Hello, Carlos,
Not so easy, and rather a long story...
John has been defrauded a long time... By Mark Levinson first IMO (then we all got JC-2 and JC-3 schemes from John for free, and I just think that we all (or almost all of us) saw them and had a start desi.gn from it... As a classic design as the Pass A40 !
He worked as a consulting engineer a lot of time (Alembic, Dennesen, Symmetry, Gale, SOTA,...) throughout the world. Then founded Vendetta Research that just ONE journalist word ruined in a snap... But John is starting it again (just have a look on the nearly newcoming Vendetta Research VR3)! Would just be an honour here to have a not so blurred pic on the Forum, eh???
And then, he lost a lot of valuable parts and schemes in an Oakland fire in 1991. So, probably he lost a lot of them (all ?), and just can't redraw them but from memory. I understood it soon, and I am STILL returning past reverse-engineered schemes to their Dad...
And he reported too to have at least 2 separate examples of his designs "borrowed" commercially with no royalties given to him. The last thing I came aware of is just that his PATENTED design was just used by Bruel & Kjaer as it there was no copyright infringement !!! (eh, what does the police ????). He also told us that some only discussed ideas from him just turned to be on the patent roads from "colleagues"... I am mostly a lawyer and some forumers still know what I means about such "borrowings"...
And I suspect that the list is still longer... He is a professional and makes his livings from... as some others...
But I agree with you that the more not published schemes we can gather around John, the more he is earning an audio legend status. perhaps that he would accept to complete what schemes are missing him...
All the best, Carlos,
Jbaudiophile
Not so easy, and rather a long story...
John has been defrauded a long time... By Mark Levinson first IMO (then we all got JC-2 and JC-3 schemes from John for free, and I just think that we all (or almost all of us) saw them and had a start desi.gn from it... As a classic design as the Pass A40 !
He worked as a consulting engineer a lot of time (Alembic, Dennesen, Symmetry, Gale, SOTA,...) throughout the world. Then founded Vendetta Research that just ONE journalist word ruined in a snap... But John is starting it again (just have a look on the nearly newcoming Vendetta Research VR3)! Would just be an honour here to have a not so blurred pic on the Forum, eh???
And then, he lost a lot of valuable parts and schemes in an Oakland fire in 1991. So, probably he lost a lot of them (all ?), and just can't redraw them but from memory. I understood it soon, and I am STILL returning past reverse-engineered schemes to their Dad...
And he reported too to have at least 2 separate examples of his designs "borrowed" commercially with no royalties given to him. The last thing I came aware of is just that his PATENTED design was just used by Bruel & Kjaer as it there was no copyright infringement !!! (eh, what does the police ????). He also told us that some only discussed ideas from him just turned to be on the patent roads from "colleagues"... I am mostly a lawyer and some forumers still know what I means about such "borrowings"...
And I suspect that the list is still longer... He is a professional and makes his livings from... as some others...
But I agree with you that the more not published schemes we can gather around John, the more he is earning an audio legend status. perhaps that he would accept to complete what schemes are missing him...
All the best, Carlos,
Jbaudiophile
Dennesen JC-80
You asked for them, John... Here they are... 😀
Sorry for the bad quality (as I know that some other guys have better ones...). But clear enough to have a discussion about the whole topology... But without any guarantee that they are 100% accurate... Just worked fine for a Singapore pal repair...
As an evidence, quite a Blowtorch cousin...
All the best, all,
Jbaudiophile😀
You asked for them, John... Here they are... 😀
Sorry for the bad quality (as I know that some other guys have better ones...). But clear enough to have a discussion about the whole topology... But without any guarantee that they are 100% accurate... Just worked fine for a Singapore pal repair...
As an evidence, quite a Blowtorch cousin...
All the best, all,
Jbaudiophile😀
Bad Dennesen JC-80 scheme
Hi, all,
Yeah... I know... Just having a competition with John about blurring pics... Won a prize ???
Jbaudiophile.
Hi, all,
Yeah... I know... Just having a competition with John about blurring pics... Won a prize ???
Jbaudiophile.
First of all, John, I want to apologize. I didn't know the BT was an on-going project.
I do respect and admire your attitude toward us. Just by being here shows the unusual type of person you are. And I'm sorry to have been the one who had you feel as uncomfortable as to write some bitter words asking why we want schematics or what you certainly don't owe us.
Perhaps I may risk an answer to your questions. I don't think there's any malice on our curiosity. The perfect sound seems to be a holy grail for us all, and how to get there is what we look for.
It's interesting to note that in spite of people knowing that the "book" was sealed, forum people insisted on walking around it, generating new ideas and re-thinking everything in order to build something like the BT.
Don't you think that's quite an honor and not something to complain about?
Carlos
I do respect and admire your attitude toward us. Just by being here shows the unusual type of person you are. And I'm sorry to have been the one who had you feel as uncomfortable as to write some bitter words asking why we want schematics or what you certainly don't owe us.
Perhaps I may risk an answer to your questions. I don't think there's any malice on our curiosity. The perfect sound seems to be a holy grail for us all, and how to get there is what we look for.
It's interesting to note that in spite of people knowing that the "book" was sealed, forum people insisted on walking around it, generating new ideas and re-thinking everything in order to build something like the BT.
Don't you think that's quite an honor and not something to complain about?
Carlos
JB the schematic is OK, a few errors. Good starting point. Anyone do the servos?
I have no idea what LOIS is.
I have no idea what LOIS is.
John,
Since jbaudiophile has taken the time to draw and post the schematic, would you be so kind to also point out the errors you see?
Thanks in advance ;-)
Since jbaudiophile has taken the time to draw and post the schematic, would you be so kind to also point out the errors you see?
Thanks in advance ;-)
they can be reverse engineered from these hi-res pics 😀
http://amp8.com/tr-amp/foreign/etc/scp-2a.htm
Dennesen reverse engineering scheme
Hello, John,
As you named Clark (only Clark Kent, aka Superman...) is known to me... I supposed that Badge was with Lois (Lane...)...
About the Dennesen, was a truly "love" affair with, as I dissuaded a Singapore guy (now a friend) to sell this incredible preamp to a Japanese collector ONLY. The preamp had Iintermittent problems, and after much time put on the reverse-engineering, no problem was found on the PCB (that was quite worst amateur solder salvaged underside, with flying straps...).
BUT checking cables turned to encounter an INCREDIBLE flaw in the PSU : the BIG Xformer (yes, the Costwold toroïdal!) was gone... And guys, if I succeed to have the pic downsized to fit the 102400 Bytes allowed, you will know what a serious preamp PSU was 20 years ago for John ! My very first amp had no such one !
And maybe that some errors crept (2490 ohms instead of 2790 that doesn't exist...). But the overall topology seems OK... Now perhaps that I can persuade a certain person to release the offset correction side. The Dennesen was quite complex to reverse because of the tracks lengths ! And with no scheme, no hope to repair. The scheme can seem to be quite simple, guys, but to reverse it was another story !
Jbaudiophile
Hello, John,
As you named Clark (only Clark Kent, aka Superman...) is known to me... I supposed that Badge was with Lois (Lane...)...
About the Dennesen, was a truly "love" affair with, as I dissuaded a Singapore guy (now a friend) to sell this incredible preamp to a Japanese collector ONLY. The preamp had Iintermittent problems, and after much time put on the reverse-engineering, no problem was found on the PCB (that was quite worst amateur solder salvaged underside, with flying straps...).
BUT checking cables turned to encounter an INCREDIBLE flaw in the PSU : the BIG Xformer (yes, the Costwold toroïdal!) was gone... And guys, if I succeed to have the pic downsized to fit the 102400 Bytes allowed, you will know what a serious preamp PSU was 20 years ago for John ! My very first amp had no such one !
And maybe that some errors crept (2490 ohms instead of 2790 that doesn't exist...). But the overall topology seems OK... Now perhaps that I can persuade a certain person to release the offset correction side. The Dennesen was quite complex to reverse because of the tracks lengths ! And with no scheme, no hope to repair. The scheme can seem to be quite simple, guys, but to reverse it was another story !
Jbaudiophile
Dimitri,
The pointed site has only Vendetta pics, no Dennesen ones... And I know little people that have a Dennesen or internal pics... 😀
And I mostly agree with Analog_Sa (thanks for your reverse efforts on the Vendetta !)... The Vendetta PCB is just a rude piece to reverse by itself ! Just try to determine what each copper plane is and what it does is quite time consuming... I know it, as I tried to reverse it too !
As an evidence for me, the Vendetta phono PCB was a "multi-purpose" one (SCP-1, then SCP-2), and perhaps too a part of the Vendetta Preamp John spoke about ONCE (in a relay sonic qualities thread), but didn't appear on the market. No details about this one, nor pic, nor scheme... and no reverse job to do too...
Jbaudiophile
The pointed site has only Vendetta pics, no Dennesen ones... And I know little people that have a Dennesen or internal pics... 😀
And I mostly agree with Analog_Sa (thanks for your reverse efforts on the Vendetta !)... The Vendetta PCB is just a rude piece to reverse by itself ! Just try to determine what each copper plane is and what it does is quite time consuming... I know it, as I tried to reverse it too !
As an evidence for me, the Vendetta phono PCB was a "multi-purpose" one (SCP-1, then SCP-2), and perhaps too a part of the Vendetta Preamp John spoke about ONCE (in a relay sonic qualities thread), but didn't appear on the market. No details about this one, nor pic, nor scheme... and no reverse job to do too...
Jbaudiophile
At this point it might be worthwhile to talk about the concepts in John's mind when he designed these products. Low noise is very obvious.
At some point we should be moving forward unless John would like to conduct a lesson in history. That would be entirely up to John.
-Chris
At some point we should be moving forward unless John would like to conduct a lesson in history. That would be entirely up to John.
-Chris
I've pulled some posts with some personal insults. Let's keep it above the belt.
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