dAck! mods blow-by-blow

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audioengr

dAck! mods blow-by-blow
« on: 13 Oct 2004, 09:31 pm »
I finally took the dive and bought a dAck! to mod.  It is so popular at this price-point that I thought this has potential.

Initial impressions of the stock dAck!:
1) imaging appears very good but not excellent, likely due to lack of HF extension.  Sounds appear to jump from a black background, but they are not in sharp focus and the HF reflections (air) that should accompany them are not there.
2) like most stock DAC's, lacks ultimate dynamics, particularly at the HF's
3) strange noises through my DC-coupled preamp at power-on - usually this only happens when there is some DC-offset.  Volume control causes no noise, so it must not be too bad - need to measure this
4) some sibilance, but not too bad.  Probably due to stock coupling caps
5) does not really keep me interested or start my toe tapping like my P-3A DAC, but very nice sound for the money.  Piano is too warm to sound live.
6) prediction - should not take much to bring this one up to Turbomod status.  Strategy is to make key mods that minimize the cost yet deliver the maximum improvement.

Planned mods:
1) replace the coupling capacitors
2) improve HF power delivery to analog section
3) add Black Gates where it makes sense
4) improve analog filtering

Results:
TBD

JoshK

dAck! mods blow-by-blow
« Reply #1 on: 13 Oct 2004, 09:41 pm »
Interesting prelim findings.   I got to try it out briefly at the monthly GTG at my pad last year and thought it was damn good for the money.  What struck me was that it had a very liquid and natural midrange.  It seemed a *bit* lacking in ultimate HF extention but ultimately I felt the real short coming was in low end dynamics particularly with orchestral pieces.  Very very easy piece to like though.

There has been a lot of talk about coupling cap upgrade that addresses dynamics written about on this board.  Not sure if that would ultimately deliver on the bottom end goods though as I would imagine you are somewhat limited with a battery PS.  Interested in your findings.  There is just something very natural about non-OS DACs that I like.

Jay S

dAck! mods blow-by-blow
« Reply #2 on: 14 Oct 2004, 05:31 am »
Very interesting initial findings. I am not too familiar with the dACK but I do know that it is a non-oversampling dac, like my Scott Nixon.  If like the Scott Nixon then the HF rolls off at 18 kHZ.  Scott Nixon puts an anti-sinc filter into his current dacs in order to raise top-end response.  My SN does not image and sounstage as well as my Mensa DI/O, perhaps since the modded DI/O had more extended HF extension.  

I'll watch this space closely as I really like the sound of my Scott Nixon and would be interested in a TurboMod upgrade if it can be done relatively cheaply to these non-OS dacs.

audioengr

dAck! mods blow-by-blow
« Reply #3 on: 14 Oct 2004, 04:31 pm »
Quote from: JoshK
Interesting prelim findings.   I got to try it out briefly at the monthly GTG at my pad last year and thought it was damn good for the money.  What struck me was that it had a very liquid and natural midrange.  It seemed a *bit* lacking in ultimate HF extention but ultimately I felt the real short coming was in low end dynamics particularly with orchestral pieces.  Very very easy piece to like though.

There has been a lot of talk about coupling cap upgrade that addresses dynamics written about on this bo ...


The coupling cap upgrade alone will probably not deliver the dynamics of my P-3A.  It will improve the bass tightness and HF focus though.  Dynamics hopefully will be improved with power delivery changes.

audioengr

dAck! mods blow-by-blow
« Reply #4 on: 14 Oct 2004, 04:34 pm »
Quote from: Jay S
Very interesting initial findings. I am not too familiar with the dACK but I do know that it is a non-oversampling dac, like my Scott Nixon.  If like the Scott Nixon then the HF rolls off at 18 kHZ.  Scott Nixon puts an anti-sinc filter into his current dacs in order to raise top-end response.  My SN does not image and sounstage as well as my Mensa DI/O, perhaps since the modded DI/O had more extended HF extension.  

I'll watch this space closely as I really like the sound of my Scott Nixon and would be  ...


I would expect a tube-DAC to image extremely well compared to op-amps.  I have never heard the SN.  The other tube DAC's and tube-output players that I have modded turned-out extremely good.  Here is the latest one:
http://forum.audiogon.com/cgi-bin/frr.pl?rdgtl&1097374526&read&3&4&

ctviggen

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dAck! mods blow-by-blow
« Reply #5 on: 14 Oct 2004, 04:47 pm »
Hey!  That's the unit (Pioneer Elite) that I have.  How much would the mods cost to get my CD player modded?  I'm also on the list for a demo Ack Dack.

ctviggen

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dAck! mods blow-by-blow
« Reply #6 on: 14 Oct 2004, 05:35 pm »
Shucks!  I think I have a 38A, not a 47A.

byteme

dAck! mods blow-by-blow
« Reply #7 on: 14 Oct 2004, 06:29 pm »
Steve does fantastic work, that's a given!  I'm interested to hear the results on the Ack!

Steve,

I'm also still very interested in being the TubeDac guinea pig.  I haven't forgotten about it, just been very busy lately.

Brian.

xero

  • Jr. Member
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ack! and dynamics
« Reply #8 on: 14 Oct 2004, 07:55 pm »
hello steve

thanks for refering me to this audiocircle link.  the idea that this unit
can become a world beater is just up my alley.  i think that it is important
to have a discription of the system that the ack is now being voiced on.
so that i can begin to make more accurate comparisons to how our systems may respond to the improvements.

as i read some of the discriptions atributed to the ack i reflected on the sound that i am currently getting.  right now the sound is the most realistic open sound that i have heard in my room.  the sound may not be as layered as i would like but i think that that is partially due to how far the speakers are from the front wall (4.5ft)

i am quite interested in increasing the 3d space that is already there.  regarding the bass mine might be consider a little soft and i would like
to increase the impact.  but i would say that because i am running a
bent audio passive into a nelson pass aleph 5 ( which does not have
much gain)  might be part of it.

my system

bow technologies zz8
ack! dac
bent audio tvc
aleph 5
vienna acoustics mahler

thanks for listening and let me know how far off base my head may be.

e

audioengr

dAck! mods blow-by-blow
« Reply #9 on: 15 Oct 2004, 05:09 am »
Quote from: ctviggen
Hey!  That's the unit (Pioneer Elite) that I have.  How much would the mods cost to get my CD player modded?  I'm also on the list for a demo Ack Dack.


The Pioneer DV-47A transport mods are $500, $230 additional for the Jensen 4-pole cap, power resistor and relay (required) and $550 for the SuperTurboclock2.  Its on the component mods page of my website:
http://www.empiricalaudio.com

If you want analog/DAC mods as well, these are in the $650-750 range, if you have the stock output stage.

Steve N.

audioengr

Re: ack! and dynamics
« Reply #10 on: 15 Oct 2004, 05:31 am »
Quote from: xero
hello steve

thanks for refering me to this audiocircle link.  the idea that this unit
can become a world beater is just up my alley.  i think that it is important
to have a discription of the system that the ack is now being voiced on.
so that i can begin to make more accurate comparisons to how our systems may respond to the improvements.

as i read some of the discriptions atributed to the ack i reflected on the sound that i am currently getting.  right now the sound is the most realistic open sou ...


Your class A amp is likely giving you the open sound.  However most stock components are lacking in transient response.  This is why you dont have the slam factor and bass tightness.  The dAck! has pretty good transient response stock, except at the high frequencies.  Your passive linestage is probably the biggest factor that will sap the dynamics out of your system.  Most amps need some drive to really get dynamic.  Your transport also needs mods to focus properly.  See these papers I wrote:
http://www.positive-feedback.com/Issue15/modsnugent.htm
http://www.positive-feedback.com/Issue14/spdif.htm

My system is described on the "about EA" page of my website.

xero

  • Jr. Member
  • Posts: 30
ack! passive and dymanics
« Reply #11 on: 15 Oct 2004, 06:17 am »
steve

i have had resistor based passives before and would agree that they have lacked in dynamics.  the passive that i currently have uses
transformers and the dynamics are here in spades.

would you be so kind to elaborate as to the system you are using to
voice the ack?  while i may not have heard all of the things in your
system it is good for me to know what the basline is.

thanks again
e

xero

  • Jr. Member
  • Posts: 30
i take that back
« Reply #12 on: 15 Oct 2004, 06:25 am »
steve

i partially read your post i will look on you site regarding your system.

sorry
e

audioengr

dAck! mods blow-by-blow
« Reply #13 on: 17 Oct 2004, 05:33 pm »
A look inside reveals a few interesting things:

1) input is coupled with capacitors - I will change this to transformer
2) he has done a decent job of power delivery to the receiver chip - I noticed right away the SMT caps on the pins.  This is one reason that it sounds good stock
3) power delivery can be improved to op-amps and the layout will make this very easy to accomplish
4) power delivery can be improved to the DAC chip as well
5) Filtering uses dipped polystyrenes - not bad, but I can improve on them
6) I will not change the op-amps initially
7) looks like there is room for the Multicap RTX coupling caps - barely
8 ) common ground return from both RCA output connectors

I am very optimistic that this unit can rate a Turbomod status after mods.

davejcb

dAck! mods blow-by-blow
« Reply #14 on: 17 Oct 2004, 11:49 pm »
Quote from: audioengr
I am very optimistic that this unit can rate a Turbomod status after mods.


What exactly constitutes or defines a "Turbomod"?

audioengr

dAck! mods blow-by-blow
« Reply #15 on: 18 Oct 2004, 02:55 am »
Quote from: davejcb
Quote from: audioengr
I am very optimistic that this unit can rate a Turbomod status after mods.


What exactly constitutes or defines a "Turbomod"?


It must approach or match the performance of my reference component.

audioengr

dAck! mods blow-by-blow
« Reply #16 on: 20 Oct 2004, 07:49 pm »
Update:

Mods are complete and I have started listening.  Here are initial observations:

1) best cymbols I have ever heard from a DAC.
2) dynamics are greatly improved, top to bottom, but not quite as good as the P-3A DAC - probably because I didn't change the stock op-amps
3) Bass is good, but not as thumpy or tight as the P-3A DAC - may improve with break-in
4) Piano does not have the "bite" of the P-3A, but is very clear and sibilant-free now - every note is distinct
5) really sounds like music

It needs some break-in for the coupling caps, so I will run it for a few days and then report back.  Sounding like a Turbomod already.

Double Ugly

dAck! mods blow-by-blow
« Reply #17 on: 20 Oct 2004, 08:10 pm »
Quote from: audioengr
3) Bass is good, but not as thumpy or tight as the P-3A DAC - may improve with break-in ...

What is a "thumpy" bass?

DU

ctviggen

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dAck! mods blow-by-blow
« Reply #18 on: 20 Oct 2004, 08:39 pm »
What would these mods cost (approximately)?  I'm going tonight to pick up my test Ack Dack.  After I compare it with some equipment here, I'll decide whether to keep it or not.  I'll likely set up the comparison as follows:  I'll compare my ShengYa CDP with using my Pioneer Elite DVD player as transport to the Ack Dack, as I've compared the ShengYa CDP with the PE DVD as transport to my Proceed AVP (as D/A) and they were basically the same.  I can use the same interconnects for both, and I can do my first-ever interconnect test.

audioengr

dAck! mods blow-by-blow
« Reply #19 on: 21 Oct 2004, 01:56 am »
Quote from: ctviggen
What would these mods cost (approximately)?  I'm going tonight to pick up my test Ack Dack.  After I compare it with some equipment here, I'll decide whether to keep it or not.  I'll likely set up the comparison as follows:  I'll compare my ShengYa CDP with using my Pioneer Elite DVD player as transport to the Ack Dack, as I've compared the ShengYa CDP with the PE DVD as transport to my Proceed AVP (as D/A) and they were basically the same.  I can use the same interconnects for both, and I can do my first-ever interconnect test.


I  think the mod will be in the $500 range.  If you are the first guinea pig, then you usually get the lowest price.