John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
That's what I ended up using in my current line preamp (6 channel Heretical). Some line filtering, common mode filtering on the secondary end, good grounding practice, and Bob's your uncle.

I bet it sounds great. I have set aside triamping for now but it is a great way to go. The Plitron tube output transformers worked great but I don't have much to compare except old Dynas.
 
Might be a good time to reference this ... http://emcesd.com/pdf/uesd99-w.pdf. This gives a flavour of the sort of thing I find is highly relevant, where some of the 'unknowns' may be lurking ...

From 1999! Gosh NCL were paranoid about this when I did my work experience there in 1983....
Also wearing synthetic fibre based clothing will cause ESD problems, its not really new. Equipment if competently designed will have levels of protection for ESD events, from a screened outer case with low impedance path for the ESD current to dissipate to ground, to ESD protection devices for cable borne signals that enter through such a case.
In your case I suggest you buy a ESD floor covering for your listening area, one of these:
ESD Anti Static - Chairs - Industrial Seating

and a cotton ESD safe lab coat or similar, antistatic matting and anti static shoes are available as well...
As I have said in some areas of electronics an ESD event can cause far more than upsetting someone because a piece of equipment has crashed, so it is a well known and studied phenomena...to the extent that most (if not all) electronics assembly houses make it a dismissible offence if you walk around a production area without the correct clothing and level of ESD protection.
One a circuit is designed, static build up is controlled through design and the fact that working circuitry has grounding paths for static so it does not tend to build up like you imagine.

I would be interested on how oversize PSUs can affect the sound of a pre amp, what does that extra power on standby do? Personally I think a main supply with regulator's and power reservoirs where they are needed would be best for reproducing fast transients, ie near the active devices, then you remove the inductive delay from the power supply. Of course these days there is a lot of info regarding power delivery systems, the ever increasing requirements of high switching digital circuitry has helped push research into power system integrity, and before anyone says digital is irrelevant don't forget its analogue (as many like to remind me on digital threads).🙂
 
Also wearing synthetic fibre based clothing will cause ESD problems, its not really new. Equipment if competently designed will have levels of protection for ESD events, from a screened outer case with low impedance path for the ESD current to dissipate to ground, to ESD protection devices for cable borne signals that enter through such a case.
In your case I suggest you buy a ESD floor covering for your listening area, one of these:
ESD Anti Static - Chairs - Industrial Seating
Whatever you may think of the chances for static or some related behaviour to be an influence, the reality, for me, is that it's something that does have impact - a lot of my frustration in years gone by in trying to achieve optimum sound was not appreciating its contribution. Even my lowly PC monitor speakers are audibly susceptible to this, so I've done some rough and ready fiddling to lessen the factor ...

Edit: just to repeat, the real benefit of taking these sort of measures is that low level clarity improves. Which means, the volume can be raised to much higher levels without one being irritated by unpleasant, musically unrelated 'noise' artifacts intruding into one's awareness ...
 
Last edited:
Some empirical data and illustration about what you think is happening may help, as obviously on mission critical/life critical designs you don't want static causing any problems. Also in active electronics with a defined discharge path (the GND, Ground, 0V return path whatever you wanna call it) static has a path to go down so generally wont build up....
 
The preamp sounds like nothing (other than its removal of noise from the satellite TV system). I'm one of those old-fashioned sorts who want a preamp to raise and lower the volume and do nothing else.

The conveyance of musical emotion is the job of the performer, not the reproduction electronics. 😀

+1:up:

It always worry's me when I sea the term "voiced" or "voicing" used in relationship to audio electronics, voicing is what Luther's and such like do to instruments not audio reproduction equipment.
 
Some empirical data and illustration about what you think is happening may help, as obviously on mission critical/life critical designs you don't want static causing any problems. Also in active electronics with a defined discharge path (the GND, Ground, 0V return path whatever you wanna call it) static has a path to go down so generally wont build up....
I've already said that this is one area where I don't have simple answers as to "what's going on". One needs instrumentation with the right sensitivities to try and pick up anomalies - one reason why I mentioned that link. I have subjectively found this to be a far greater problem with digital, vs. analogue playback - a simple explanation could revolve around static levels very rapidly building up and disipating, at relatively low voltage levels - just enough to inject interference, ultimately into the critical D/A part of the circuit.
 
None. Not of the electronic type, anyway - I've never been close enough to the industry to have ready access to that type of gear. What I've worked with is experimentation with materials, and techniques which I feel could be relevant - and then used my ears to detect if a significant difference occurred ... sometimes no change, sometimes an improvement, sometimes the sound degraded - repeat until one is certain of consistent results.
 
As said these static charges do not build up inside active circuitry otherwise we would be in trouble....some data would be nice, as I have said and repeat I do not believe static charges build up inside active electronics, if it is affecting a D/A it could just as easily affect something critical in a life critical piece of equipment and POW!
Humans touching gear can create an ESD event, but again this is well studied and catered for.
That link again relies on a human to initiate the static event, not relevant.
 
In general, yes. But stage monitor wedges do need voicing, as the last thing you want on a noisy stage is a flat response speaker system. Now, I know you'll all say that's what EQ is for, but you want to save that for sorting out feedback problems.

I did not mean speakers I meant the active electronics involved in music reproduction. Though I think a lot of people if presented with a neutral system (a bit of wire with gain) would be disappointed and unhappy with the resultant sound, especially with a bad recording....
I am not immune from this and have both a solid state based set-up and a valve based, and dependant on my mood, and what I want to listen to will use one or the other knowing full well that one is not as accurate (or neutral) as the other, but I still enjoy the presentation.
 
Status
Not open for further replies.