John Curl's Blowtorch preamplifier

[PMA]

I may show photos of casework parts milled from thick alluminium later.

http://www.diyaudio.com/forums/showthread.php?postid=1268409#post1268409

A little bit late, but here it is:

 

[jbaudiophile]

Hi, Jacco,

No, you are right... He even had the tantalum unobtainium trimpots exchanged for cermet ones...

Here is a difference between a tech and an engineer. John Curl had the Hell to have his designs stable (without any oscillation) with NO unwanted capacitor added in the signal path. A long crusade from the JC-2 to the Blowtorch that has NO cap in the signal path. I now know what he calls "elegant" design. A straight line from his very earlier works.

A tech would just have sticked a cap or two to tame oscillations ... Et voilà... What was the problem ?? Just fixed soon !

But as I read earlier, I am quite boring people with such stories, eh ? And moderators surely more, as they must read...

So, I will leave the forum tomorrow. Just better leaving than to be banned...

Will glance at intervals on Blowtorch thread progress... Anyway, I will re-draw the Dennesen servo. Somewhat more complex that the Vendetta one (sorry for, Dimitri ! Really). But really simple in Blowtorch's one regard... But will be only posted tomorrow.

Jbaudiophile

 

[QSerraTico_Tico]

I still don't get the RelCap MKP to Roederstein MKT1813 Polyester exchange in the SCP-1 on those pics.
Am i missing something or is Mr Amp8 a witty git who swaps anything yellow for yellow?

Hi Jacco, I made that mistake too once.
Took poly caps from an electronic organ on the street ready to be scrapped.
Woow nice compact caps I thought. Turned out to be mylars...
Now I am sitting on tons of polypropylenes.....

 

[aparatusonitus]

Anyway, I will re-draw the Dennesen servo. Somewhat more complex that the Vendetta one (sorry for, Dimitri ! Really). But really simple in Blowtorch's one regard... But will be only posted tomorrow.

Jbaudiophile

For the reference see http://www.diyaudio.com/forums/showthread.php?postid=834610#post834610

 

[Blues]

http://www.diyaudio.com/forums/showthread.php?postid=1268409#post1268409

A little bit late, but here it is:

Hi Pavel,

Very nice! What's in the smaller box? Looks like a very complex circuit.

I'm thinking the aluminum boxes are milled from castings and not from solid Al like the Blowtorch and the Ayre's latest amp.

 

[carlmart]

I'm thinking the aluminum boxes are milled from castings and not from solid Al like the Blowtorch and the Ayre's latest amp.

I'd say the inner box looks like cast aluminum. The outside box might have been milled from solid Al, as far as we can say from a picture.

 

[PMA]

What's in the smaller box? Looks like a very complex circuit.

I'm thinking the aluminum boxes are milled from castings and not from solid Al like the Blowtorch and the Ayre's latest amp.

There is an A/D transient recorder, sample rate up to 10MHz, 4MB RAM, and optical fibre output. The small box is an industrial one, the big one is custom-made, milled from Al sheets 8mm (I made drawings).

 

[dimitri]

I will re-draw the Dennesen servo

 

[john curl]

You have done me great service in this website, JBaudiophile. Don't let the moderators bring you down.

 

[Variac]

I don't see that JB has done anything wrong recently
If we were in fact bored, which I haven't been, well that's a job hazard!

Variac

 

[dimitri]

You have done me great service in this website, JBaudiophile. Don't let the moderators bring you down.

 

[courage]

john Curl: You have done me great service in this website, JBaudiophile. Don't let the moderators bring you down.

John, if you let others do the work of reverse engineering your lost schematics, be a gentlemen and at least point out the errors you see. Not for my sake, but for those who took the time and made the effort.

Be a good sports!

 

[john curl]

Please lighten up, Dimitri. I will get around to it, BUT I have no way of posting schematics, myself. Why is it that you don't talk to me on the phone any more? We could resolve this more quickly.

 

[anatech]

Hi Jbaudiophile,

So, I will leave the forum tomorrow. Just better leaving than to be banned...

We have talked off line (by email) a little. I see no reason for you to leave. You aren't boring us.

Have you noticed your posts appear quickly?

Hi John,

Don't let the moderators bring you down.

Huh?
You lost me there. PM might be appropriate if you have any questions. I'll have to leave soon, but I'll be back later and I will answer your questions to the best of my ability.

-Chris

 

[Nelson Pass]

Please lighten up, Dimitri. I will get around to it, BUT I have no way of posting schematics, myself.

I feel certain that your schematics would be of sufficient interest
that somebody, perhaps administration, would make some
arrangements for you to post them.



Maybe you could use your Windows (tm) PC

 

[SY]

John, if you email me the schematics, I'll be happy to post them for you.

 

[GRollins]

Um, not to belabor the obvious, but it seems to me that if John had them in a format wherein they could be e-mailed, then he could just as easily post them. I suspect it's the hardcopy to electronic transition that's the problem.
Yes, he could enter them into a CAD/simulation program, but that might be a nuisance.

Grey

 

[SY]

If that's the case, I'll cart my scanner over there and do the dirty deed.

Actually, attaching files (if they're not of a certain size and format) can be tricky for the computer-challenged, and I think John will acknowledge that this describes him.

 

[GRollins]

John,
If it's a case of trying to meet the requirements of image posting here you have my deepest sympathy. Many is the time that I've cursed the restrictions on images here. Getting a schematic posted within the size limits, yet clear enough to read easily, can be a nightmare.

Grey

 

[anatech]

Hi Grey,

Getting a schematic posted within the size limits, yet clear enough to read easily, can be a nightmare.

Tell me about it!

If the schematics were hosted off site you could simply link to them. You can then have high resolution.

-Chris