[mrdon]

I have begun modding my Denon 2900. I started with the opamps. First, opa627's and finally AD8620. I prefer the latter over the the stock opa270's and the opa627's. I love the AD8620's clarity but they are a little light in the mids. Anyway, I am wondering if I can "color" the sound; that is, regain some warmth. Could I do this by

• Replace the stock output caps with warmer ones?
• Adding bypass caps to AD8620?
• Upgrade the Power Supply by replacing stock PS caps with 20% larger capacitance caps (same voltage)?

Any other ideas?

 

[peranders]

The problem you have is that you don't seem to know how the sound is when it is treated without any losses or additions. When you don't know that you also don't know what to do.

Of course all good high quality opamps should have decoupling caps. This is nothing you think about really. The question is only how much.

When you mod a pcb which not is designed for the new opamps you may not be able to create a good environment for them. OPA627 is a single opamp in a dual place. This may have been a non optimal situation using a Brown Dog adapter or similar, with any additional decoupling I'll suppose.

 

[mrdon]

I thought of a non-invasive tweak. I took the Cryo-Treated Marinco 5266 AC plug off my Alan Maher DIY power strip and put the much warmer Leviton 5266 on instead. Some people don't believe plugs make a difference but to my ears they do. For now, this has warmed up things a bit. I will live with it for awhile and see how things go. Neverthless, I would like to hear others opinions on internal tweaks listed above.

 

[grandenigma1]

That sounds like a reasonable solution for now... you could also pick up some fuller warmer ICs if you do not already have a set... if the power cable greatly aided a set of ICs will help all that much more. Perhaps a set of 18awg copper cables or gold alloy

 

[mrdon]

Quote:

Originally Posted by grandenigma1 That sounds like a reasonable solution for now... you could also pick up some fuller warmer ICs if you do not already have a set... if the power cable greatly aided a set of ICs will help all that much more. Perhaps a set of 18awg copper cables or gold alloy

I am using Kimber PBJ currently, which in comparison to the DIY Mogami starquad IC's, brought back some warmth. Do you think 18awg copper will make thing even warmer than the PBJ?

 

[Ikon]

Considering that AD86x0 is one of the coldest sounding SOBs I have ever heard, I would really get another op-amp.

AD8066 and AD823 retain much of the typical ANALOG clarity and still have a warmer/sweeter sound than the AD8620.

 

[mrdon]

Last night I soldered two AD8066's on a DIP adapter with a .47uf/50v BG PK cap to both V+ to V- rails. I installed them this AM and took a preliminary listen. WOW! Thanks for the recommendation. I still have the detail and high and low extension of the AD8260's but the midrange just blooms. Thanks guys for your help!

 

[fewtch]

Quote:

Originally Posted by Ikon Considering that AD86x0 is one of the coldest sounding SOBs I have ever heard, I would really get another op-amp.

What... cold? That's not how I hear it at all. Sounds very lively, warm and energetic to these ears.

Quote:

AD8066 and AD823 retain much of the typical ANALOG clarity and still have a warmer/sweeter sound than the AD8620.

I found the AD8066 to be an extremely boring opamp... dull, plodding and matter-of-fact sounding. Just the opamp one would want for background music.

 

[grandenigma1]

Quote:

Originally Posted by fewtch What... cold? That's not how I hear it at all. Sounds very lively, warm and energetic to these ears. I found the AD8066 to be an extremely boring opamp... dull, plodding and matter-of-fact sounding. Just the opamp one would want for background music.

Are you basing all of these critiques of opamps off of use in your go-vibe? Because I don’t see any other amp listed that you could have tried these various opamps in. For instance in my PPA I greatly like the 627s where as my M3 I do not at all...

 

[mrdon]

Quote:

Originally Posted by fewtch What... cold? That's not how I hear it at all. Sounds very lively, warm and energetic to these ears. I found the AD8066 to be an extremely boring opamp... dull, plodding and matter-of-fact sounding. Just the opamp one would want for background music.

Again, it all comes down to the variables of systems gear, placement, room acoustics, and our God-given ears; that is, we are all uniquely created and our gear is too!

 

[fewtch]

Quote:

Originally Posted by grandenigma1 Are you basing all of these critiques of opamps off of use in your go-vibe? Because I don’t see any other amp listed that you could have tried these various opamps in. For instance in my PPA I greatly like the 627s where as my M3 I do not at all...

No, I've also compared it to others in Meta42, Mint and Home-Vibe. Granted though, I don't have an extremely wide experience with opamp comparisons using different amps.

One thing about the Vibe amps, you're likely to hear little coloration other than that of the opamp, so if anything it should give a pretty clear picture of how the opamps actually sound. Maybe I'm oversimplifying things though.

 

[Ikon]

Quote:

Originally Posted by fewtch What... cold? That's not how I hear it at all. Sounds very lively, warm and energetic to these ears. I found the AD8066 to be an extremely boring opamp... dull, plodding and matter-of-fact sounding. Just the opamp one would want for background music.

I think AD86x0 sounds lively, energetic and VERY detailed, but also rather cold and harsh. I can't stand a harsh presentation ... it feels to me like the AD86x0 tries to shove all that detail right down my throat.

But then again we seem to have rather different listening tastes. I have seen you many times praising the DT880 very enthusiastically. I on the other hand prefer the HD580 over it - even though I recognize the superior detail of the DT880, I dislike it's slightly harsher treble enough to dislike this headphone's presentation as a whole.

For my taste, even AD80x6 is not necessarily smooth and warm enough, I often prefer AD823 or AD746 which might very well get you snoring within 2 minutes

What I want to say is: I have no trouble believing that we are both right on this issue - each from his own perpective.

Quote:

Originally Posted by fewtch One thing about the Vibe amps, you're likely to hear little coloration other than that of the opamp, so if anything it should give a pretty clear picture of how the opamps actually sound. Maybe I'm oversimplifying things though.

It is absolutely not easy to define how an op-amp sounds. If you use an unbuffered design, you hear the coloration of an op-amp with a more or less heavily loaded output (-> you also test its driving capabilities). In buffered amps like the META42/MINT, the op-amp's ouput stage has a much easier live and will likely add significantly less coloration to the sound, but then you have to add the coloration through the buffers themselves, of course.

As this is much more about taste than science, I'm just happy that mrdon seems to be more content with the AD8066 than he was with the AD8620

 

[Ikon]

Quote:

Originally Posted by fewtch What... cold? That's not how I hear it at all. Sounds very lively, warm and energetic to these ears. I found the AD8066 to be an extremely boring opamp... dull, plodding and matter-of-fact sounding. Just the opamp one would want for background music.

I think AD86x0 sounds lively, energetic and VERY detailed, but also rather cold and harsh. I can't stand a harsh presentation ... it feels to me like the AD86x0 tries to shove all that detail right down my throat.

But then again we seem to have rather different listening tastes. I have seen you many times praising the DT880 very enthusiastically. I on the other hand prefer the HD580 over it - even though I recognize the superior detail of the DT880, I dislike it's slightly harsher treble enough to dislike this headphone's presentation as a whole.

For my taste, even AD8066 is not necessarily smooth and warm enough, I often prefer AD823 or AD746 which might very well get you snoring within 2 minutes. But talking generally, I think it is quite reasonable to recommend AD8066 to someone who likes the typical ANALOG snap but finds AD8620 a little to cold and lacking in the mids.

What I want to say is: I have no trouble believing that we are both right on this issue - each from his own perpective.

Quote:

Originally Posted by fewtch One thing about the Vibe amps, you're likely to hear little coloration other than that of the opamp, so if anything it should give a pretty clear picture of how the opamps actually sound. Maybe I'm oversimplifying things though.

If you use an unbuffered design, you hear the coloration of an op-amp with a more or less heavily loaded output (-> you test its driving capabilities). In buffered amps like the META42/MINT, the op-amp's ouput stage has a much easier live and will likely add significantly less coloration to the sound, but then you have to add the coloration through the buffers themselves, of course. Which combination colorizes the sound more is not easy to say.

As this is much more about taste than science, I'm just happy that mrdon seems to be more content with the AD8066 than he was with the AD8620