[NelsonVandal]

Just switched OPA2134 for LM4562 and 2xLMH6642 for 2xLMH6654 from National. I was really going to try AD8620 after Andrea's recommendations, but it's delayed from Analog. I'm going to let it burn-in for a while now. My first impression is that the congested Xenos-sound seems to be gone. The highs are clearer and more open, and not synthetic like the LM6171 seems to be. The mid is still a bit prominent though but more transparent and intimate. I can't really evaluate the bass because it's the weak part in my old cans, but it's definately not worse. I'm going to try it out with my Senn's later. It plays really well with my modded Philips SHP895 in a way the original Xenos never did. I might even regret bying those Sennheiser HD650. Yeah if did this mod a month ago, I wouldn't have bought them.

I'm smiling right now!

Is there anybody out there who has tried LM4562 yet? How does it compare to AD8620?

 

[chris_ah1]

the 8610 does draw less power though.....spec wise the 6654 does seem better except in terms of input current bias.

 

[Andrea]

Congrats on your mod!

Could you please develop a bit about the way the modified amp sounds with the HD650 (after some burn in if you prefer). What is it that you don't entirely like, is it a matter of balance or...?

 

[Andrea]

I've just put the board with the AD8620BR and the LMH6654's back in the amp. I want to evaluate it less hastily... Probably it'll stay in anyway, though

 

[Andrea]

Meaning... I want to decide what the official configuration for my next 0HA-REP should be and go ahead without looking back.

 

[NelsonVandal]

I'm still sure the LM4562 lets my SHP895 shine. The sound is so alive now compared to the dull sound of OPA2134. The treble is clean, sparkling, full of details. So is the mid. It's very airy, I would even call it ethereal. There's a great separation of instruments. It gives the impression of very low distortion, and the noise level seems to be lower. The bass isn't quite as good, not really focused - a bit "wet". I don't think the sound is natural. This is how I recall the sound signature of my valve amplifiers back in the 80's - a bit wet, spatious, sparkling and fun. Like Fuji-chrome or Kodacolor compared to a natural colour-scale. It goes hand in hand with the Philips cans.

The sound resembles that of my MP-amp with LM6171, but better. Is this the National house sound? I think it matches the description of the sound of Go-Vibe 5 as well (I've never heard it myself). It is a very fun and musical sound. With the OPA2134 i listened to the faults, now I listen to the songs.

The quality of Sennheiser HD650 is it's musical, down-to-earth-sound. Focused mids, clear and true highs and warm but yet tight bass. Mono sounds from the middle of your head and stereo sounds wide enough. With the LM4562 nothing really plays right in the middle. Everything is a bit airy and larger than life. The treble is a bit too crisp. It kind of ruins the quality of these cans. Yet it's much better than OPA2134, I'm never going back to that.

I will get my AD8620 thursday, and I'll probably exchange the chips this weekend. I've decided the Senns will be my main cans, otherwise I think I would have been happy with the LM chip.

 

[Andrea]

I've got what you'll find to be a very singular theory...

I try to match chips so as to achieve the most assortment of numbers possible, avoiding excessive repetition. I realized that each number seems to have a precise sonic correspondent (ever heard of numerology?) ...really.

Believe it or not.

Based on this theory, there's a little too much repetition in the chips you chose...you have a "24455666" ...which would suggest a certain lack of complementariness between the LM4562 and the LMH6654. Take it as you will.

 

[NelsonVandal]

OK, then I really should try the 8397 out. I'm sure it will go well with 650, but then again to many 8's and 9's to go with 895. I think it'll be the 8620 anyhow - it must be the best compromise.

 

[Andrea]

Quote:

Originally Posted by NelsonVandal /img/forum/go_quote.gif OK, then I really should try the 8397 out. I'm sure it will go well with 650, but then again to many 8's and 9's to go with 895. I think it'll be the 8620 anyhow - it must be the best compromise.

You're already starting to sound like me.

 

[Andrea]

Finally I managed to take the time to sit and listen to the AD8620/LMH6654, together with the other recent mods (see sig below).


Sounds wonderous! Awesomely natural and neutral with my HD650 & for my ears. Meaning that besides a fine balance, timbre is beautiful too. Vocals sound splendidly, smooth, focused, intimate and full of subtleties. The whole soundscape is very spacious and clear. Bass & treble are extremely resolved and controlled.

Comparing to the other board with the AD823/AD8397 chips, this one is more evenly balanced throughout. It sounds less fun (but still fun enough) and more accurate. The bass is still highly dynamic, if not quite so thunderous. Vocals sound more 'true' to me through the AD8620/LMH6654.

 

[Andrea]

The "fun boost" alternative would be AD823/LMH6654, which will have a more impactful bass & wetter midbass.

 

[NelsonVandal]

I'm going for the AD8620 tonight (I'm not touching the LMH6654's). If it's not "fun" enough, I might be going for the 823. Thank's for your comments.

 

[Andrea]

You're welcome! Please report...

 

[chris_ah1]

Quote:

Originally Posted by Andrea /img/forum/go_quote.gif Finally I managed to take the time to sit and listen to the AD8620/LMH6654, together with the other recent mods (see sig below). Sounds wonderous! Awesomely natural and neutral with my HD650 & for my ears. Meaning that besides a fine balance, timbre is beautiful too. Vocals sound splendidly, smooth, focused, intimate and full of subtleties. The whole soundscape is very spacious and clear. Bass & treble are extremely resolved and controlled. Comparing to the other board with the AD823/AD8397 chips, this one is more evenly balanced throughout. It sounds less fun (but still fun enough) and more accurate. The bass is still highly dynamic, if not quite so thunderous. Vocals sound more 'true' to me through the AD8620/LMH6654.

Damn you, damn you damn you!!! Now you've made me want to ditch the go vibe for the xenos with AD8620.........or dump it all and spend the $234 on a re-released portaphile v2^2!!!

And I'm saying this despite not even having the govibe yet!!!

 

[NelsonVandal]

The AD8620 is now in my Xenos. Threre's a distintive different sound now. It plays much better with my Senns but slightly worse with my Philips.

With the Senns: The bass and mids are clearer more focused and "truer", a bit drier. Most of the time the vocals are straight in the middle (like they should be). It really brings out the best of the Senns mids, and that's goood! The treble is a bit more coarse, and a little bit sibilant. It's not as spacious as LM4562 (wich is probably over-spacious), but much more open than OPA2134. It surprised me that the noise level is much lower, it's barely audible. All amps I've used so far have brought in front a nasty 3 kHz resonace wich is the major fault in HD650 (due to it's horn construction I think). With AD8620 it seems attenuated. The chip isn't totally neutral. I can hear it's distinctive character listening to different songs/CD's. All in all there's great synergy now between the amp and the 650's. If there was just a little bit less sibilance and shiny treble it would have been perfect.

With my Philips it's not as fun to listen to as with LM4562, or my cheap MP-amp with LM6171. And it's too sibilant as well. Nothing is better exept the noise level. I didn't believe in this synergy-thing before, but now I'm convinced.

Andrea, do you think the fun-factor is from the AD823 or the AD8397 as buffers?

Wich combination do you refer to when you say "Sounds wonderous! Awesomely natural and neutral with my HD650 & for my ears. Meaning that besides a fine balance, timbre is beautiful too. Vocals sound splendidly, smooth, focused, intimate and full of subtleties. The whole soundscape is very spacious and clear. Bass & treble are extremely resolved and controlled."?