John Curl's Blowtorch preamplifier part II

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diyAudio Member RIP
Joined 2005
A PR enthousiast could have changed it in anticipation.

(From-the-Bridge sounds a lot more exclusive in French. From Mil (shite village in the south) to DeMille seems to work for selling movies. Ver.. to Van-der.. is bound to end in bankruptcy though)
And don't forget that the eminent noise theorist Aldert Van der Ziel (don't call him Aldi) was a passionate theologian. Whether he went bankrupt financially, let alone philosophically, I couldn't say.

I continue to be amazed when searching for his engineering books, easy to do with that fairly rare name, his non-engineering works appear.

Once I got a deal on his "Noise" because the bookseller listing it spelled the name Van der Zeil, and I thought such an error might have been made, so searched under the misspelling.
 
diyAudio Member RIP
Joined 2005
Every encouragement - it is an interesting and worthwhile journey IME.
I've been working on and off on phono pre stuff for about 15 years now. I've come close to deciding on an approach, only to have a new Gedankenblitz. Most recently someone approached me who wanted a preamp along some venerable lines and figured he liked a THAT Corp. IC, and liked a passive interstage LCR network for RIAA. I had supposed that he wanted both MC and MM, and for MM the part he had in mind is not suitable.

I probably should have accepted those criteria although there was negligible design work. But I don't find that sort of thing very interesting. However I was forced to reconsider use of at least one inductor, and it led to something that got me interested again.

I did manage, for a friend, to do an MC stepup, with three paralleled SK170 equivalents and a Boxall pair as the folded cascode, and even managed to build one. No global feedback, some curvature cancellation by fine-tuning the pull-up resistor value for the cascode. That was also to cater to the friend's penchant for avoiding GNF (a prejudice that I don't really share, but since levels from a typical MC cartridge are small, the distortion is fairly low, and the large input capacitance is shrugged off by the low inductance and resistance of the cartridge). A lot of the work was in the power supplies --- the basic amplifier itself was fairly simple, but as part of that simplicity the PSRR wasn't that hot.

But this friend gets increasingly radicalized in favor of tubes, so he lost interest. I'm using my prototype to play LPs, and it feeds a mid-fi old NAD separate which has an astonishingly small number of transistors. To my ears it sounds fine. Some work still needed on common mode chokes as there is still some sensitivity to mains transients, or maybe it is radiated B fields.
 
The name is familiar, but no. I have a friend who is very fond of such stuff.

Just asked because he worked with JBL and Tascam to make high quality electronics accessible to musicians, which I found interesting.

Guitar and >NO< vocals is one of my eccentric interests. Amazing how 60's folk music without vocals drives a certain crowd nuts.
 
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