Review: DEQX HDP-3 Preamp/Processor/Active-Crossover

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doug s.

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Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #20 on: 15 Feb 2010, 08:40 pm »
ted, i wanna upgrade to the hdp-3 from my 2.6 (certainly no slouch; mebbe it's different if used as a pre?), and i have no intention of using its preamp capabilities; i am sticking w/my melos pre.

doug s.

BPT

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Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #21 on: 15 Feb 2010, 09:22 pm »
Ted:
At RMAF I had a chance to listen to the HDP-3 through its own analog outs (balanced with the Jensen upgrade) as DAC and preamp vs. using the digital out with Empirical Audio Overdrive Signature DACs as DAC and preamp. The Empiricals were better. Was the difference staggering--no. Was it a difference something I couldn't absolutely live without--no. Was it better--you betcha. While this doesn't exactly answer your question. It should leave you with the impression that the DEQX used as full function is very good. If you have lots of excess cash, the DACs can be bettered and the analog out section can be bettered. YMMV
Chris H.

Tyson

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #22 on: 15 Feb 2010, 11:30 pm »
I guess I need to rephrase my question because I've seemed to miss the mark the first time (prolly cuz I mentioned my disappointing demo five yrs ago; nuff said, it was pilot error).

Ok here goes:  Would any of you who use the DEQX today buy it if you were keeping your current stereo preamp (i.e just as an active speaker crossover).  Tyson, you specifically said you needed to sell your current pre, etc to fund this thing and that's at 50% off MSRP.  Did you try it with the pre?  My assumption is that your current system is sounding better partially cuz the DEQX is significant xover improvement over the modded Behringer; just wondering how much the pre function adds or detracts, especially if sources aren't all pure-digital feeds.  The pre function certainly is part of the DEQX cost.

No worries. To answer your question directly, I would say that if you are going to use the DEQX in fully active mode, with all of the speaker and room correction engaged, then yes it is worth it even if you are keeping your preamp.  The analog inputs (I have on analog source) is quite transparent.  Not as transparent as if "nothing" were there, but then again, what is?

One option you might consider is the version of the DEQX that does not come with the preamp section.  It's less expensive, and might be a better fit for what you are looking to do.  Although I don't see it on their site anymore, I know they made a model like that in the recent past. 

doug s.

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Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #23 on: 15 Feb 2010, 11:49 pm »
One option you might consider is the version of the DEQX that does not come with the preamp section.  It's less expensive, and might be a better fit for what you are looking to do.  Although I don't see it on their site anymore, I know they made a model like that in the recent past.
that's the pdc 2.6; which i have.  afaik, it is still awailable...
http://www.deqx.com/products3.php

doug s.

JoshK

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #24 on: 17 Feb 2010, 01:53 pm »

One option you might consider is the version of the DEQX that does not come with the preamp section.

From a purely engineering point of view, that is a suboptimal solution, as it compromises the signal to noise ratio versus doing the attentuation after the processing.  Of course, some love their tube preamps and won't give them up.


Rubbbq

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #25 on: 18 Feb 2010, 12:29 pm »

I just got these photo's yesterday that i though you would enjoy. Doug at asi-tek.com just finished my Deqx mod. :thumb: He replaced all the op amps with Burson's. He installed a Dexa clock. All new cotton over silver wiring and he made it dual powered; it can run on or off the mains with the battery. :drool: I can't wait to get it back in my system!!! Doug is the man, he does beautiful work:thumb: :thumb: Is there anyone in NYC that has experience with these units? I'm looking for someone to help me re-instal  and tweek it.. Enjoy....







JoshK

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #26 on: 18 Feb 2010, 01:40 pm »
How much where the mods?

I didn't opt for the transformers in my HDP-3 as I have 6 of the transformers which I plan to use on the amp side.  Ideally, transformers at the amp input is a better place to put the tx then on the preamp out, but the difference is minor, and buying 6 tranformers was much cheaper than the upgrade.


sts9fan

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #27 on: 18 Feb 2010, 01:52 pm »
Quote
, transformers at the amp input is a better place to put the tx then on the preamp out, but the difference is minor

What is the difference?

JoshK

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #28 on: 18 Feb 2010, 04:01 pm »
I'd be lying if I said I truely understood why, but I've seen it said many times. 

Rubbbq

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #29 on: 19 Feb 2010, 01:29 pm »
This is a link to what mods were performed and what they cost. I will ask Doug to chime in with some answers.
http://www.asi-tek.com/DEQX_HDP3.html

Also, this is a link to the speakers it will drive....enjoy
http://selahaudio.com/id195.html


JoshK

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #30 on: 25 Feb 2010, 09:21 pm »
Here is part of the answer to the previously raised question. 

Quote
For reasons of limited linear digital range the volume control must be located after the DSP to maximize bit resolution.
  from linkwitzlab.com
http://www.linkwitzlab.com/crossovers.htm

That is not the whole answer though.  It is related to signal to noise maximization, but for some reason I cannot recall how it differs. 

kyrill

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #31 on: 8 Mar 2010, 05:04 pm »
Tyson
you also have in real time listening the possibility to alter tone for bass, mid and highs  when you limit room response to 7 points instead of the 10. those 3 tone controls are part of the remote controller but have a fixed center frequency

rubbbq
be in for a feast. the clock of DEQX is its weakest point, next are the default output caps. with the burson output units ( dc servo f i recall well, so no caps in signal path) on top of yr new clock it will sound as a different class
The very last thing you can do is replace the 15v (+/-) PWS with a Paulhynes pws, which is another jump in transparenvy probably equal or better than the 1000 $ battery supply, but (much) more affordable depending of assembling yourself ( very easy to do)
kyrill

kyrill

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #32 on: 15 Mar 2010, 02:19 pm »
rubbbq
PLZ
what are your impressions of the "new" deqx?

tarquineous

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Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #33 on: 2 Jun 2010, 04:03 pm »
I would be careful not to sell your favorite preamp just because someone else did.

The DEQX pre section may or may not sound better. And think of the cost of more cables and another amp or two. Here's where many people start buying cheap stuff, and end up with just that.

kyrill

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #34 on: 12 Oct 2010, 07:31 pm »
Josh, Rubbbq
What happened?

eternal silence?

I have send my DEQX ( modded pdc2.6 by the factory and regulated analogue pws ) to asi-tek.com for the new .2ps clock and it brought the DEQX to a new level, of focus, transparency and moe musicality by being less an electronic device. The effect equaled or surpassed the change of the electrolytic bypass caps with Sonicap teflon caps. Plz remember the new HD 3 of DEQX still uses 6 electrolytic output caps!!! albeit bypassed with a little red Wima cap There is MUCH more improvement to get by using genuine boutique caps of yr choice. Also the clock in the DEQX is an average non audiophile clock.Still what DEQX does is so good  as Xovers in speakers are the weakest links nowadays. That is why single driver lovers of Fostex and the like swear by it  in spite of lack of bass and audiophile treble. But all freqs in phase like real life..

bbq how does yr modded DEQX sound?  I really want to know :D

kyrill

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #35 on: 1 Feb 2011, 06:09 pm »
Hello rubbbq

How is your DEQX experience after ASI-TEK's mod?
Can you share it with us?

I Surely hope you did'nt die
« Last Edit: 2 Mar 2011, 08:51 pm by kyrill »

glory

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Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #36 on: 28 Dec 2012, 01:36 pm »
He died and went to audio heaven.

wisnon

Re: Review: DEQX HDP-3 Preamp/Processor/Active-Crossover
« Reply #37 on: 28 Dec 2012, 03:08 pm »
Glory, Did you get my email?