[diditmyself]

Quote:

Originally Posted by SpudHarris /img/forum/go_quote.gif For anyone interested I'm using BUF634's (Hi-C) but no opamps in G/V. More isn't always better!! just took me a while to discover that.

The ground channel really has to be low impedance and an open loop buffer like BUF634 can't make it on it's own. If you find the sound very different from using opamp/buffer you're listening to an erroneous sound now, not before. The lower the impedance of the phones the worse it gets, both crosstalk and distortion.

 

[SpudHarris]

Quote:

Originally Posted by diditmyself /img/forum/go_quote.gif The ground channel really has to be low impedance and an open loop buffer like BUF634 can't make it on it's own. If you find the sound very different from using opamp/buffer you're listening to an erroneous sound now, not before. The lower the impedance of the phones the worse it gets, both crosstalk and distortion.

I'm not technically qualified to comment on that, I use my ears to tell me what sounds good and what does'nt. All I can say is that I prefer the sound of a lot of my opamps now with dummy adapters in the G and G/V channels of my P3 amps. Don't know if it should sound better but it does. Ibasso despatch the stock P3+ with AD827 in L/R + Transistor Buffers and Dummy Adapters in G/V.

 

[Cynips]

Quote:

Originally Posted by fzman /img/forum/go_quote.gif Google Translatefound these in my web travels, and think they would be interesting for finicky opamps. this is the english translation, if i got it right. any thoughts, help from anyone in sweden re: pricing and availability? reputation of this company??

They seem like a serious business though I haven't had anything to do with them. Hardcore audiophiles if you ask me. For international orders you have to pay the actual shipping cost, whatever that is from Sweden to the US. Pricing seem decent, 1USD = 7.2SEK at the moment, so 35:-, e.g., would be almost $5 but since you don't have to pay Swedish VAT you can deduct 20% off of the price and would end up a buck less. I'd expect shipping costs to be about twice of what you'd pay to send the same thing from the US to Sweden.

Just ask if you have more questions or need any help with the translation.

 

[ROBSCIX]

Quote:

Originally Posted by Cynips /img/forum/go_quote.gif They seem like a serious business though I haven't had anything to do with them. Hardcore audiophiles if you ask me. For international orders you have to pay the actual shipping cost, whatever that is from Sweden to the US. Pricing seem decent, 1USD = 7.2SEK at the moment, so 35:-, e.g., would be almost $5 but since you don't have to pay Swedish VAT you can deduct 20% off of the price and would end up a buck less. I'd expect shipping costs to be about twice of what you'd pay to send the same thing from the US to Sweden. Just ask if you have more questions or need any help with the translation.

I am unsure without looking at the design but usually when caps are that close to oapmps, they are not used in a attempt to make the module sound better.
They are used to stabalize opamps which are high speed and tend to osciallte. Depending on how the caps are used they can stabalize the opamps in many ways. They can be used to "slow down" the opamp or decouple them from the power as many times the supply can cause oscialltions. I am just guessing though based on a quick look.

 

[fzman]

cynips -- thanks for the offer. i may try to place an order for some soon. perhaps other head-fiers would want some as well.

robscix -- you are correct, the caps "slots" are for rail to ground and rail to rail decoupling caps, which can both stabilize and "make them sound better". it's much easier, so it would seem, to do it on these boards, if they'll fit, than to hack away at it, and have long leads, and dangling parts --

 

[ROBSCIX]

Yes, I know what they are for. I was just explaining to Cynips as I wasn't sure what he meant by his post.

 

[Bonthouse]

Okay, I've had the AD797A a few days now in my Corda Meier Move and I must say.. I'm in love.

Lows extend way lower, highs are sparkling, mids are fun to listen to. Detail and speed are very nice and the sound is absolutely not fatiguing

It has a little less detail and speed than the LME49710, but this one makes my head nod, this one has soul!
Highly recommended!

 

[ROBSCIX]

I have a AD797A and while I find it a good opamp, it is definately not the end of the road for me.
If it is a musical amp in your application, that is good. Many opamps might not have the high detail that others have but they get your toe tapping and that is the main thing.

 

[fzman]

guys,

something i've been trying to find is a comparison between the ad8599 and the ad8022. this would be on browndogs, as the buffer/ diff to single ended opamp on a prodigy hd2 sound card; with opa2604s as low pass (voltage dac akm4396), so it is not i/v.

i've tried several combos and so far the majkel recommendation of 2 x 2604 and 1 x 8022 sounds very very good. the 8022 is very fast, but is not oscillating, at least so far as the temperature test is concerned. i haven't put it on the scope yet, even though i have one and sorta know how to use it.....

this combo, as i mentioned above, sounds very good-- very open, good timbres, dynamics, good precise imaging etc.... it does seem to slightly accentuate upper mids - cymbals, etc, and can get just a touch edgy on bad cds.....

would sustituting the 85999, which i just browndogged, keep the resolution but give it a touch more balance, and that natural glow and coherence???

please answer in the space provided, and show your work!!!

don't you just love a pop quiz

 

[ROBSCIX]

Try it out and let your ears be the judge.
The 8599 seem highly regarded among many for audio use. I built a few the other night along with a whole mess of other ones. I create a list and then just sit and build then work on the next list

My intial test seem very quite promising.

 

[acvtre]

I've found a great ebay opamp and ADs seller and I'm going to buy a bunch of ICs. Do you have something to suggest such as a must-have list?

 

[SpudHarris]

Trade you for his details!

 

[majkel]

@fzman, you can try the OPA2228 instead of the OPA2604. My friend did it and found it as an improvement. The buffer might be the AD8599 or the AD8022. The AD8019 could probably work as the output buffer as well as the AD8397. Everything is to try out.

 

[Cynips]

Quote:

Originally Posted by fzman /img/forum/go_quote.gif cynips -- thanks for the offer. i may try to place an order for some soon. perhaps other head-fiers would want some as well. robscix -- you are correct, the caps "slots" are for rail to ground and rail to rail decoupling caps, which can both stabilize and "make them sound better". it's much easier, so it would seem, to do it on these boards, if they'll fit, than to hack away at it, and have long leads, and dangling parts --

Weird, seems all my subscriptions here at head-fi expired

Anyway, they write on that page about using these adapters to make things like CD-players sound better. Can't find any reference to stabilization, just that they're using capacitors to decouple the supply voltage (if I'm translating this right). If you really want to know you could try mailing to that guy at the address supplied: sigurd@ruschkowski.se

 

[ROBSCIX]

Quote:

Originally Posted by Cynips /img/forum/go_quote.gif Weird, seems all my subscriptions here at head-fi expired Anyway, they write on that page about using these adapters to make things like CD-players sound better. Can't find any reference to stabilization, just that they're using capacitors to decouple the supply voltage (if I'm translating this right). If you really want to know you could try mailing to that guy at the address supplied: sigurd@ruschkowski.se

I was just commenting on capacitor use in regards to opamps in a general sense. They can be used for stabalizing opamps which are touchy and prone to oscialltion. They are also used for other tasks depending on the design.

I have seen a few upgrade modules now with caps built into the module. Most are meant for upgrading older CD players as you suggested.