Preamp upgrade - any thoughts?

[Rad]

Hi all,

I've been thinking of adding an extra mic pre to my rig but am not sure whether the configuration I have in mind makes sense.

The idea is to add a high-quality preamp to supersede those of the Onyx 400F I'm currently using as a convertor box and feed the new pre's output directly (line-in) to the Onyx convertors. But then I might end up recording via a pre that costs more than the entire interface, convertors and all. Is this really a good idea?

[Rad]

50 views and no replies?!?
Come on people, why did I bother responding to threads and giving advice to people here for the past 2 years? This forum has really gone downhill :eek:

[dpd]

Rad - POOGE the Onyx!

[Rad]

Egh, you don't say where to get the money to afford that?

The point is practical - there's no budget for both a new preamp and a new convertor. It has to be one of the two.

[dpd]

Given the choice, I'd opt for the converters. Preamps color/distort but, IMO, converter distortions are worse offenders to sonic quality than preamps.

Doing a POOGE isn't all that expensive (compared to buying upmarket new) - unless the gear isn't easy to modify; precisely why I still keep my old hi-fi stuff around for monitoring purposes. No SMD stuff to deal with. I could bring it to work where we have all the tools and techs young enough to see the parts (!)

[Rad]

Interesting suggestion, dpd.

My sense was that specifically in the Onyx, the pre's were more of a quality-limiting factor than the ADC's (strangely, it uses the same AKM 5385 convertors as the RME Fireface, possibly with a slightly different front end).
Unless I'm wrong, the conversion quality should be adequate, this is why I was shooting for a preamp in the first place. But I could be wrong.

[dpd]

Interesting suggestion, dpd.

My sense was that specifically in the Onyx, the pre's were more of a quality-limiting factor than the ADC's (strangely, it uses the same AKM 5385 convertors as the RME Fireface, possibly with a slightly different front end).
Unless I'm wrong, the conversion quality should be adequate, this is why I was shooting for a preamp in the first place. But I could be wrong.

Defer to what you hear, then. I thought the Onyx line was supposed to sound pretty good for the price. Sounds like it's time to move up. Anyone do mods for the Onyx yet?

[aitikin]

Just cause the same chip is in there doesn't mean it's the same quality. There's a long thread going on over at the tapeop board that's talking about Black Lion Audio's Sparrow and how it uses the same chip and caps or something as the benchmark. Doesn't mean it's the same unit or anything. Just pointing that detail out.

[Rad]

That's right. The analog pathway preceding the convertor matters, especially in terms of "parasite" inductance / capacitance that shouldn't be there, from what I'm being told by electrical engineers.

That being said, I still claim that the 400F has pretty good sounding AD/DA conversion (We use an RME card in the bigger studio and they sound quite similar). As dpd says, these units are pretty good for the money.

Where I hear the most difference is the preamps, and mainly when comparing to brands like Avalon or UA, (mostly in the amount of detail they catch), but let's agree this is a whole different price class. My idea was to add quality where I need it the most right now, and hopefully, shoot for a convertor later.

[dpd]

Any mixed-signal design gets incredibly tricky to get things right, especially at the bottom end of the dynamic range. One has to understand the power and ground routings and how to separate signal grounds from power grounds, ensure the high-current clock edges driving the converters don't crosstalk into the analog stages and generate aliasing within the converters (sneaking past the anti-aliasing filters). There's the whole issue of keeping low-level, hi-Z circuits away from high-level, low-Z sources. Quality of passive parts, especially capacitors, in circuits processing any kind of transient (e.g. music) waveforms due to the time-dispersive effects of dialectric absorption. The converter ICs themselves can contribute interesting distortions - and they may be sample-rate AND channel 1/2 sensitive (e.g. Apogee's AD-16X vs the Rosetta series). Power supplies are huge sources of sonic imprints in analog circuits. I'm still pretty old-school and prefer my capacitors to be very low-K items (e.g. teflon, polypropylene vs ceramic chips). There's the fundamentals of amplitude and phase / delay response of the circuit. Specs don't tell you squat. Many times a good long comparative peek under the hood can tell you which unit will sound better.

[Rad]

Yo, that's a great posting!
Makes me wonder why I didn't major in engineering. I actually know a audio guy who mods his gear by just replacing the capacitors, but among other things he has a Ph.D. in physics. He claims it makes an audible difference, and I wouldn't be surprised.

But this only deepens the dilemma for non-engineers like myself. Obviously, not being able to tell a good capacitor from a bad one by its looks, I have to resort to brand reputation as guidance. But then some brands are so overrated that it is unclear what to do and how to choose, I think that's my problem right now.

[michaelhoddy]

<EDIT> Stupid post on my part, nothing to see here, move along... </EDIT>

[dpd]

:confused: