Working on the greatest A/B shootout ever..

ok maybe not the greatest but maybe the best for the opamp/capacitor upgrade guys. I have chosen the most likely candidates for usage in the opamp world and those caps that I find are either the most transparent and the most warm out of all AFFORDABLE caps... the Nichicon HE and PW series.

each channel has around 5000uf of rail capacitance total to ensure that the opamps are not starved causing strange artifacts. any gain/bandwidth setting resistors/caps are left as is.

The OPA404 are quad FET input and fairly neutral in color. I could not source the OPA4134 or OPA4604 for this test without going to great lengths to get them or going out of my way to build adaptors for them. Testing with those will come later. only one stage of an OPA404 will be in the signal chain because there will be NO EQ performed on the tracks.

here's a breakdown of the channels to be compared:

5532, tl084 and tl082. nichicon HZ caps. stock channel

Vs.

opa2604, opa404, no caps
opa2604, opa404, nichicon HE
opa2604, opa404, nichicon PW

opa2134, opa404, no caps
opa2134, opa404, nichicon HE
opa2134, opa404, nichicon PW

mc33078, mc33079, no caps (expect DC offset issues due to BJT inputs though these are very low offset)
mc33078, mc33079, nichicon HE
mc33078, mc33079, nichicon PW

opa627, opa404, no caps
opa627, opa404, nichicon HE
opa627, opa404, nichicon PW
(these needed special adaptors)

and finally:

AD825, opa404, no caps
AD825, opa404, Nichicon HE
AD825, opa404, Nichicon PW
(these need special adaptors)

I am finalizing the parts roundup and buildup of adaptors for the special opamps.

I will be testing using Mics with Marik's circuit design with linkwitz modded Panasonic wm61 capsules.. roughly equal to an Earthwork$ mic. For preamp i will be using an SSL9k pre. Tracking will be via an Echo MIA at 44.1/16 straight to disk.

The test subject will be the toughest of all objects to accurately capture and reproduce.. A Sabian HH 13 splash.

I have most of what I need and have some of the initial tests done. I have done no analytical tests whatsoever and will let the tracks speak for themselves.

This has cost a pretty small fortune but should benefit a lot of folks here.

Only thing I ask is.. who has space to keep the tracks online?

Let me know what you think or if I am wasting my time here.

:thumb:

ha, i was planning on a similar test in january.

you are swapping all that in and out of a SSL pre, right?

Im sure you've thought of it, but incase you havent, socket the caps...

might be really cool to also maybe try it with a sm57 or a similar type of mic that many people can relate to.

dave

I was actually going to do it in a pair of console channels so that we could collectively "get" the sound of the opamps and caps. I chose the ssl9k pre for it's cleanliness, same for the mics.

upon thinking further.. it might be worth the effort to build a board with 10 or so unity stages in series with caps between them so we could get an even more true sound of the parts themselves..

Funny, I'm doing this with a friend's Bellari RP503 with the exact same chips!

I have a few zigabytes you can borrow.

Sorry, I watched a Black Sabbath video last night. They were talking about Ozzy's ad in the paper which got him the job. It was

Ozzy Zig Requires Gig!

I guess it worked.

Another very nice sounding opamp that would be nice to test: opa2227/opa4227. IMHO... :grin:
And of course the flagship from analog AD797 that is reputed to be the best audio opamp on chip ever built. (OK it costs a little fortune, just like OPA627 :grin: )

but however: a great idea you had. :thumb: :thumb: :thumb:


Martin

[quote author="Svart"]...either the most transparent and the most warm out of all AFFORDABLE caps... the Nichicon HE and PW series.
[/quote]
Hi, just wondering, which is the transparent and which is the warm?
Have you tried the "audio" caps from nichicon like KZ or FG?
Or are they way too expensive audiophile types?

I'm wondering what would be a safe bet, since I'm stocking up.
Also, any thoughts on mylar or poly-whatevers?
Thanks,
Hejsan

HEs are the transparent ones, PWs are the warm ones.

polypropylenes are big and are closest to perfect as you can get without spending huge money.

polyester/mylar are next and are very good.


teflon, polycarbonate etc are increasingly hard to find in usable values. teflon is by far the most perfect of all.. but try to find them.

I would try the Analog Devices op275, a popular 5532 replacement. I think its a Dave Hill Favorite

May I give a suggestion that will increase the value of the A/B test? Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate some common errors in AB tests, and the comparison job gets easier. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

May I give a suggestion that will increase the value of the A/B test? Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate some common errors in AB tests, and the comparison job gets easier. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

May I give a suggestion that will increase the value of the A/B test? Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate some common errors in AB tests, and the comparison job gets easier. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

May I give a suggestion that will increase the value of the A/B test? Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate some common errors in AB tests, and the comparison job gets easier. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

May I give a suggestion that will increase the value of the A/B test? Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate some common errors in AB tests, and the comparison job gets easier. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

quadrophenia?

[quote author="Svart"]polypropylenes are big and are closest to perfect as you can get without spending huge money.[/quote]
Are there any good brands you can recommend, or does it not matter as much as with electrolytics?
Thanks for the great info.

I hope it's OK if I give a suggestion that will increase the value of the A/B test. Use a mic that you put in front of a loudspeaker. Play back some different sound sources, cymbals, bass instruments etc, and record that through your different varieties of mic preamp. Use the same playback recording for each preamp variety and don't change anything else in the setup between takes, such as the playback level or the mic position. This way, you eliminate all changes in the recordings apart from the ones you want to examine. It also gets easier to compare the resulting sound files as you can easily line them up in your audio app and instantaneous flip through them using the solo function.

Looking forward to hearing the results.

Cheers,
Henrik

Feedback, Henrik? Try turning the keyboard away from the monitor... muuaHAHAHAaaa :twisted:

Mute the mic in going to monitor. Christ.

Hehehe Sorry Henrik, you misunderstood me. I'm referring to the fact that you have posted the same post six times. I can see that you changed the beginning in the post just above here but other than that it's pretty much identical to the five posts on page 1. The joke was that there could be a feedback loop between your computer monitor and keyboard.

I can see how it could be interprited like a comment on your suggestion but it was not. :wink: