamp has so many features, and this makes it complicated.
The JC-80 would be a good candidate, but the output fets are not available to anyone, anymore. In fact, most of my best designs use difficult to find or obsolete fet's. It seems that only Erno Borbely and I have any stock of these fets and Erno sells them to audiophiles at a high price. I would too, if I were to sell any.
This poses a bit of a dilemma. If I publish specific circuits, then I will be asked by audiophiles around the world to 'help' them find parts, etc. This creates an almost impossible situation, so I would prefer not to do it. I hope that this explains my reluctance to publish my circuits, especially on a DIY website.
Most of the Parasound stuff is pretty good, but difficult to implement, because each preamp has so many features, and this makes it complicated.
The JC-80 would be a good candidate, but the output fets are not available to anyone, anymore. In fact, most of my best designs use difficult to find or obsolete fet's. It seems that only Erno Borbely and I have any stock of these fets and Erno sells them to audiophiles at a high price. I would too, if I were to sell any.
This poses a bit of a dilemma. If I publish specific circuits, then I will be asked by audiophiles around the world to 'help' them find parts, etc. This creates an almost impossible situation, so I would prefer not to do it. I hope that this explains my reluctance to publish my circuits, especially on a DIY website.
Mr. Curl,
You now know it, I am one of your great fans and this since a long time.
I have schematics of PLD1100, PLD1500 and PLD-2000 Parasound preamplifiers, the schematic of Vendetta SCP-2B and the schematic of the line stage of Dennesen JC-80.
I understand very well your reticence to publish your designs.
PassLabs has just stopped lately, the publication of service manuals of this products no longer in production by reason of the manufacture of clones in Asia destined to the sale.
But, I assure you that if you want well to send me by private email the schematic of the Blowtorch, I engage me to not to importune you for to get the different parts. LOL, LOL.
Naturally as I already specified him in my post #1 of this thread in a strictly personal purpose and no commercial.
Make us dream again a long time with your concepts.
Darry
You now know it, I am one of your great fans and this since a long time.
I have schematics of PLD1100, PLD1500 and PLD-2000 Parasound preamplifiers, the schematic of Vendetta SCP-2B and the schematic of the line stage of Dennesen JC-80.
I understand very well your reticence to publish your designs.
PassLabs has just stopped lately, the publication of service manuals of this products no longer in production by reason of the manufacture of clones in Asia destined to the sale.
But, I assure you that if you want well to send me by private email the schematic of the Blowtorch, I engage me to not to importune you for to get the different parts. LOL, LOL.
Naturally as I already specified him in my post #1 of this thread in a strictly personal purpose and no commercial.
Make us dream again a long time with your concepts.
Darry
john curl said:
Check also at Ampslab for low prices:
http://www.ampslab.com/components_fets.htm
The service is excellent!
Of course, the most difficult part is to have matched jfets. Erno Borbely can provide matched parts but the price is even higher. However, it you need only a few fets to build a super preamp or driver of power amp, the price for these fets compared to other parst to build a complete equipment is still low in comparision in my opinion.
Fab
I guess that John is refering to 2SJ72 and 2SK147 (both V type ?)... Toshiba developped them for its own AUREX range... The brand no longer exists, and this parts are no more in production.... But the stock lasted for a while !
And NO, Erno Borbely has no longer any of them, and his current claim that he still have some stock to sell is absolutely wrong... I said him a couple times, but it seems that at moments he just forget to delete them from his current parts price list, again and again... I just know that because... Erno unmounted parts (V type) from some of his early prototypes to send them to me...
And for other John's schematics, some parts are really lacking. So, cloning is not possible for most of his previous designs.
No more special TN and TP0606N5 around, nor 2SJ75 and 2SK240, nor original J110... Sadly enough ! Some of these parts had very good specs at the time and still are amongst the best ones I used. And I spared some of these good vintage Japanese parts all along with US Motorola MPSU series and some others...
IMO and nowadays, similar Japanese parts are no better that old fashioned ones, but they are mostly monolithic duals in lieu of separate parts... Hence far better matching, and far easier to match...
But Darry is right that great topologies from John and others and some local experiments lead to great results with little parts cost... It's a pity that some Taïwanese just commercially copy original but no more in production Nelson stuff ! Legally, it is no counterfeiting... But those guys din't rob only schematics but prevented some thousands to discuss them for a while... So, IMO, they are only morrons !
Jbaudiophile
And NO, Erno Borbely has no longer any of them, and his current claim that he still have some stock to sell is absolutely wrong... I said him a couple times, but it seems that at moments he just forget to delete them from his current parts price list, again and again... I just know that because... Erno unmounted parts (V type) from some of his early prototypes to send them to me...
And for other John's schematics, some parts are really lacking. So, cloning is not possible for most of his previous designs.
No more special TN and TP0606N5 around, nor 2SJ75 and 2SK240, nor original J110... Sadly enough ! Some of these parts had very good specs at the time and still are amongst the best ones I used. And I spared some of these good vintage Japanese parts all along with US Motorola MPSU series and some others...
IMO and nowadays, similar Japanese parts are no better that old fashioned ones, but they are mostly monolithic duals in lieu of separate parts... Hence far better matching, and far easier to match...
But Darry is right that great topologies from John and others and some local experiments lead to great results with little parts cost... It's a pity that some Taïwanese just commercially copy original but no more in production Nelson stuff ! Legally, it is no counterfeiting... But those guys din't rob only schematics but prevented some thousands to discuss them for a while... So, IMO, they are only morrons !
Jbaudiophile
I worked a little more on the PSU that I proposed a few posts preceding; the schematic is a little bit different.
I built it in a prototype form:
Vout is +15V /-15V, Zout around 2 Ohms, input noise rejection about 70/80 dB until 1.5 MHz beyond my measures are not very significant as you could see on the photos.
I don’t use the common mode choke yet.
Noise is 6uV in the range of 10 Hz. - 300 kHz.
Load Regulation is 0.05 % in the range 0-150 mA.
Regulators uses Fred Dieckmann circuit to improve noise and PSRR.
Some measures could be not very significant taking into account the wiring…
As you can see…
PSU_Test1
PSU_Board
Apassgear:
For the power current sources I prefer BJT’s over Mosfet’s’, bias is simpler and less noisy in this case, parasitic capacitances are also lower, for the shunt elements I prefer Mosfets, lower gate currents and higher “channel” separation and drift, higher capacitances are not important at this place, but I can be wrong. I would carry out complementary tests later, maybe with other devices, at the moment I am quite busy in my job.
Jfet’s are 2SK170, 2SJ74, current sources are mostly devices like J508 to J511.
The problem for some fets and current sources could be the Vcc max around 25V for some of them in the case of Vout upper to +/-20V Medium power BJT’s are 2SA968/2SC2238, because I have them on hand, probably more recent and more powerful devices would be better.
Mosfets are 2SJ334/ IRL9Z34 and IRLIZ44 also because I have them since some work on cap multipliers and followers, I guess that IRF530/9530 could be o.k as they are easier to get.
I built it in a prototype form:
Vout is +15V /-15V, Zout around 2 Ohms, input noise rejection about 70/80 dB until 1.5 MHz beyond my measures are not very significant as you could see on the photos.
I don’t use the common mode choke yet.
Noise is 6uV in the range of 10 Hz. - 300 kHz.
Load Regulation is 0.05 % in the range 0-150 mA.
Regulators uses Fred Dieckmann circuit to improve noise and PSRR.
Some measures could be not very significant taking into account the wiring…
As you can see…
PSU_Test1
PSU_Board
Apassgear:
For the power current sources I prefer BJT’s over Mosfet’s’, bias is simpler and less noisy in this case, parasitic capacitances are also lower, for the shunt elements I prefer Mosfets, lower gate currents and higher “channel” separation and drift, higher capacitances are not important at this place, but I can be wrong. I would carry out complementary tests later, maybe with other devices, at the moment I am quite busy in my job.
Jfet’s are 2SK170, 2SJ74, current sources are mostly devices like J508 to J511.
The problem for some fets and current sources could be the Vcc max around 25V for some of them in the case of Vout upper to +/-20V Medium power BJT’s are 2SA968/2SC2238, because I have them on hand, probably more recent and more powerful devices would be better.
Mosfets are 2SJ334/ IRL9Z34 and IRLIZ44 also because I have them since some work on cap multipliers and followers, I guess that IRF530/9530 could be o.k as they are easier to get.
A few simple answers to earlier questions:
The Vendetta preamp now has C, D, and T mods, since B.
It is now almost impossible to get Toshiba fets in matched pair. I have used k240, K146, k389, and their complements in most of my designs. To specify these now would be a problem.
Many of my less expensive designs use relays. Relays are OK, but silver on silver switches are better.
You have to ask Bear about the teflon silver cable that we use in the CTC. It is VERY expensive.
The Vendetta preamp now has C, D, and T mods, since B.
It is now almost impossible to get Toshiba fets in matched pair. I have used k240, K146, k389, and their complements in most of my designs. To specify these now would be a problem.
Many of my less expensive designs use relays. Relays are OK, but silver on silver switches are better.
You have to ask Bear about the teflon silver cable that we use in the CTC. It is VERY expensive.
John,
actually, I didn't expect you to bring up the contact material thing if else I didn't got you wrong here, is that the main issue to not chose relays.. well, I'm not a relay expert but imagine relays can be obtained with any kind of contact material and fashions, I thought you would answer something else, what's your take?
Cheers Michael
actually, I didn't expect you to bring up the contact material thing if else I didn't got you wrong here, is that the main issue to not chose relays.. well, I'm not a relay expert but imagine relays can be obtained with any kind of contact material and fashions, I thought you would answer something else, what's your take?
Cheers Michael
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