john curl said:Lead? We can't use no stinkin lead!
The lead is not metallic, it's part of the crystal. The conductive work would be done by the ITO- for the case, presumably, you're interested in screening out noise and keeping things acoustically and vibrationally quiet? It's not like the case carries a lot of current. If there is a sonic advantage to the billet technique you used, I'll bet it was how little the components and boards moved around. Whaddaya think?
Am I to understand that a high OL design as the Blowtorch necessitates the use of such a case, with the associated high cost ?
That would imply that the crude hardware investment becomes the dominant factor in that league, not the fancy parts and labor.
(fwiw: compared to some other pre models, the BT didn't seem that expensive. It surprises me that a buck can be made from manufacturing only 40 or 50 of them.)
To read that even an eloquent gent like JBA does not escape the axe is yet another eyebrow raiser.
The motivation for moderating distinguished members still escapes me, individuals such as Charles Hansen and John Curl should have earned themselves decades of credit.
Occasionally it looks as that the mass overhere is supposed to be enlightened solely by reading eternal replay ads by arrogant one-liner posters and Master idiots from Oz.
Praise be that CH, JC and JBA still haven't thrown in the towel.
That would imply that the crude hardware investment becomes the dominant factor in that league, not the fancy parts and labor.
(fwiw: compared to some other pre models, the BT didn't seem that expensive. It surprises me that a buck can be made from manufacturing only 40 or 50 of them.)
To read that even an eloquent gent like JBA does not escape the axe is yet another eyebrow raiser.
The motivation for moderating distinguished members still escapes me, individuals such as Charles Hansen and John Curl should have earned themselves decades of credit.
Occasionally it looks as that the mass overhere is supposed to be enlightened solely by reading eternal replay ads by arrogant one-liner posters and Master idiots from Oz.
Praise be that CH, JC and JBA still haven't thrown in the towel.
jacco vermeulen said:
Hi Jacco,
could you please kindly explain what you mean as "high OL design" - high Open Loop GAIN design or just HIGH END Open Loop design.
Thanks,
Pavel
Pavel,
I am surprised that one so sharp as you fails to apprehend Jacco's clear meaning....
Unless, of course, you are being obtuse and taking a swipe at the Blowtorch, I suppose that's on the cards....
I thought Elecon's words almost lyrical. Take a bow, John.
Ciao,
Hugh
I am surprised that one so sharp as you fails to apprehend Jacco's clear meaning....
Unless, of course, you are being obtuse and taking a swipe at the Blowtorch, I suppose that's on the cards....
I thought Elecon's words almost lyrical. Take a bow, John.
Ciao,
Hugh
Pavel,
the first 50 posts of this thread should describe what i meant with high OL.
No disrespect meant to any active diyA member, not for terminated ones either.
the first 50 posts of this thread should describe what i meant with high OL.
No disrespect meant to any active diyA member, not for terminated ones either.
What are you folks getting at? Is the Blowtorch too expensive to make? Yes, it is. Could the case be made cheaper with a cheaper look as well? Yes, and it might work almost as well. Still, the people who buy preamps in this range of performance, do not like cheaply made cases. That is why we have to make expensive ones, even if they dominate the overall cost of the unit. Unfortunate, but true.
Hi John,
I do firmly believe you could make a less expensive case that performed as well and possibly looked better. That is up to your tastes and imagination.
If you wished to continue these products, you could. The exact same way they have been done in the past. You could modify the case and produce them at the same cost, more cost or less. You are free to do all these things. I have not, for the record, criticized the selling price - ever.
I don't know if my question annoyed you. I am guessing it has from the lack of an answer. So I'll apologize as this was not my intent. I was hoping you would continue this preamplifier in some fashion.
-Chris
Actually, I don't think anyone has suggested that. I do believe you may have interpreted some comments this way.
I do firmly believe you could make a less expensive case that performed as well and possibly looked better. That is up to your tastes and imagination.
If you wished to continue these products, you could. The exact same way they have been done in the past. You could modify the case and produce them at the same cost, more cost or less. You are free to do all these things. I have not, for the record, criticized the selling price - ever.
I don't know if my question annoyed you. I am guessing it has from the lack of an answer. So I'll apologize as this was not my intent. I was hoping you would continue this preamplifier in some fashion.
-Chris
I don't do metal sculpture for a living and I have little interest in it. It is simply a necessary part of the whole.
Hi Jacco,
Looks very nice!
I am looking to build a preamplifier to replace one with ailing switches. No bankroll so my search continues.
-Chris
Looks very nice!
I am looking to build a preamplifier to replace one with ailing switches. No bankroll so my search continues.
-Chris
True, John,
When you told us that you needed "at least +/- 36 V at 500 mA", from a 56VA split-bobbin Xformer, I thought that it would be easy to find one... Yes, ! And I found some Xformer... But NONE over 2x18V...
Then the RURD460 (To-251) went off the market, and their closest cousins too... Even the 2SJ109/2SK389 are now obsoleting... Hard also to have Teflon boards CNC engraved... Not to speak from the parts that are on the Line amplifier that you surely spared after the '91 Oakland fire where your home and lots of parts and stuff just burnt. But not all of them.
I just imagine the BLOWTORCH experiment as a mix of both mixed experiences (CTC), complimentary skills (CTC), music knowing (as the musician you are), and still more, a deep knowledge of what works with old parts and what doesn't with up-to-date ones. And still a source of inspiration and trying. Some efforts around (just working with a 56VA Xformer to get the right voltages ! LOL !).
All the best, John,
All the best, all,
When you told us that you needed "at least +/- 36 V at 500 mA", from a 56VA split-bobbin Xformer, I thought that it would be easy to find one... Yes, ! And I found some Xformer... But NONE over 2x18V...
Then the RURD460 (To-251) went off the market, and their closest cousins too... Even the 2SJ109/2SK389 are now obsoleting... Hard also to have Teflon boards CNC engraved... Not to speak from the parts that are on the Line amplifier that you surely spared after the '91 Oakland fire where your home and lots of parts and stuff just burnt. But not all of them.
I just imagine the BLOWTORCH experiment as a mix of both mixed experiences (CTC), complimentary skills (CTC), music knowing (as the musician you are), and still more, a deep knowledge of what works with old parts and what doesn't with up-to-date ones. And still a source of inspiration and trying. Some efforts around (just working with a 56VA Xformer to get the right voltages ! LOL !).
All the best, John,
All the best, all,
jbaudiophile said:
I don't get it. Must it ONLY be a 56VA transformer and no larger, or just a split bobbin?
se
Hi Steve,
I'm sure that there is a fair latitude for choice here.
I like running around +/- 35 VDC, others at +/- 30 or 25 VDC. It's all up to the designer and also depends on the standing currents (how much heat do you want to dissipate?).
-Chris
I'm sure that there is a fair latitude for choice here.
I like running around +/- 35 VDC, others at +/- 30 or 25 VDC. It's all up to the designer and also depends on the standing currents (how much heat do you want to dissipate?).
-Chris
anatech said:
Ah, ok.
In that case, JM Transformer makes split bobbins in 10, 12.6, 16, 20, 24, 28, 32, 36, 40, 48, 56, 68, 80 and 120 volts center tapped in VAs starting at 40 and going up to 750.
PLEASE you all! There are clearly various camps here. Those that feel that the Well Known Names from the audio business should be held to a higher standard than other members because ,well they are examples I guess.
Others seem to think that in order to show respect to these people we should avoid holding them to the same standards as other members- "give them a break, we are lucky to have them here."
This place is called DIYAudio, and the highest level member here is the one that makes stuff him or herself, not the best known person.
BUT I think that the Well Known Names do have to put up with more annoying posts, requests, and comments and critisism then a regular member, and I DO feel that we are lucky to have them. Not surprisingly , they know a lot, and when they interact here, a dialog is created- one of the most powerful ways of discovering new truths. Their behavior has been exemplary lately, even under the extra pressure that they are under.
In my opinion, the only solution is to demand the same respect from all members. This includes a sincere attitude, and not a sour aggressive one, discussion of the topic of the thread, not past slights or offenses, and the "Golden Rule": Attack ideas and statements if you sincerely feel that they are misguided, wrong, need to be better defined or supported, but NOT the person making the statements.
I will delete some of the above posts, because they are Off Topic. This is a thread about a preamplifier, There is another thread about moderating. This thread has gotten off track in the past and it was not pleasant. It won't happen again.
Variac
The best transformer for a CTC Blowtorch 'clone' is: Signal Transformer DST-7-56 available from DigiKey. Could anything be easier than that? Use Motorola high speed soft recovery rectifiers, IF you can't get Harris-Fairchild.
john curl said:
Well, yes. It would be easier if DigiKey um... actually stocked that transformer. 😀
se
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