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Forum Home > General Discussion > DIY question for the membership

Peete
Member
Posts: 11

Would you guys like me to post the Audio-gd MAX Mod series in the DIY section ?  It'll be a HUGE single thread and it will take me the better part of a week or two to complete writing it (have all the pics to go with the details,BOM etc). I realize the RE1 is no longer made but the mod more or less translates with slight differences between the RE7 and the new NFB7 series dacs. I have to study the NFB 7 in detail before pointing out any differences (RE7 as well) but for ther most part the MAX mod on the A-gd REF series of dacs deals with the various power supplies used in that gear which doesn't change all that much from the RE1 .


 The Phoenix mod does have relevance (as does the forthcoming CD7 transport MAX mod) since these are current production items (the CD7 and the CD7SE/CD7 FV are almost identiucal under the hood). My thoughts are to post the entire mod as a "system" upgrade thread rather than a series of singular specific parts of the whole. It'll make it easier to source the details if anyone decides to try these mods out.


What are your thoughts/suggestions gents ?


Peete.



November 6, 2010 at 5:38 PM Flag Quote & Reply

rosgr63
Moderator
Posts: 141

That's an excellent idea!

We are really looking forward to your thread.

It's going to take a lot of time and effort and it's much appreciated.

--

There are few pleasures as simple, and wonderful as music - Craig Uthus

November 6, 2010 at 6:24 PM Flag Quote & Reply

Peete
Member
Posts: 11

Right...I'll get cracking on it this evening (after the Toronto Maple Leaf game is over) :D



Peete.

November 6, 2010 at 7:38 PM Flag Quote & Reply

rosgr63
Moderator
Posts: 141

Peete, i can't see the photo.

Enjoy the game!

--

There are few pleasures as simple, and wonderful as music - Craig Uthus

November 6, 2010 at 7:41 PM Flag Quote & Reply

Peete
Member
Posts: 11

I'm having trouble with the pics ...are there any size restrictions or other notables (I use photobucket) I should be aware of ?

November 6, 2010 at 7:52 PM Flag Quote & Reply

Peete
Member
Posts: 11



Ok I got it....here is a teaser pic of the DSP-1 module mod...it's a V1 pcb (DSP micro code rev).


Peete.

November 6, 2010 at 8:04 PM Flag Quote & Reply

Amine Slimani
Site Owner
Posts: 162

Peete,


First, glad to see you have joined Tweak-Fi.


Regarding your "MAX mod trhread", I believe it would be extremely helpful and interesting for people to have all that data in a single thread.


Regarding the teaser picture, I am curisous about the little blue capacitors you added which aren't in my DSP1 boards.

BTW, if you ever get a chance try the DSP1 V5: I have just put it in my dac19dsp 2 days and I am totally astonished by the difference it made in comparison to the DSP1 V3. I was told by Kingwa it still needs burn-in but even after a few hours, the change is what you would expect from a change in DAC or transport.


I can hardly imaging how a fully MAX modded Ref1/7 would sound like :)

November 26, 2010 at 11:28 AM Flag Quote & Reply

deep sounds
Member
Posts: 112

Peete,

is it possible to mod the DSP V3 into a V5.

 

It looks like you've by-passed the vertical caps - I think I recoginse the blue b/pass caps.

November 28, 2010 at 9:51 AM Flag Quote & Reply

Amine Slimani
Site Owner
Posts: 162

deep sounds at November 28, 2010 at 9:51 AM

Peete,

is it possible to mod the DSP V3 into a V5.

 

It looks like you've by-passed the vertical caps - I think I recoginse the blue b/pass caps.

I believe that the move from V3 to V5 is mainly software related (on the Altera Cyclone chip). So I doubt that anyone besides Audio-gd can make that upgrade.


Though, the mods Peete is suggesting (replacing the capacitors, resistors... with better ones) will undoubtedly reduce the jitter in the chip and improve the overall performance.



November 29, 2010 at 10:02 AM Flag Quote & Reply

deep sounds
Member
Posts: 112

If the Wimas have an effect on sound o/put, replacing them will definately be a big upgrade - let's wait and see.

 

I have emailed Audio-GD  about replacing V3 with V5 - let's see what the answer is.

November 29, 2010 at 10:25 AM Flag Quote & Reply

sayh
Member
Posts: 1

Looking forward to all the mods. keep them posted soon. And thats a innovative way to mount those MKPs neat for the DSP1. Are the MKPs leads sleeved, going to the caps?

 

November 30, 2010 at 6:16 AM Flag Quote & Reply

jkeny
Member
Posts: 27

Seeing as we are talking about this board, can anyone tell me why Audio-gd use film caps(red Wima's) as bypass caps for the chip - they would seem to me to be unsuited to the task when good quality COG ceramic would seem to be much better -lower ESR, etc?

--

MOT: HiFace USB Transport Modifications & Ancillaries 

Regards

John

November 30, 2010 at 7:26 AM Flag Quote & Reply

Amine Slimani
Site Owner
Posts: 162

jkeny at November 30, 2010 at 7:26 AM

Seeing as we are talking about this board, can anyone tell me why Audio-gd use film caps(red Wima's) as bypass caps for the chip - they would seem to me to be unsuited to the task when good quality COG ceramic would seem to be much better -lower ESR, etc?

My guess is that price is a concern.

That is why mods like Peete's are very interesting for those who want to get the absolute best from audio-gd's products. I wonder what Peete thinks about replacing the Wima caps with something else (since he appears to have let them untouched in his mods)?


I wish that some day Audio-gd will offer a MAX series based on Peete's mods. That way non DIY skilled (like me) could get to listen to those upgraded products.

November 30, 2010 at 1:54 PM Flag Quote & Reply

deep sounds
Member
Posts: 112

jkeny,

 my thoughts exactly. It's not only price but size. Norbert Lehman started off with a brilliantly designed phono stage and then used very cheap components, which hid what is possible to acheive with that phono stage.

 

I started off by changing a 2.2uF Wima with an ERSE cap and the difference was so good. Others have commented on these caps.

 

I now have a total dislike of Wimas, those used are exactly the same as Lehman used - yes very small/shorter signal paths yes but they are lifeless, just like Solens.

 

It does seem that the Chinese have an obsession with using Wimas amd Solens.

 

I really am looking forward to getting the lid off the DAC 19, I shall of course listen as is to start with . Am I wrong in thinking that the individual PCBs are easy to remove, I ask because track lifting and other problems from constantly removing PCBs are not funny, I have learned to my cost - only one component change at a time or you lose all reference points.

November 30, 2010 at 6:37 PM Flag Quote & Reply

deep sounds
Member
Posts: 112

Just posted on the DAC 19 Headfi thread - Audio-GD are'nt doing any more swaps for previous DSP-1s.

 

I have to say that when a company changes an important part of a DAC, 3 times in about 8 months they are going to lose all credibility.

 

I reckon it makes this thread more important than ever.

December 3, 2010 at 6:17 AM Flag Quote & Reply

jkeny
Member
Posts: 27

Sorry guys, you misunderstood me, I'm not talking about Wima caps being bad in signal passing duties - they are being used in PS bypass duties on a high speed DSP here. In this role they are not suited. I haven't looked but I'm sure Altera recommend smd ceramic (probably COG) capacitors & the low ESR of these are best suited to deal with the speed of this DSP. In the same vein, I'm not sure that bypassing electro caps with film caps in the PS will have any beneficial effect.  

 

--

MOT: HiFace USB Transport Modifications & Ancillaries 

Regards

John

December 3, 2010 at 1:29 PM Flag Quote & Reply

deep sounds
Member
Posts: 112

jkeny,

 they are bad but your point is a very good one - can you give more precise details on these ceramic caps so we can check them out.

 

I don't know that Peetes by pass caps are film. I need to rummage in my spares box but I think those caps are higly rated for digital work but I could be wrong.

December 3, 2010 at 2:33 PM Flag Quote & Reply

jkeny
Member
Posts: 27

What do you need to know? I'm no expert but I have co-designed a Sabre DAC board with ACKO (the AckoDac on DIY audio) & learned a bit about layout & de-coupling.


The goal, with high speed chips, is to use de-coupling capacitors that are effective at the speeds the chip operates at. Low esr ceramic SMD caps as close to the PS pin is recommended. COG is a particularly stable cap that doesn't change capacitance with temperature.


At high frequencies the distance from the pin to the capacitor is important because of inductance - that is why leaded caps are not used - the leads have too much inductance. Have a read of this 

Or here 


Look inside any computer at the motherboard - do you see any film capacitors being used in the PS de-coupling role?

--

MOT: HiFace USB Transport Modifications & Ancillaries 

Regards

John

December 3, 2010 at 10:20 PM Flag Quote & Reply

deep sounds
Member
Posts: 112

jkeny,

very good input there - the White Electronics explanation was very good indeed. To be fair to Audio-GD the leads on the Wimas are very short indeed.

 

I could'nt see any individual prices quoted only for 100 , so am I right in assuming these caps are not expensive - looks like an opp. for a group buy?

December 4, 2010 at 11:12 AM Flag Quote & Reply

jkeny
Member
Posts: 27

deep sounds at December 4, 2010 at 11:12 AM

jkeny,

very good input there - the White Electronics explanation was very good indeed. To be fair to Audio-GD the leads on the Wimas are very short indeed.

 

I could'nt see any individual prices quoted only for 100 , so am I right in assuming these caps are not expensive - looks like an opp. for a group buy?

Yes, the Wima leads are short but add that to the dimension s of  the caps & it is large compared to the SMD caps. At these speeds (500MHz) it's all about the loop distance between PS & ground. You can see that it is about 5 or 6 times more for the Wima cap compared to an SMD cap. This may not translate into significant sonic improvement but it is the recommended way to do things AFAIK.


Don't get too hung up on using COG caps, probably any smd cap would do but you do have the issue of trying to fit SMD caps where there was once Wima leaded caps.

--

MOT: HiFace USB Transport Modifications & Ancillaries 

Regards

John

December 4, 2010 at 3:20 PM Flag Quote & Reply

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