6h5c said:
Hi Allan,
I have that one in my bookmarks list already, very useful site, thanks anyway.
I still have to try that class-A....have to make a to-do list for those things, I keep forgetting it.
Ray.
Thought i'd already posted it
decoupling opa's does work well. (on pins)
also small electrolytic(100uf) on power supply's close to the chip.
been tried on, and refined, on opamp headphone amps (headwize)
class A on the filter opamps? dunno anything's worth a try
allan
gy21 said:
Yes, but I have only a 220n PPS fitted on the back of the PCB. I swap adapters now and then, and experiment with different types of opamps. If I don't like a certain combination, I solder some caps directly on the adapter to see if it makes a difference. If it doesn't help I take them off again.
Not all models are equally critical with decoupling. The faster opamps tend to be more sensitive, especially if you place them after the DAC, where they get more high-frequency signal. Types like LM6172, AD8065, AD825/826, AD8610, LT1360/1361, THS4631.
But it is more difficult to tell which one is critical if you use two single opamps
.Ray.
6h5c said:
Yes, but I have only a 220n PPS fitted on the back of the PCB. I swap adapters now and then, and experiment with different types of opamps. If I don't like a certain combination, I solder some caps directly on the adapter to see if it makes a difference. If it doesn't help I take them off again.
Not all models are equally critical with decoupling. The faster opamps tend to be more sensitive, especially if you place them after the DAC, where they get more high-frequency signal. Types like LM6172, AD8065, AD825/826, AD8610, LT1360/1361, THS4631.
But it is more difficult to tell which one is critical if you use two single opamps
Ray.
Hi.
The combination I would like to try is LM6171 after the DAC with OPA627 in class A as filter. [mainly because the LM6171 is a symmetrical design and therefore better suited to differential working]
Andy
Hi everyone,
Only a vaguely relevant question, but would you advise against using too many of a certain op-amp type in one system?
I use OPA627 x2 in my CD63, and in my preamp I use 2x LM6172 (two gain stages). Compared to OPA2134 (preamp recommended opa) the 6172 sounds a bit aggressive (but cured the blandness of 2134). I am extremely tempted to find some more 627s to use in my preamp and have the benefits of this chip all the way. But will I have too much of a good thing???
I know that was a stupid question and the answer is to try it and see, but I would like to know peoples' opinions on mixing opamps for the best overall flavour. Start to finish my system uses 5 opamps per channel!
My [limited] experience with bypassing:
Small electrolytic caps from + and - to ground work wonders. 4 of my opas use Panasonic FC 33uF/50v and this really cleans the sound up (well, it did compared to no bypassing on the 2134: I've not taken them out since). My power amp chips (LM3886) use Rubycon ZA 100uF/50v, and these also work well. If you want tried and approved use some of those caps, you can't go wrong.
All the best,
Simon
ps - my display is still dead and I think I'll order a 7912 or 15 to replace the regulator, see if that helps. Hopefully will order that today.
Only a vaguely relevant question, but would you advise against using too many of a certain op-amp type in one system?
I use OPA627 x2 in my CD63, and in my preamp I use 2x LM6172 (two gain stages). Compared to OPA2134 (preamp recommended opa) the 6172 sounds a bit aggressive (but cured the blandness of 2134). I am extremely tempted to find some more 627s to use in my preamp and have the benefits of this chip all the way. But will I have too much of a good thing???
I know that was a stupid question and the answer is to try it and see, but I would like to know peoples' opinions on mixing opamps for the best overall flavour. Start to finish my system uses 5 opamps per channel!
My [limited] experience with bypassing:
Small electrolytic caps from + and - to ground work wonders. 4 of my opas use Panasonic FC 33uF/50v and this really cleans the sound up (well, it did compared to no bypassing on the 2134: I've not taken them out since). My power amp chips (LM3886) use Rubycon ZA 100uF/50v, and these also work well. If you want tried and approved use some of those caps, you can't go wrong.
All the best,
Simon
ps - my display is still dead and I think I'll order a 7912 or 15 to replace the regulator, see if that helps. Hopefully will order that today.
SimontY said:Hi everyone,
Only a vaguely relevant question, but would you advise against using too many of a certain op-amp type in one system?
I use OPA627 x2 in my CD63, and in my preamp I use 2x LM6172 (two gain stages). Compared to OPA2134 (preamp recommended opa) the 6172 sounds a bit aggressive (but cured the blandness of 2134). I am extremely tempted to find some more 627s to use in my preamp and have the benefits of this chip all the way. But will I have too much of a good thing???
All the best,
Simon
ps - my display is still dead and I think I'll order a 7912 or 15 to replace the regulator, see if that helps. Hopefully will order that today.
Hi Simon,
All opamps have a certain characteristic sound, and if you use too much of the same it may become overly present. I agree about the LM6172, I don't like it as a dual opamp in my player. On the other hand, I found a dual OPA627 setup sounds too "brown"
. So I think the key is to get the right mix.The same is valid for the use of resistors or silver wiring, i've experienced that in my tubeamp.
Good luck on that display!
Regards,
Ray.
6h5c said:
Hi Simon,
All opamps have a certain characteristic sound, and if you use too much of the same it may become overly present. I agree about the LM6172, I don't like it as a dual opamp in my player. On the other hand, I found a dual OPA627 setup sounds too "brown"
So I think the key is to get the right mix.
The same is valid for the use of resistors or silver wiring, i've experienced that in my tubeamp.
Good luck on that display!
Regards,
Ray.
Hi Ray, thanks for the reply. I'm quite good with my subjective terminology I think, but for my edification and for others, can you describe what "brown" means please? I think it's easy to assume what "white" or "grey" means, but brown I'm not too sure about...
The LM6171/2 may well be sensible as a single to just give a hint of the positives (subjective speed, dynamic slam, bass impact, detail). Or I could use one dual for one gain stage in the pre and in the second socket a 2134 ('safe pair of hands', bland) or 627 (amazing in all ways: the antidote to poisonous digital sound). I intend to try some things...
Just need to fix that pesky display... lol!
SimontY said:
Hi Simon,
I mean a bit "dark" sound, with not-so-sparkling highs and more presence of the low-end. A little bit like heavy curtains hanging in front of the speakers. The mids are very nice and sweet (good with vocals), but maybe a bit too sweet. You could call it laid-back. The OPA132 also has it a bit, but less than the 627. It is known as the "Burr-Brown sound" (hence the "brown"
). I tried the OPA227 and OPA602 and those are even less "brown". It may be a good (and cheaper) substitute for the 627.Ray.
These last few pages have just reminded me there is something I have not done yet. Itchy fingers time....
So i'm going to do the old opamp bypass mod.
To compliment the 4 BG 16V 470uF caps next to the opamps i'm ordering some BG 10uF 50V jobbies for +/- de coupling.
They are 8X11 mm so size wise they will be fine.
I have 4 OPA627 on back order and was going to fit these to compare to my OPA132 / OPA627 setup so Ray I am interested in what "Brown" means (poo , crap , **** etc)
Brent
EDIT Ray you beat me with your answer LOL
So what else do you recomend to go with the OPA627 other than OPA132.
Brent
So i'm going to do the old opamp bypass mod.
To compliment the 4 BG 16V 470uF caps next to the opamps i'm ordering some BG 10uF 50V jobbies for +/- de coupling.
They are 8X11 mm so size wise they will be fine.
I have 4 OPA627 on back order and was going to fit these to compare to my OPA132 / OPA627 setup so Ray I am interested in what "Brown" means (poo , crap , **** etc)
Brent
EDIT Ray you beat me with your answer LOL
So what else do you recomend to go with the OPA627 other than OPA132.
Brent
6h5c said:
Hi Simon,
I mean a bit "dark" sound, with not-so-sparkling highs and more presence of the low-end. You could call it laid-back. The mids are very nice and sweet (good with vocals), but maybe a bit too sweet. A little bit like heavy curtains hanging in front of the speakers. The OPA132 also has it a bit, but less than the 627. It is known as the "Burr-Brown sound" (hence the "brown"
Ray.
Ahha, well the way you describe the brown sound is where those chips (amongst other ways) made my system more balanced, as it was too sterile previously. My speakers are relatively analytical and they appreciate the warmth and grain-free sound afforded by the 627s. That's not to say my system isn't dark overall, it is. But it sure sounds better than ever!
How good are these caps for decoupling?
N type
http://www.hificollective.co.uk/components/black_gate_caps.html
I was looking at the Nx HiQ 0.47uF
http://www.hificollective.co.uk/components/black_gate_n_type.html
I was thinking of using these with the BG 10uF 50V ones.
Brent
N type
http://www.hificollective.co.uk/components/black_gate_caps.html
I was looking at the Nx HiQ 0.47uF
http://www.hificollective.co.uk/components/black_gate_n_type.html
I was thinking of using these with the BG 10uF 50V ones.
Brent
