[HiFlight]

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif I am running the LTC6241 in LR and LM6172 in Ground and the amp effortlessly drives any of my headphones. .........................snip..................... ...............

This combination of opamps yielded 23 hours of operation before the blue light began blinking. This was in low gain driving my RS-1s and Yuin OK-2s, both at reasonable listening levels.

 

[HeadphoneAddict]

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif This combination of opamps yielded 23 hours of operation before the blue light began blinking. This was in low gain driving my RS-1s and Yuin OK-2s, both at reasonable listening levels.

Nice, with the same LTC6241HV but using the LMH6655 in the ground yielded <7 hours for me, so the LM6172 in ground makes a huge difference.

I am getting 17 hours with the LM6172 in ground but LM4562 in the main amp socket. I guess I need to buy another LTC6241HV from you again. Third time's a charm...

 

[evilmerlin]

Ｗｏｗ! 23hrs is pretty damn good! Will have to give that combo a go.

Edit: Just gave the combo a go, did you notice a rasping sound when the amp is turned off? I get a rasping sound when the USB cable is connected and squelch when it isn't.

 

[HiFlight]

Quote:

Originally Posted by evilmerlin /img/forum/go_quote.gif Ｗｏｗ! 23hrs is pretty damn good! Will have to give that combo a go. Edit: Just gave the combo a go, did you notice a rasping sound when the amp is turned off? I get a rasping sound when the USB cable is connected and squelch when it isn't.

Yes, you will get strange noises as the current in the power supply caps is exhausted when you shut off the amp and still have a signal input. This also happens with an input into the aux input as well.

Nothing to worry about. Easy solution: Stop the input signal before turning off the amp.


Ron

 

[evilmerlin]

Edit: Actually, I still get that sound even with all sources disconnected. Is that still normal?

 

[int]

Sorry for the late answer, but thanks to HeadphoneAddict and HiFlight for the feedback!

 

[HiFlight]

Quote:

Originally Posted by evilmerlin /img/forum/go_quote.gif Edit: Actually, I still get that sound even with all sources disconnected. Is that still normal?

With the opamps I have installed, (LTC6241HV & LM6172) I get a slight whistle sort of sound when I turn off my D2, even with no source. This is with the gain switch in Low. In High gain, this sound disappears.

I would expect the sound to be louder with more sensitive phones or IEMs, but I do think it is normal. I am sure that the magnitude of this sound you are hearing will also be affected by the opamp combination in use.

 

[lucifix]

Hi guys,

Some opamps just arrived and I have difficulty telling the difference in which opamp to use.

For example, for some Intersil opamps, there are two different opamps with different part numbers, and I do not know which to use. They are: ISL55002IB vs ISL55002IBZ

Also, opamps from Linear Technology were
LTC6241HVIS8#PBF
LTC6241HS8
LTC6241HVCS8
LTC6241HVHS8#PBF

Which ones can be used?

They are so confusing!

Thanks.

 

[jma790]

Well, this is a rather old thread, but I don't mind bringing it back again

I received a few opamps from HiFlight, and I am glad that I tried them.
After trying many combos, I have found that the recommendations from many other members aren't wrong at all.
The LTC6241HV/LM6655 combo sounds really good, with great definition across all the spectrum, and a nice warm character (with my Yuin OK1's). Soundstage is really good, with great depth, width and height.
The LM4562/LM6172 is really good too, and bears a better battery life for the D2; I hear a little wider soundstage, but not a big difference, at least with the OK1's. With both combinations bass is really nice and defined, and hits deep.
I also received a THS4032, which I tried in the main socket with the LM6172 in ground, but after a bit of A/B(/C?)-ing I ended up leaving the second combo. For some odd reason the THS4032 doesn't work in the ground socket of my D2 Viper

, and swapping this last combo apparently is another good combination

I hope to try those combos with other headphones to see if my impressions remain unchanged. However, if you have a D2 Viper (or any amp with opamp rolling capability) I think that you own yourself a nice funny time trying which sound is better for you.
Remeber that you can get many opapms from HiFlight, and since he is such a great seller, you can't go wrong dealing with him

 

[int]

to HiFlight: are opamps kits still available?

 

[jamato8]

Quote:

Originally Posted by int /img/forum/go_quote.gif to HiFlight: are opamps kits still available?

I am sure he has some. I would email him.

 

[RAQemUP]

I really enjoy the LM4562/LM6172 (what I am currently listening to) and LM6172/THS4032. ATM I am mainly listening to my Yuin OK1, Senn HD580 and Beyer DT770-250.

I don't have any issues with the THS4032 in the ground. Maybe it is a faulty opamp?

 

[jma790]

Maybe, but it does work with other opamps... I think the faulty one is the LM6172, because it doesn't work when I put it on the LR socket...

 

[sfmatt]

Got some opamps this morning (2xLM6172, 2xLM4562), spent the day switching them around with the stock opamps as well.
Headphones: HD600, DT250/250 and SR80 (just a bit, they're way too bright to my ears).
Music: wav for Classical, Blues and Reggae, 192K for electronica (di.fm minimal, psytrance)
Player: Foobar, application and PC volume 100%

The tests were done with the Viper both used through USB and as an amp only fed by the headphone DAC of my RME 9632.

I've become quite an expert at switching opamps in 2-3 secs... In the end my 2 preferred combos:

Larry's LM4562/LM6172 is pretty surprising coming from stock. Much more in your face but warmer with more body/fullness to the sound. Better soundstage too.
Bass: more and deeper than stock, not as dry though, slightly rounder.
Mids: the most striking change, mids jump at you, they're rich and velvety at the same time. Very enjoyable.
Treble: more extension than stock but a tad harsh at times.

2xLM4562 is more analytical, not as cold as stock but colder than LM4562/LM6172. Soundstage is better than LM4562/LM6172, there's more separation. It's more airy but not thin at all, just not as "meaty" as LM4562/LM6172. Slightly less forward too (but more than stock).
Bass: more bass than LM4562/LM6172, it's dryer but more impactful on electronica. Unsure if it's deeper, both go low.
Mids: they're good, not recessed at all but nothing special either. They blend well with the rest of the spectrum so you don't notice them one way or another, which is good i guess but somewhat of a letdown compared to LM4562/LM6172.
Treble: slightly better extension than LM4562/LM6172 but smoother. No hint of harshness at any time.

In the end, both combos are a marked improvement over stock. It comes down to your personal taste and your headphones match.
I've settled on 2xLM4562 for now, I'll try LM4562/LM6172 again on a longer run later. Unsure about he battery life, LM4562s draw more than LM6172s so we shall see.

Many thanks to everyone on this thread for all their hard work.

 

[sfmatt]

Quick note: took me a while to find that thread, should've been in the portable amps section...