audio-talk

Not sure what the frequency response is showing, whats all the noise I used the spectrum analyzer with a sweep signal 10Hz-50kHz/10ms/10Hz intervals and flat top/peak hold.What you see on the bottom of the curve are the measurements/probes in very short time intervals and without "flat top&quo...

As I try to avoid grid stoppers - and I don't think the 2k which S.Bench uses in his original circuit would change anything because of the low value - would an anode bypass cap parallel to the 60k anode resistor of the second 6SN7 triode help to shape the high frequency response a little?

Also the 'higher tempo' effect seems to come when bass time constants are reduced or eliminated. I don't fully understand what you mean with "reduced bass time constants" in this context. Maybe the following makes it clearer what I mean. The bass seems first "less" powerful comp...

Last night I connected the Inv OTL to my main system. Left channel the 6C33 SE OTL, right channel the Inv OTl. Their input sensitivity is almost the same so there was no real need for adjustments. The 6C33 sounds excellent and I thought this would be a fair comparison. Normally when I do these tests...

I was meaning would it be useful as a starting point rather than as the end solution but Nick has picked up on this now so hopefully it'll help you address the DC issue.

It helped me to start thinking out of the box because I was too focused on this one thing I had in mind.

I might build a raw one without the stuff you’re planning

That's all you need in this case: The chokes are Hammond, 159V.

Thanks, Nick. I will try this thing with the nsl32. Should work and would solve the only remaining little problem with this amp.

A set of output tubes starts to look expensive though but I see there are some Russian equivalents to the 6AS7 that might be an option. Regarding managing the DC offset, I don't know if this might be useful? I ordered 12 of these, $10,72 per tube. They seem to be fine tubes. https://www.parts-expre...

Do I unerstand correctly that you're using regulated supplies? That's right, Ray. For the driver stage I use 2 Maida regulators in order to get the +/-350V. They are perfect for this job. Only down side is that it needs 2 transformers or one transformer with two separate sec. windings in order to m...

The pdf of the schematics couldn't be opened in my last post. Don't know what went wrong but here it is: schematics.jpg What interested me was the ability to get a fairly low output impedance without using feedback. This is indeed the most interesting aspect of using an amp like this. With six 6AS7 ...

When I saw the schematics of the Inv OTL my first thought was that building this amp could be a way out of something which had become more and more part of my daily listening experience. This feeling of having reached a dead end is no doubt very subtle because I am quite satisfied with the sound of ...

At the end of the day it always comes down to what sounds best for the individual...

Couldn't agree more, Ray.

I tested HQ Player in my system some time ago. So I am not completely unfamiliar with it but at the same time I cannot say that have enough information to be sure how to interpret the real effect of what is called the “Resampling Filters”. I guess that’s what we are talking about in this context. Ar...

I hope I don’t upset anybody or go too much “off-topic” with this comment but in my limited understanding the strength of the Soekris R-2R DAC lies in the possibility to adjust the balance between low pass filter linear phase and (unavoidable) passband ripples which can be described as pre- and post...

The "thin" impression comes mainly from the NFB, the LM 317, and the CCS. Same thing with the 300B SE OTL.300Bs should sound fuller and warmer in the midrange. Less "glassiness" can be achieved by using star grounding with as short as possible wires replacing the "ground pla...