Re: Countrepoint in action.
Not sure what the rails are, but how much p-p voltage could this swing (balanced)?
Tom
Russ,Russ White said:Counterpoint sounds very nice indeed!
I have been running it all day.
It is nice and quiet when it should be, and just sounds "right".
The counterpoint can run in two modes. Zero global feedback mode, and emitter feedback mode. I found it difficult to make the emitter feedback mode work correctly, but ZFB mode is working like a champ!
I have the input bias voltage set at 1.65V This does wonders for the buffalo!!!
Here is how it looks, the light are hypnotic.
Not sure what the rails are, but how much p-p voltage could this swing (balanced)?
Tom
Each Counterpoint is only a single channel. You have no choice but to use two.
Actually, this is a good opportunity for me to ask an additional question, for those of us interested in Counterpoint but restricted to unbalanced equipment. I know that IVY can be configured exclusively as a balanced to unbalanced converter. But it seems to be a waste to use Counterpoint for I/V duties, then run everything through a dual OPAMP as in IVY.
So is there any future possibility, however remote, that you will make a 'better' balanced to unbalanced converter? I don't know what form it could take...... discrete components? A more 'deluxe' OPAMP implementation?
Cheers!
Actually, this is a good opportunity for me to ask an additional question, for those of us interested in Counterpoint but restricted to unbalanced equipment. I know that IVY can be configured exclusively as a balanced to unbalanced converter. But it seems to be a waste to use Counterpoint for I/V duties, then run everything through a dual OPAMP as in IVY.
So is there any future possibility, however remote, that you will make a 'better' balanced to unbalanced converter? I don't know what form it could take...... discrete components? A more 'deluxe' OPAMP implementation?
Cheers!
As I had some to hand, I too tried the Wima (fkp 10000pf) modification like Fran, although I did not bypass the resistors... (I'm not sure of the point of this? - but it is easy enough to do.. maybe I should?)
(For reference the rest of system for this test was a MacMini feeding lossless into DAC (Buffalo/IVY) via optical (TOSLINK) into TVC and then Welborne Labs Terraplanes (300B valve amps) to Beauhorn B2.3's speakers. All single ended.)
I've only had a small amount of listening time with it in this configuration, but here are my two pennies worth.
1. Definitely appears to be more detailed. Less sharp somehow, but more stuff is present, little nuances, cymbals cleaner, that sort of thing.
2. The sound stage is definitely different, before it was a bit left and right. Now it seems to have better depth or layering back from the left and right to the center. I like it.
3. I already seem to have some sibilance, but I did not notice any more in this configuration.
4. I'm not sure about the more fluid? Could be just a problem with terms. But it definitely has more attack and pace.
As an alternative to the system above, I also tried the DAC direct in to the power amps, using the iTunes volume control via the Apple 'Remote' software on the iPhone/Touch. (What a great remote control!)
I'm not sure of the input independence of the Terraplanes, or the ability of the IVY to drive them and of course the volume on the remote was down way low as I think the Terraplances only need about 1.5v to hit max. But, the sound was incredibly detailed, a little bit hard, perhaps a bit less musical (maybe some mis-match here between the DAC and Power Amp), but very, very good.
Very HiFi ;-)
Also I'm not sure how good the iTunes digital volume is? Maybe a better digital volume control and the Counterpoint maybe the solution for such a direct connection?
Anyway I'm going back to the TVC route as it seems more musical, at least to these old cloth ridden ears. (The other route show promise though and makes for a very compact system!) Either way I think this mod stays. I'll report back if further listening changes these opinions.
Hope this helps,
Russ
rjbaldwin - seems like you heard pretty much exactly what I heard. All in all I think this marks a good step up for this DAC in terms of listenability long term. Problem now is that I know some smart cookie is gonna come along and say, "Oh fkps, well yes they're ok, but I really like [insert brand here] you should hear the difference with them". And then we'll feel like we're missing something!
Agree with you on the detail and the front to back depth being improved. Maybe fluid is a bad term, its what kinda made sense to me, but maybe timing is more accurate.
Anyway, Russ/Brian, what about that use of a counterpoint in SE mode for those of us who haven't taken the plunge into balanced?
Fran
Agree with you on the detail and the front to back depth being improved. Maybe fluid is a bad term, its what kinda made sense to me, but maybe timing is more accurate.
Anyway, Russ/Brian, what about that use of a counterpoint in SE mode for those of us who haven't taken the plunge into balanced?
Fran
Russ White said:There is no really good reason to go > 10nf. I would try 1nf, 4.7nf, and 10nf.
Basically what the cap does is force the input slew rate to be less than the maximum slew rate of the opamp.
In my simulations and testing I find 10nf to be pretty ideal. Higher and you start to get more distortion.
Cheers!
Russ
Russ
I have just tried 10nf whlist listening to sacd via dsd and I like it. Smooths hf and seems to improve transients.
Whats the news with the right comparator for 192k on the Buffalo?
Fred
Spartacus said:
THD is ~ -117db for 20hz to 20khz.
Because of the symmetrical nature of the cct the PSSR is nearly perfect. Well above > 140db (sim says -240db, but I find that hard to believe) for the balanced outputs even into the 10MHz range.
For SE use it goes from 104db at 20Hz to about 55db at 20kHz.
One cool factoid, the cct itself draws a constant current, regardless of the load or frequency. So it will not induce any ripple of its own. Or rather very very little.
Cheers!
Russ
Counterpoint update
OK so I need to revise my statement about SE output with counterpoint.
While it both works and sound great, there is one issue which will likely not make it practical for many.
It has pretty nasty turn-on, and turn-off transients when used single ended. So you would need a relay or something to switch the output to GND at power off.
Balanced output does not have the same issue as the change is common mode. So turn-on and turn-off are non-eventful for balanced gear.
Cheers!
Russ
OK so I need to revise my statement about SE output with counterpoint.
While it both works and sound great, there is one issue which will likely not make it practical for many.
It has pretty nasty turn-on, and turn-off transients when used single ended. So you would need a relay or something to switch the output to GND at power off.
Balanced output does not have the same issue as the change is common mode. So turn-on and turn-off are non-eventful for balanced gear.
Cheers!
Russ
glt said:
Well, it is definitely great. I don't know if I could pick between the two.
The counterpoint seems t have a bit "earthier" feel to it. Very natural. I can't really describe it, but now I think I know why people like zero feedback designs.
Contrast is nice and sharp. Sound stage is well defined.The counterpoint does have a very very faint hiss (pretty common with bipolar ccts). I have to put my ear close to the driver to hear it, and this is really only because I have the counterpoint connected to directly to the power amp. There is no analog attenuation to knock it down. I am controlling the volume digitally at the DAC.
I am very pleased with the results. If you made a Plexiglas case it will make a nice nightlight.
Cheers!
Russ
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