DOA comparison

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abbey road d enfer said:
I don't hear any difference.
I guess if there are, they are buried by the transformer's response and by the mp3 encoding (and by my aging ears).

It's funny. For years I've read and heard many going on at great length about specific versions of opamps and how desirable they are.

I hear basically nothing in my vintage vs new 2520's. Or, nothing worth shaking a stick at...

Anyway, I concur.
 
desol said:
It's funny. For years I've read and heard many going on at great length about specific versions of opamps and how desirable they are.

I hear basically nothing in my vintage vs new 2520's. Or, nothing worth shaking a stick at...

Anyway, I concur.
That's because, contrary to monolithic IC's, where process have evolved considerably over the years, discrete semiconductors have a less distinct evolution. A BC109 of current date is not much different than a BC109 of yesteryear; the latter needed to be selected, today they are run-of-the-mill.
 
Thanks for doing this comparison, I always enjoy these...  Here's what I hear:

GAR - My favorite on this piece of music... slightly round, warm, adds a bit of vintage tone...
APP - Similar to GAR  but seems to have a bit of a boost somewhere around 3 K ish.... the vocals seems to cut more, but for this piece id still choose the GAR
AC Sound - Sounds fine, a little bigger than the 5534s & more 3D but has less 'character' than the GAR or APP
5534s - Both sound thinner than the rest to me, with the TI being the thinnest...

For this piece of music, I would absolutely choose the GAR...  but thats because I think it wants to sound somewhat 'vintage'...

Thanks again for the comparison, & good job on a very nice sounding track!


After listening again, I am realizing that I think I'm hearing a touch of compression like character on the GAR that I am digging...  it seems to be smooshing things together just a touch, which Im liking on this piece of music.
 
Interesting, keep it coming!


I did more tests, this time with the CAPI 2-ACA on the summing bus. What I ended up with was again the TI NE5534 in the summing position, but with the GAR1731 in the booster slot.

In the summing position the GAR1731 takes away low end as well as high end but adds a nice beef to the lower mids and a finished quality to the higher mids, but also some grain to the high end. Ultimately I again prefered the 5534 for summing, it's really full, open and neutral.

Surprisingly, in the booster the 1731 had better low and high end and a more cohesive overall sound than the 5534, which sounded kind of worn out. Maybe a problem of marginal stability?
 
living sounds said:
Interesting, keep it coming!


I did more tests, this time with the CAPI 2-ACA on the summing bus. What I ended up with was again the TI NE5534 in the summing position, but with the GAR1731 in the booster slot.

In the summing position the GAR1731 takes away low end as well as high end but adds a nice beef to the lower mids and a finished quality to the higher mids, but also some grain to the high end. Ultimately I again prefered the 5534 for summing, it's really full, open and neutral.

Surprisingly, in the booster the 1731 had better low and high end and a more cohesive overall sound than the 5534, which sounded kind of worn out. Maybe a problem of marginal stability?
I've probably suggested this before, but with a console you can probably set up two channels in parallel and null them from each other to empirically isolate what the difference is. This won't tell you which one is different, but you can probably determine that from some additional comparisons. 

Or make bench measurements.

JR
 
JohnRoberts said:
I've probably suggested this before, but with a console you can probably set up two channels in parallel and null them from each other to empirically isolate what the difference is. This won't tell you which one is different, but you can probably determine that from some additional comparisons. 

Or make bench measurements.

JR


Yes, I always record a file, nulling them is always enlightening. I do measurements, too, but they're of limited help because the transformers in the signal path contribute quite a lot of distortion.
 
Few years ago i really liked the john burdick 2520...but i recently compared it vs a gar2520.
GAr2520 are great!
 
living sounds said:
Interesting, keep it coming!


I did more tests, this time with the CAPI 2-ACA on the summing bus. What I ended up with was again the TI NE5534 in the summing position, but with the GAR1731 in the booster slot.

In the summing position the GAR1731 takes away low end as well as high end but adds a nice beef to the lower mids and a finished quality to the higher mids, but also some grain to the high end. Ultimately I again prefered the 5534 for summing, it's really full, open and neutral.

Surprisingly, in the booster the 1731 had better low and high end and a more cohesive overall sound than the 5534, which sounded kind of worn out. Maybe a problem of marginal stability?

Try my gar918BC in the summing position.  My favorite.  :)
Also Hairball's 990 is great there too!
Both DOAs are open and neutral and not quite as thin as the 5534.

GARY
 
gar381 said:
Try my gar918BC in the summing position.  My favorite.  :)
Also Hairball's 990 is great there too!
Both DOAs are open and neutral and not quite as thin as the 5534.

GARY

Thanks Gary, just ordered a few. I will report back after I built and tried them.  :D
 
Okay, finally got them (from the customs office  ::) ), built them, tried them - love them! The gar918BC  is now officially my favourite op amp for the summing position (still have to try it for anything else).

The difference to the 5534 (BB2521 DOA) is very obvious and I expected a lot less. A veil is lifted from the high- and midrange, a fast low end punch is added (or not taken away).  Clarity is all there, unlike all the other DOAs I've tried there's no midrange clutter, hyped top end, added "texture"(=grain), transient restriction etc. noticeable. Very nice!

Thank you for this great projec, Gary!

Any other recommended uses? I will try preamp and fader buffer next.

BTW, I used BD139/BD140 instead of the MJE172/182 in my built.

 
living sounds said:
Okay, finally got them (from the customs office  ::) ), built them, tried them - love them! The gar918BC  is now officially my favourite op amp for the summing position (still have to try it for anything else).

The difference to the 5534 (BB2521 DOA) is very obvious and I expected a lot less. A veil is lifted from the high- and midrange, a fast low end punch is added (or not taken away).  Clarity is all there, unlike all the other DOAs I've tried there's no midrange clutter, hyped top end, added "texture"(=grain), transient restriction etc. noticeable. Very nice!

Thank you for this great projec, Gary!

Any other recommended uses? I will try preamp and fader buffer next.

BTW, I used BD139/BD140 instead of the MJE172/182 in my built.

I really like these for Balanced receivers.

Also monkeyxx tells me that he likes these in
312 style pres for guitar.

BTW... Thanks for the BD139/140 info.

GARY
 
hmm.. the old links are not working anymore..

I would like to hear this opamps in this Position !

i did my own opamp test recording digital drums from my machinedrum some years ago  looking for the most softest to cut some of the 12 bit transients from the machinedrum . I always recorded the same 4 tracks (bd, sn, perc and hats) through 4 vp28 , each filled with
the same opamps ( quite a work to  change 8 opamps each time  :)  )
AD/DA was Prism Orpheus so i think thats good enough to easy spot the differences.
While just listening during recording i heared lots of differences ( i thought  ).
But when lined up in the DAW without break between and looking away while playing i could almost not spot  when the
opamps changed..

there was a small change which got stronger when hearing all 4 tracks together but not as "lifting the curtain " - what i thought while recording.
I did know of the power of blind Tests before ,but getting so fooled was quite enlightend for me !


I tested gar1731, gar2520, APP902 and reddots.

I liked gar2520 and APP902 best in this application,
so i have a pair of vp28 with APP and one other pair with gar2520 in my rack.
The vp28 itself for sure has more impact on tone than the opamps i would say .
now that i forgot which pair is which i just grab one and record !
 
They are here:

https://www.dropbox.com/s/1j39yvgf422e31c/ACsound_2520.mp3?dl=0
https://www.dropbox.com/s/526comue0hitfs0/APP992.mp3?dl=0
https://www.dropbox.com/s/1cqgbi06a2hy8do/BB2521_5534_Phillips.mp3?dl=0
https://www.dropbox.com/s/luf2xc3rdrdndm2/BB2521_5534_TI.mp3?dl=0
https://www.dropbox.com/s/ol7trfnawkij9sa/GAR1731.mp3?dl=0



In the end I still wasn't happy with any DIY op amp for the summing position, so I bought the Melcor clones from Scott Liebers, he calls them SL-1731. These are in a class of their own, transparent high end with a big punchy bass, none of the grain the GAR1731 produces. They're not on his website, but you can still order them for about the same price as his 2520 clones.  Pricier than DIY, but well worth it IMHO.
 

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