Forgot about Kimber. Nice with those colour options for a clean look. Probably great sound too. I've read somewhere that the black isolation variety sounded worse than the other colours available. Crazy or true?
Solid silver. Well that's my siren. I probably have to try it sooner rather than later. What's the gauge and do you twist it for hum rejection?
Solid silver. Well that's my siren. I probably have to try it sooner rather than later. What's the gauge and do you twist it for hum rejection?
I don't know, black is in the ground bus.
I use in my 10/VT-25/801 preamp 24 awg solid silver with teflon jacket in the signal path (hot and "ground" too).
TCSS is rigid as hell, but this outbidding it.
Almost unable to twist it.
HT and filament wiring is made from Habia silver plated stranded copper (twisted).
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I use 0.4mm, just a single run, and that works fine in the 26, but with the hum I have in the 01A I will try screened wire. And if that works, reinstate the solid silver but add a screen to it.
EDIT. I see that 24 AWG is 0.5mm, and 26 AWG is 0.4mm. I have read somewhere that 0.3mm is ideal, but I refuse to obsess about it. I save that for capacitors!
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Way too much! At least for my system, where a passive TVC was quite enough.
Anybody tried Ale’s gyrator output into an eg. 4:1 line transformer to reduce the gain?
In addition to reducing the gain, you would also get galvanic isolation. However with this configuration I do not see the benefit of the gyrator vs. using a 4:1 parafeed transformer, and no gyrator... if not the gyrator represents a much better anode load than a transformer.
Any thoughts?
I use it in step down for a headphone amp. This is because I wanted to use a good quality Sowter OPT which isn't gapped for DC. I use a 6J49P wired in triode with some degeneration in the cathode and a gyrator load. The OPT is coupled as Parafeed so there is a coupling cap to avoid DC load. The result is great and I love the design.
The trade off of the gyrator design is that you get in some cases more gain than is needed. People then complain about the microphonic noise or even the hum (due to poor ground wiring in most cases) when the resulting system has far too much gain.
I use either a 26, 4P1L, 01a or VT25 preamps which all have similar gain to drive directly a 4P1L PSE output stage, no driver.
It's probably the best system I have had by far. The combination of Rod regulators with the gyrator and good wiring/layout, results in a complete hum-free systems 100% DHT. This has been the result of years of trailing and testing, refining various options.
Andy Evans can also comment re the system setup as we currently have both a similar one.
Ale
I'm a little puzzled at these two posts. Is Rod saying don't use a TVC after the gyrator? And is Ale saying that he does? I am, as the hum was excessive (I will work on this anyway), so using the TVC on the back end instead of the pot on the front has cleaned it up beautifully. And to my tired old ears it sounds damn good! Better than the transformer coupled 26, anyway.
Ale is using parafeed transformers - these are designed to be used with an anode load, which handles the dc current (Gyrator is perfect for this). The Parafeed trafo cannot handle the dc current though - so it must be cap-coupled to the Gyrator.
Parafeed trafos have advantages - look them up! Sowter makes some nice examples, too.
The Parafeed example is a very different case to using an ordinary output trafo (OT) - i.e. one that can handle dc current - which should be used without other anode loads.
Parafeed trafos have advantages - look them up! Sowter makes some nice examples, too.
The Parafeed example is a very different case to using an ordinary output trafo (OT) - i.e. one that can handle dc current - which should be used without other anode loads.
Sorry.Watch your language!!!!! Remember that you are on the 26 thread now
Which might explain why the LL2745 coupled 26 didn't sound as good with the TVC on the output, as it did with the TKD pot on the input?
I use CCS loaded #26, and -practically parafeed- capacitor coupled S&B TVC (400H!).
TVC/AVC is sensitive to driver stage output impedance (use as low as possible), so CCS or even low output impedance gyrator is a good choice.
For me the -good- TVC is much more musical than other passive volume controllers.
BTW I love Noble, TKD or black beauty Alps potmeters, but my S&B or the nano core Promitheus (core size as SU90!) is the other league.
TVC/AVC is sensitive to driver stage output impedance (use as low as possible), so CCS or even low output impedance gyrator is a good choice.
For me the -good- TVC is much more musical than other passive volume controllers.
BTW I love Noble, TKD or black beauty Alps potmeters, but my S&B or the nano core Promitheus (core size as SU90!) is the other league.
Regarding output caps for the gyrators, yesterday I tried my two 0.22uF 200V FT-3 capacitors yet again after at least 250 hours of burn in my Frybaby burn in apparatus. And, I have to eat some humble pie here, they are in fact very good in this 150V and relatively high level output position. And not boring at all. So Mr. Evans you were right all along.