John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
€11400 list price/pair, that's what I find in their german brochure.

Inpedendent measurements are hard to find, and Silbersand never publishes anything themselves, looks like a CI thing for them (a pity as they do make really good speakers). Another german maker of similar speakers, Schanks Audio, also uses MFB and Doppler cancellation (this time in the digital domain), their developpers frequent some german forums and share some details occasionally. Like some others they also use current drive on their AMT tweeters, a nice application for current drive with excellent results.
 
I have known people who can play all the right notes in the right order at the right time, as specified in the score, yet somehow no music emerges from the instrument...

I used to tell my kids that's phase 1: it takes years to go through all the mechanical and repetitive parts, doing scales and things, kind of like calculus for the rest of us.

Then you can start to put your guts into it. And it's all right if you have to unlearn, or go beyond some of the stuff you did in phase 1. And of course, because it's no longer carved in stone... err score, some will love it, and some will hate it... OOPS, sorry, now we're in the snake oil turf 🙂
 
I don't understand you there Scott.
I was relating a loudspeaker listening test where PN was the signal, and the reproduced sound changed according to BQP placement against the speaker cable.

The claims are removing noise in preference to the signal, if there is noise in the signal how does it know the difference? I don't quite know why I try to reason through this nonsense anymore.
 
Again, this is mostly nonsense. It was best to throw away the Record-Reproduce electronics of either the Studer or the Ampex and start from scratch. That is what I did 3 times. The Studer transport was significantly better than the earlier Ampex transports, and I just stuck with Studer to make upgrades.

John,

I presume this is the Studer (Mark Levinson) ML-5 modified Studer A80. I
believe Bruce B normally uses a Doshi Preamp which is a hybrid SS / valve
tape preamp.

I don't think it's entirely reasonable to expect this level of electronics in a
(semi) mass produced tape machine of that era.

T
 
Bringing the Grateful Dead’s Wall of Sound Back to Life
By Clive Young.
Tribute act Dead On Live performs meticulously transcribed, note-for-note recreations of legendary shows by the Grateful Dead, but will take that obsession to the next level when it teams with Asbury Audio to recreate the Dead’s legendary Wall of Sound audio system next week.
 
Bringing the Grateful Dead’s Wall of Sound Back to Life
By Clive Young.
Tribute act Dead On Live performs meticulously transcribed, note-for-note recreations of legendary shows by the Grateful Dead, but will take that obsession to the next level when it teams with Asbury Audio to recreate the Dead’s legendary Wall of Sound audio system next week.

Howz this for a recreation? YouTube

A Moog wall of sound
 
Last edited:
For John Curl:

Here's an early experiment on a simple test subject. It's a plain ordinary 100 Watt incandescent lightbulb, made by GE and sold for US applications (115VAC 60 Hz). Test performed in my workshop, with plain ordinary residential AC service, in the SF Bay area. There is quite a "long tail" on the current-vs-time waveform, probably because the bulb takes several seconds to come to thermal equilibrium. But for studying the initial turn-on current, a/k/a/ inrush, this sort of view seems helpful.

If you look really really closely and squint your eyes really hard, you can see the triac "pull in" and "drop out" points. But since a triac is not a relay, they use different terminology that I am too lethargic to look up at the moment.

_
 

Attachments

  • Incandescent_100W_inrush.png
    Incandescent_100W_inrush.png
    35.6 KB · Views: 317
Last edited:
The claims are removing noise in preference to the signal, if there is noise in the signal how does it know the difference? I don't quite know why I try to reason through this nonsense anymore.
In this case the change heard is not in the signal but change in noise mechanisms in the system (amplifier/cable/speaker as a system) it seems.

My link to the synchronising metronomes video is in reference to observations regarding my filtering, and that is that the effect of my filters is not perfectly immediate.
When applying my filtering there is smaller initial step change followed by longer term slope change through to full effect........actually quite like the metronome example of phase locking.
The PN/BQP/speaker cable experiment showed similar time dependency.

Dan.
 
Status
Not open for further replies.