peranders said:
One thing that struck my attention was that he seems to use several (10) small (1/4W?) 1 ohm resistors in parallel at the output, with two zobels (also with paralleled resistors).
I can think of a few reasons to do that, but also why not to.
Any ideas for why he is doing so?
Carlos
At this moment I have difficulty in picking drifferences with interconnects.
My pre-amp is responsible for this.
OPA627+BUF634 will drive any cable like there's no tomorrow.
I have a 5 meter Profigold interconnect between my pre and my power amp.
It's useless to spend more money with cables, using this pre.
Believe me, A-B with this and a 1000€ WireWorld and no difference.
I see someone thinking that my system is not transparent enough to show the difference, but no, that's not the case, I'm immersed with detail.
Anyway, Cat5 cable makes a very good interconnect.
Just don't use it as it is, take the conductors out and make the cable with identical pairs.
The problem is that every pair has a different crossing, some tighter, some wider, and that may affect the sound.
I've heard this effect with the first Cat5 interconnect I made, with all the wires, just put some RCAs and whites for ground, colored for positive.
Stupid mistake I made, bass was delayed with all the rest, really lowsy.
You just need two pairs, not the whole cable.
Or two wires for ground and one (central) por positive, the two ground wires crossed over the central one, a la Kimber.
It's what I do.
If shielding is not critical, this is fine.
Not for my TT, though.
My pre-amp is responsible for this.
OPA627+BUF634 will drive any cable like there's no tomorrow.
I have a 5 meter Profigold interconnect between my pre and my power amp.
It's useless to spend more money with cables, using this pre.
Believe me, A-B with this and a 1000€ WireWorld and no difference.
I see someone thinking that my system is not transparent enough to show the difference, but no, that's not the case, I'm immersed with detail.
Anyway, Cat5 cable makes a very good interconnect.
Just don't use it as it is, take the conductors out and make the cable with identical pairs.
The problem is that every pair has a different crossing, some tighter, some wider, and that may affect the sound.
I've heard this effect with the first Cat5 interconnect I made, with all the wires, just put some RCAs and whites for ground, colored for positive.
Stupid mistake I made, bass was delayed with all the rest, really lowsy.
You just need two pairs, not the whole cable.
Or two wires for ground and one (central) por positive, the two ground wires crossed over the central one, a la Kimber.
It's what I do.
If shielding is not critical, this is fine.
Not for my TT, though.
627+634
To carlosfm : If you have setup bias current on 634 to the higher value ( 12 - 15 mA ) and if is connected to the feedback of opamp, try the next : connect directly on output of pream in series resistor 51 R and the same resistor to the end of cable ( directly to the cinch ) in parallel. In this case will be gain 6 dB lower, but quality of sound rise 1000 %
, belive or not . More later after, when you try it .
To carlosfm : If you have setup bias current on 634 to the higher value ( 12 - 15 mA ) and if is connected to the feedback of opamp, try the next : connect directly on output of pream in series resistor 51 R and the same resistor to the end of cable ( directly to the cinch ) in parallel. In this case will be gain 6 dB lower, but quality of sound rise 1000 %
, belive or not . More later after, when you try it .
Re: 627+634
Actually I have 50 ohms output impedance, and yes, I never tried that, but some people told me to it may even sound better.
Some of these days...
1000%?
BTW, what do you mean about bias current, you mean bias into class A with a resistor?
Doesn't the BUF634 have lots of current as it is?
Is it necessary to bias here?
Upupa Epops said:To carlosfm : If you have setup bias current on 634 to the higher value ( 12 - 15 mA ) and if is connected to the feedback of opamp, try the next : connect directly on output of pream in series resistor 51 R and the same resistor to the end of cable ( directly to the cinch ) in parallel. In this case will be gain 6 dB lower, but quality of sound rise 1000 %
Actually I have 50 ohms output impedance, and yes, I never tried that, but some people told me to it may even sound better.
Some of these days...
1000%?
BTW, what do you mean about bias current, you mean bias into class A with a resistor?
Doesn't the BUF634 have lots of current as it is?
Is it necessary to bias here?
Carlos,
it sounds better. You will find it described at my www, item Audio Buffer.
http://www.pha.inecnet.cz/macura/buffer_en.html
it sounds better. You will find it described at my www, item Audio Buffer.
http://www.pha.inecnet.cz/macura/buffer_en.html
PMA said:
I know, Pavel.
If you remember, I made my pre based on your schematic for the buffer.
More gain, and some ideas, as the recommend 200pf cap.
I see now what you mean by bias.
Actually, I used a direct link between BW and V- so to test this I don't even have to open my pre, a thing I don't do for more than one year.