I know the reason is me, my misunderstanding but I cannot figure it out: why the Pass pre I built with the Burning Amp board works and works well no matter in which system I put it but my build of Waynes Line Stage makes a hidious noise in one system and is fine when used with a Pass (F6) amp and ordinary CD player.
I would think that it would be all or nothing, I made a mistake somewhere but that WLS is a gem in one systen and Seriously non-funtional in the other. While the BA pre is unflappable. Oh, to be fair the WLS uses output caps just like the BA... the DC offset was not tamable with just the pots so that difference is not a difference. I don't understand, what makes a preamp just a hidious noise maker only in some situations? Please, Help me understand!
I would think that it would be all or nothing, I made a mistake somewhere but that WLS is a gem in one systen and Seriously non-funtional in the other. While the BA pre is unflappable. Oh, to be fair the WLS uses output caps just like the BA... the DC offset was not tamable with just the pots so that difference is not a difference. I don't understand, what makes a preamp just a hidious noise maker only in some situations? Please, Help me understand!
Might try different cables between the two. Just a starter thought. Had a similar situation that had me chasing my tail for days once. And that is all it was.
What is hard to explain is, why there are hundreds of reviews here on diyAudio saying "Waynes Line Stage is the best sounding piece of gear I have ever bought or built!". If your WLS sounds bad, is that because (a) your ears are bad; (b) your WLS is built wrong; (c) WLS truly IS bad and you are right while hundreds of other WLS builders/listeners are wrong ? ? ?
But what is said it is that it is fine in one system and not the other.
“I put it but my build of Waynes Line Stage makes a hidious noise in one system and is fine when used with a Pass (F6) amp and ordinary CD player.”
Hideous noise may be sign of oscillation. Its quite possible to oscillate in one system and not in the other.
excessive gain sum of system?
recently we had exactly that , WLS combined with power amp (having plenty of db), feeding Klipsch Heresy
same as using ferrari to bring ton of concrete
horses for courses
recently we had exactly that , WLS combined with power amp (having plenty of db), feeding Klipsch Heresy
same as using ferrari to bring ton of concrete
horses for courses
I know it’s a bizarre situation, more reflection gets me recalling the same thing happening with a TVC. I mentioned that I ended up using an output cap to get the last of the DC offset gone on the WLS (by the way it sounds fine with the use of an output cap 🙂 Do you guys think maybe I should install an input cap? I don’t recall if ther is one on the BA board…
I believe the OP’s issue may have something to do with the WLS JFETs, and that the noise comes from there, possibly affected by different sources varying output impedance and poweramps input impedance. I support measurements. DC offset issues is a great storyteller for JFET issues.
I had a DC offset/bias problem with my build which was traced to some flux residue around the jfets. Cleaning that properly resolved the issue for me.
10 years in I'm still a noob - All I have is a multi meter (self ranging) so I am not so hot at live measurements. I consulted the manuals ;-)
I also usually do the swaps that help define the problem and it occurs to me now that I failed to do one: swap CD players.
The DAC (California Audio Lab) seems to be the part of the system that makes the WLS crazy, when I switch to an ordinary CD player (Magnavox CDB 472) the WLS is fine. It has nothing to do with the amps 🙂
The difference between the DAC and the CD is in the output. DAC is 3.5V rms at 2k ohms - CD player is 2V rms at 200 ohms. Full disclosure I have two California Audio Labs DACs, one reset to 2v rms out, that one works fine with the TVC mentioned earlier, the other one is factory set to 3.5V rms - that is the one befuddling the WLS (and the TVC). Again, the regular CD player to WLS to Pass amp OR any amp, works fine.
So it must be the 3.5V rms/2k ohm out freaking out my gear (though it does NOT freak out the BA preamp or my Supratek Chennin ;-)
I'm open to ideas to make the WLS function with the 3.5V/2k DAC.
I am guessing that the 60k pot for volume control-in-parallel-with-the-100K-input-resistor-(R18) is the issue.
I also usually do the swaps that help define the problem and it occurs to me now that I failed to do one: swap CD players.
The DAC (California Audio Lab) seems to be the part of the system that makes the WLS crazy, when I switch to an ordinary CD player (Magnavox CDB 472) the WLS is fine. It has nothing to do with the amps 🙂
The difference between the DAC and the CD is in the output. DAC is 3.5V rms at 2k ohms - CD player is 2V rms at 200 ohms. Full disclosure I have two California Audio Labs DACs, one reset to 2v rms out, that one works fine with the TVC mentioned earlier, the other one is factory set to 3.5V rms - that is the one befuddling the WLS (and the TVC). Again, the regular CD player to WLS to Pass amp OR any amp, works fine.
So it must be the 3.5V rms/2k ohm out freaking out my gear (though it does NOT freak out the BA preamp or my Supratek Chennin ;-)
I'm open to ideas to make the WLS function with the 3.5V/2k DAC.
I am guessing that the 60k pot for volume control-in-parallel-with-the-100K-input-resistor-(R18) is the issue.
even for 2Vrms source, WLS is having too much gain, when used with regular power amps
set WLS to 2* to 3* gain, and be sure that CAL dac is not having issues with output
try CAL followed with simple 10K Vol pot, feeding F6, and make your own conclusions
btw, 100K input impedance of preamp calls for 10K Vol pot; which is too low for 2K output impedance of CAL
weird logic, they had; POS , as far as I'm concerned, even if "just" a way to urge use of some special (their) preamp, having at least 100K of effective Rin
set WLS to 2* to 3* gain, and be sure that CAL dac is not having issues with output
try CAL followed with simple 10K Vol pot, feeding F6, and make your own conclusions
btw, 100K input impedance of preamp calls for 10K Vol pot; which is too low for 2K output impedance of CAL
weird logic, they had; POS , as far as I'm concerned, even if "just" a way to urge use of some special (their) preamp, having at least 100K of effective Rin
Thank you! I need to know though, how to "set WLS to 2* or 3* gain..." I think I can whip up in interconnect with a 10k pot in line with the positive wire if that is what you intend... to go between the "POS" DAC and the WLS.
Let me be more specific: if the idea of seeing gain is achieved through the ratio of R16 and R17 (27k to 10K in the schematic) and raising R17 will reduce gain... to hit that 2* or 3* raise R17 to what?