on re-opening the ADA8000; opamps and caps

[indigom]

Greeting All -

I'm new to the forum, and I've been intrigued by the idea of pushing the ada8000 further. Some very lively and interesting discussions there from you guys in that original ADA8000 mod thread.

So I got an ADA8000 yesterday to add some channels to my MOTU 896. And also for possibly improving it's sound.
And from my tests, it seems to need quite allot of help. In the A/B comparison, I mixed a track out through the 8000 as my audio interface has previously used. So the same channels, levels, and cables to the mixer.
The results were less than stunning. The entire song was much lower in level and clarity/space was lacking liveliness.
Back to the hardware..
I'm interested in only improving the D/A stage of the box since I use an apogee for A/D.

Some of you have successfully tried the MC33079 without too much change in the quality, but what other opamps would work in the circuit and what if different caps were used?

I've been considering using Burr Brown, possibly the OPA4604 in the output stages. Now since I'm kind of a newbie to dropping in new chips and other components in circuits, I ask for some suggestions in my choice of parts in this department from the experts. : )

I plan on only changing out 2 channels of opamps at first, testing again, then changing the caps; followed by more tests.

about caps
What are the going opinions on sound improvement concerning Nichicon vs. ELNA Starget in an output stage circuit?

Best,
Jay

 

[gyraf]

Hi Jay,

Welcome to GroupDIY..!

The entire song was much lower in level and clarity/space was lacking liveliness.

To do a comparison, you need to start out by getting the levels right. Comparing two sources of different level is next to impossible! For the series of tests we ran on the '8000, it actually behaved very well..

Could your problems be due to level-wise mismatch to whatever you use to monitor/mix the signals?

Jakob E.

 

[Rossi]

Gyraf is right: you must readjust levels. Different converters have different reference levels. On one converter 0 dBFS can be, say, +9 dBu, on another it can be +22 dBu or maybe only +4 dBu. So these converters will expect different input levels and also produce different output levels. To properly evaluate sound differences, you must compensate level differences very carefully.

 

[indigom]

Guys-
Thanks for the advice on comparison mixes. So tonight I will try to adjust the input trims going to the mixer to match the levels of the MOTU 896 and ADA8000. I'll let you know how it turns out.

Meanwhile, I have some opamps on the way to try out; the LM837 and OPA4134. If these don't work out for the better in the ADA8000, then I have a couple of other pieces that might benefit from them.

Matt from Black Lion Audio had suggested to me opamps from Analog Devices, specifically the AD8066 series. Since these are only dual opamps, I'm having a hard time with my limited knowledge of opamps specs in matching up something similar from AD in a quad SOIC package. Any help/opinions appreciated!

-Jay

 

[Svart]

if you want something that will drop in and offer signifigant improvement in SPECs then try the opa404. i don't remember if they come in soic but i am sure they do. I use the dip version in my console and it sounds very good. the only downside is that they are expensive, around 15-20$ a piece.

:thumb:

 

[cwatkins]

From all my tests, and I use the thing everyday, I really have a hard time faulting it, except for the @%@$% preamp. and I test with the lavry right beside it all day long.

So, can some-one please tell me if this is possible....

I see that I think you can bypass the xlr from the front directly to the converter and it's the same 3 wires... ?

I don't havea picture handy, but it was looking like it...

It was discussed in the other thread, but not like that, I want a total bypass, @$%@$% the preamp or any gain adjustment, give me a ad/da.
I paid $121 new at gc, if the dang thing only does ad/da without that pre-amp it will rock and I bet, and I'm just guessing but I bet the noise
will drop ~10db without that pre in there because the gain will drop 6db.

I'm ranting..

 

[chrissugar]

Hi cwatkins

What kind of test material you use? What amp and speakers? I made some listening tests and we could easyly identify different converters. For example we compared RME DA converters and the DA from Alesis Masterlink and the difference is not subtle. The Masterlink had a much better sound although big differences were heard with acoustic music recorded with two mics. The more electronic the music, you hear less differences.
It is a bit strange because Lavry converters are very good (and the Avocet you mentioned in another thread) so I supose there is something wrong with your setup and/or your test material.

chrissugar

 

[cwatkins]

Ah, kev came to the resque, there is notes on the bypass in that thread, just had to find them..

For reference material I used

a pair of adam monitors 2.5s
the lavry blue into a cranesong avocet
and the avocet d/a
and the behringer

I've tried:
looping them through cubase, analog directly into the avocet and direct into the monitors.
Analog into the avocet is nearly identical so I leave it that way so I can instantly switch.

"It is a bit strange because Lavry converters are very good (and the Avocet you mentioned in another thread) so I supose there is something wrong with your setup and/or your test material. "

Oh yeah, people say that, I know, I heard it for years and I keep looking for my mistakes, but frankly, go try something like a avocet or I hear the m906 works like it too.

Something that lets you switch without moving at all, instantly.

No time nothing.

Then switch back and foreth, over and over and over.

and along with the tests I run with the benchmark, still, I've run the sontec through it, and every other piece of gear.

Material, ok, here's another facinating thing, the only thing I can't seem to stand is classical all day, rap or country.

But, I'll do classic rock, metal, etc. So, I can run, old cat stevens, journey, the latest godsmack with limiter hell, metallica and get a big range of reverb vs punch vs squash.

Ok, I never tried RME converters maybe they were trash, but people said the masterlink had a trashy clock..

I have alot of time on my hands sometimes, I test gear alot. I only recently started making it, but I never in my lifetime though a 125$ behringer converter was going to work like that and I have yet to bypass those @$% pre's but I'm going to do it today.

 

[chrissugar]

[quote author="cwatkins"]
Oh yeah, people say that, I know, I heard it for years and I keep looking for my mistakes, but frankly, go try something like a avocet or I hear the m906 works like it too.
[/quote]
I was talking about the fact that you say there is no significant difference between the Lavry and the Behringer. Not about the difference between Lavry and Avocet. They are in the same class.


This week I had the oportunity to listen to a Boulder DA converter that costs 15000 euros and all I can say it is something absolutely special. I will receive it for some days and do some tests. I ordered the Lavry Blue and hope in some weeks to be here, and will do another comparison.

About the test material, it is not a question of liking or not classical music, it is that it is one of the very few valid test materials that will reveal subtle differences and only if recorded with two, three or four microphones (no multitrack technique). Rock, pop, electro will not reveal subtle differences.

chrissugar

 

[HappyTom]

[quote author="chrissugar"]

This week I had the oportunity to listen to a Boulder DA converter that costs 15000 euros and all I can say it is something absolutely special. I will receive it for some days and do some tests. I ordered the Lavry Blue and hope in some weeks to be here, and will do another comparison.

chrissugar[/quote]

I'm gonna buy that one....
Or a new car, or even a house :green:

 

[chrissugar]

You are right, 15000 for a converter is a lot of money, and I would never spend that amount of money for a DA even if I would be a milionaire.
Interesting is that this converter was bought by a friend of mine and he still pays for it. :grin:
I'm still afraid to take it home, but he insists that he really want to borow it to me and do some tests. I'm very curious about the difference between the Boulder and the Lavry.

chrissugar

 

[daArry]

wooah chris :shock: snap a few pics of the innards if ya can :grin:

 

[chrissugar]

:grin:

chrissugar

 

[cwatkins]

I hooked up the behringer analog again last night, measured voltages,
compared. Still, when you compare it to the avocet they are shockingly similar and all I hear in the lavry is the 5532 vs 604 comparison.

 

[indigom]

So I performed some more mixes through the unit after adjusting input trims, and I agree it sounds very good for what it is and cost.

I haven't changed out any components yet, I'm waiting on an update rework station that will let me handle SMD more appropriately.

Will post results when I get them!

cheers~
Jay

 

[gyraf]

Thanks for the update, Jay..!

Keep us informed..

:thumb:

Jakob E.

 

[synthi]

Hmmm...

What about using those trafos for the line output in the ada8k? The seems to be small to fit inside:
http://www.groupdiy.com/index.php?t...9&start=0&postdays=0&postorder=asc&highlight=
Now if anyone could tell us what impedance and ratio they are...

 

[indigom]

interesting, well there is some space inside the 8k's enclosure for daughterboards that could hold the trannys.


-Jay

 

[synthi]

I received a message from the seller:

He say those are the same as used in the V672, now I`m asking if those are the input or output trafos...
Also he said he only have the papers at the photos for the item, there is a primary 1.5 Ohm and 2 secundaries at 8.5 Ohms (thats 1:5.6)??

Also I just got one package for me

Synthi

 

[gyraf]

there is a primary 1.5 Ohm and 2 secundaries at 8.5 Ohms (thats 1:5.6)??

No. Those are DC resistance ratings. The rather unclear data in the sheets shown seems to indicate rather low inductances, thus best for very-low source impedance drive.

Jakob E.