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Modifying the Subbu V3 DAC

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M

Mull3t

Member
Joined 2012
Since this is the modification thread for the Subbu v3. Is there any chance of modifying the board to take i2s? I know with the old board -- v2.6 (I think this is the version) it was possible. I'm not expecting external clocking, but at least i2s input. Otherwise, I'm on the hunt for another DIY DAC project to utilize my Subbu v3 PS with. Not Curryman 9023. Already done that.
 
jean-paul

jean-paul

Disabled Account
Joined 2002
curryman said:
curryman DAC is much better of course :D

just kidding!
Actually its hard to compare those DACs due to the completely different setup:
SPDIF vs. I2S
no Buffer vs JG Buffer
...
most important: I am heavily biased :eek:

kind regards, Daniel
Click to expand...

OK now without bias then. As I am totally unbiased (better is better whatever it is made of or who made it) I will start :

- Currymans DAC is better on I2S as there is no Subbu I2S DAC (yet)

- Currymans DAC has the JG buffer which seems a nice addition

- ...............DAC sounds better even if comparing is hard to do ;)

We are no competitors folks. As you can see Daniel has a Subbu V3 and I have a Curryman DAC too.
 
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albertli

albertli

Member
Joined 2004
Albert,
Bigger isn't always better. I'd take the 10uf SAL-RPM and use it for C21. Then I'd find a 4.7uf cap for C32. Either a SAL-RPM or a Wima MKS cap. If you don't have either of those then an electrolytic cap.

I don't think you need the LM2940 preregulator. The circuit will work fine without it. The long wires to the LM2940 and the extra caps could cause unwanted problems.

Having all the voltages correct doesn't mean the capacitors are wired correctly. It's worth checking their orientation just in case.

Gary,
I finished re-group all the above and the V3 is singing beautifully now. The highs and mids obviously improve by a big margin. I really don't know that pre-regulator did so much degradation to the sound. I have the C21 with 10uf, C22 with 470/6.3 Sepc, but the C35 with 10uf still for I don't have nothing smaller. The MKS 4.7uf is on the way to me. Will have it replaced later. Can I parallel a MKS 4.7uf at the input ??
I have all the parts for the JG buffer. I'd use J310 n K170, would start putting them together after checking the Idss for the K170. Heeee..I just finished surfing the internet for the ' how to '. So I'll do it asap. PSU is Salas V1. Will post after.
Thanks so much for the advice
Albert
 
G

GaryB

Member
Joined 2002
Paid Member
albertli said:
Gary,
I finished re-group all the above and the V3 is singing beautifully now. The highs and mids obviously improve by a big margin.
Click to expand...
Very glad to hear that things are sounding better now. How much has the gap between the V3 and your Audionote DAC narrowed?

albertli said:
I have the C21 with 10uf, C22 with 470/6.3 Sepc, but the C35 with 10uf still for I don't have nothing smaller. The MKS 4.7uf is on the way to me. Will have it replaced later. Can I parallel a MKS 4.7uf at the input ??
Click to expand...
I am not positive but are you asking if you can use the 4.7uf MKS cap for the SPDIF input instead of the 3.3uf MKS that I recommended as a good mod? If that is the question then the answer is yes - you can try that. I haven't tried that exact value but it should work well and not do any harm.

albertli said:
I have all the parts for the JG buffer. I'd use J310 n K170, would start putting them together after checking the Idss for the K170. Heeee..I just finished surfing the internet for the ' how to '. So I'll do it asap. PSU is Salas V1. Will post after.
Thanks so much for the advice
Albert
Click to expand...
You're welcome. I look forward to hearing your impressions once you add the JG buffer/filter.

---Gary
 
albertli

albertli

Member
Joined 2004
GaryB said:
Very glad to hear that things are sounding better now. How much has the gap between the V3 and your Audionote DAC narrowed?
The V3 has better bass definition but loses on mids n highs. Audionote gives a better mids in body/ lushness, delicated highs.


I am not positive but are you asking if you can use the 4.7uf MKS cap for the SPDIF input instead of the 3.3uf MKS that I recommended as a good mod? If that is the question then the answer is yes - you can try that. I haven't tried that exact value but it should work well and not do any harm.
OK. I go with the mks4.7


You're welcome. I look forward to hearing your impressions once you add the JG buffer/filter.

Albert
Click to expand...
 
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albertli

albertli

Member
Joined 2004
GaryB said:
Very glad to hear that things are sounding better now. How much has the gap between the V3 and your Audionote DAC narrowed?
The V3 has better bass definition but loses on mids n highs. Audiometer gives a better mids in body/ lushness, delicated highs.


I am not positive but are you asking if you can use the 4.7uf MKS cap for the SPDIF input instead of the 3.3uf MKS that I recommended as a good mod? If that is the question then the answer is yes - you can try that. I haven't tried that exact value but it should work well and not do any harm.
OK. I go with the mks4.7


You're welcome. I look forward to hearing your impressions once you add the JG buffer/filter.

---Gary
Click to expand...
 
G

GaryB

Member
Joined 2002
Paid Member
freeman said:
Gary, where/how do you implement bypass for c22? Thanks. Regards.
Click to expand...
There is already a bypass cap for C22 on the V3 board - C36. The BOM recommends a 1uf 25v X7R cap in the 0805 size. The datasheets for the polymer caps suggest that increasing this to 10uf would be a good thing. I did this on my V3 DAC and think it's a good thing but I didn't make the change in a controlled manner, so there is always the chance that I'm hearing what I think is an improvement. An example of the part you could buy is Murata EMK212BB7106MG-T, a 10uf 16v X7R cap in the same 0805 size. It costs $0.68 at Mouser. There isn't anything special about this cap - there are quite a few alternatives if you can't find exactly this part. I also replaced all the 1uf caps that are used to bypass big electrolytics - C5, C7, C19, C20. These are 1210 size, so a different part is called for here. For example, TDK C3225X7R1E106K250AC is a 10uf 25v X7R cap in 1210 package. It costs $0.72 at Mouser.
The layout of the V3 is flexible enough that you could use the 1210 parts for C36 or the 0805 parts for C5, C7, C19, and C20 if you're careful.

As always, experiment with this at your own risk. The changes associated with tweaking these bypass caps is at best subtle, so I wouldn't make this a high priority. But I would be interested in your experience if you have time to do some experiments.
---Gary
 
E

Eldam

Banned
Joined 2012
Hi

Is anybody get two subbu DAC with different setting ?

I have been testing different set up from 2 days. It's very sensitive to external environment : source + spidf wire. Just test it with two different Squeeze Box Duet and one CD player with many Spidf wires.

I can understand a little the choice of orange "rain drop" cap because I test it without these caps but panasonic polymer (marked blue for the minus) near the regs : it's to much dry, lake of body or "flesh"... I surmise the fault of these to bad polymer caps or the SEPC at C22. WIll test soon with a // Black Gate BG N 33 uF on the C22. I have a big sucess with this // on my SPIDF PS on one of my SB Duet.

Maybe SEPC are missing of flesh too : maybe the expensive Panasonic FC (marked red on the minus) should be a good choice like the orange rain drop...

My setup is with a 470 uF SEPC for C22 and a 0,22 uF multilayer MKC as DC stoper for SPIDF.
 
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jean-paul

jean-paul

Disabled Account
Joined 2002
Does the source have an SPDIF transformer ? If not adding one might be the solution. Noticed this too (somewhat) with sources that were directly coupled. Most sources have transformers except for all the "new" sources that I try out now... I am waiting for some SPDIF transformers to try out and see if it helps.

Do you use good industrial 75 Ohm coax cable and 75 Ohm BNC connectors both at source and DAC ? Also be aware that the DAC and caps need to settle little more than 2 days to sound/perform optimal.

Panasonic SEPC 470 µF for C22 is in all my current 3 examples of Subbu V3 in which i use them an improvement but ... in theory the ceramic caps that are in parallel should be changed from 1 µF to 10 µF. I built one like that but it is waiting for a few parts. The fifth example has SAL RPM caps only and sounds very good as well (68 µF SAL RPM 122 for C22).

A picture would help. There can be many factors that have an influence on the total outcome including you ;)
 
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E

Eldam

Banned
Joined 2012
hi Jean-Paul,

I believe than the SB Duett have no dc caps nore smd transformer at between chip and SPIDF conector.

I still use Chinch to switch between differents sources and DACS and try diferent on shelves wire like DIY ones. I always use on shelves wires for that from different sources like eg aeronautics tripled shelded... or hifi brands :eek:

Thanks I will stay with C22 SEPC but change the Nichicon "blue" F 2n5 for the "red" FP 29a before the smd regs.

I just put 4,7 (but same model as the BOM) Uf near the Wolfson 8804 because have already it.

Moste of time I don't like after the PS caps like the FC at first place for the PS IC. I will test a slower long life caps, Lelon gave me goods results in some preamp here in Pi filter. I will stay the second FC caps after the SMD coil. removed already the 0,1 uf Caps...

Step by step to understand and not remove better genuine conf. It's always a setting up for its own HIFI environment !
 
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