[IPodPJ]

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A rocket science really...

Seems easy enough.

 
So apparently the new boards use jumpers instead of the DIP?  I wonder why he did this.  It could be a SQ thing, since many people believe DIPs provide inferior SQ.

 

[IPodPJ]

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Agreed, it's giving me some considerable pause for thought since the MAX mods did address the few shortcomings that the RE1 (and the Phoenix) had. A further tipping of the sound signature attributes towards "Hi Fi" (  & in conjunction with the positive changes brought on by the MAX mods which mirror the V5 descriptions in some respects) might too much of a good thing. Hmmm...only one way to find out I suppose.
 
Peete.

 
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With the review posted on the v5,  I'm having second thoughts on upgrading.  One of the things I like best about this RE1 is the natural organic sound,  from that review I read it as rev5 is more HIFI.

 
Well mine shipped out today, so I'll let you guys know what I hear between them.  I must have version 2 or 3 of the DSP-1 module, whatever it was when the RE7 came out, and I love it's organic and natural sound.  With the two boards on hand, it should be easy to compare but I surely won't be swapping them in and out over and over.  I've had the RE7 for quite some time now and have a really good handle on it's sound signature -- which also, in my system will vary depending on what power cord is being used with it and on the Transporter, and whether or not either of those is plugged into the wall or into the regenerator.
 
I can't imagine Kingwa would release a new version that wouldn't sound as good as previous ones, so you should probably wait until more impressions come from other users before coming to conclusions.

 

[regal]

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I can't imagine Kingwa would release a new version that wouldn't sound as good as previous ones, so you should probably wait until more impressions come from other users before coming to conclusions.

Not a matter of not as good,  everyone has different taste buds.
 
 
 
Anyway I did some testing of the my new to me RE1 in comparison with my previous DAC19mk3.   As you may know the PCM1704 is very sensitive to any load on its i-out (current output.)   Testing by Swenson and others have always shown lowest distortion at less than 10 ohms,  ideally per Ti it should feed a zero ohm virtual ground.   This is very hard to achieve without resorting to opamps.
 
With the DAC19,  the i-out was sitting at 35 mV's playing a 0dBs 1khz sine wave,  which corresponds to 14 ohms,  not bad but room for improvement.
 
With the RE1 I measured 1 mV which is the resolution of my fluke,  so the I/V is less than a 0.42 ohm load.   This is phenomenal considering Kingwa's design has no opamps or NFB for the I/V.  
 

 

[vrln]

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With the review posted on the v5,  I'm having second thoughts on upgrading.  One of the things I like best about this RE1 is the natural organic sound,  from that review I read it as rev5 is more HIFI.

Kingwa just mailed me to say the new DSP-1 I have only had 10 mins burn in while the previous one was burned in fully, so it should change a lot. So those early findings will probably change a lot... I´ve updated the original post. But yes, currently the non-burned in DSP-1 is clearly more HIFI. Personally I think it will change as it burns in, I remember someone on head-fi saying once that Kingwa doesn´t like sending new DSP-1´s out because they sound so different without burn-in. We´ll see. If it doesn´t change, I´m definately keeping both. 
 
If you have an older version than 4, I´d still recommend upgrading to version 4 at least. It sounds exactly natural and organic.

 

[FauDrei]

With the RE1 I measured 1 mV which is the resolution of my fluke,  so the I/V is less than a 0.42 ohm load.   This is phenomenal considering Kingwa's design has no opamps or NFB for the I/V. 

Er... I'm not sure I am talking about the same thing, but under each of four RE-1 ACSS modules you have OPA2134 acting as DC servo...
 
BTW, do we gain anything if we swap those OPA2134 with, let's say OPA2228?

 

[Currawong]

According to Kingwa, you don't need to swap them out. 

 

[regal]

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Er... I'm not sure I am talking about the same thing, but under each of four RE-1 ACSS modules you have OPA2134 acting as DC servo...
 
BTW, do we gain anything if we swap those OPA2134 with, let's say OPA2228?

Those have nothing to do with I to V conversion.  Those are simply opamp servos operating at DC and have nothing to do with the impedance (load) of the i-out from the PCM1704.  I can explain further if you don't understand what I mean.

 

[ccschua]

Instead of using Capacitors to prevent any DC drift, DC servo is used. its component choice is not critical as Regal mention.

 

[vrln]

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Those have nothing to do with I to V conversion.  Those are simply opamp servos operating at DC and have nothing to do with the impedance (load) of the i-out from the PCM1704.  I can explain further if you don't understand what I mean.

Quite off topic (I don´t mean just this post, countless similar ones), but I have to say your posts always delight me. Thanks for all the technical insight you´ve shared here.

 

[ccschua]

I have been running the audio-gd ref1 with the audio-gd transport, pre and power amps. So far I like the synergy very much.
 
It is a well connected gears working to bring out the best in audio-gd design efforts and I pretty enjoy the sound signature. Alas the short coming is my speaker and a host of other accessaries such as Rack, anti vibration, etc. now. 
 
I am completely floated by the musical symbols.

 

[Vandal]

Great DAC, whew, these things are so complicated and finely made. Have fun. Though, as a hobbyist photographer, mediocre shooting

 

[Pricklely Peete]

Well I have all of the parts ordered for the CD7 MAX mod...hopefully I'll be able to update the thread by next Friday with a completed and working CD7 MAX (

). All of the NoVer caps will be replaced (large value with Mundorf M'Lytic) and smaller values with Nichicon FG, some Vishay Roderstein MKP-1837's once again (bypass duty) as well as the clock crystal (from 3 ppm to the current part used in the CD7FV...a .05ppm TXCO). I have no idea if this mod will be worth the effort but if it's even half the improvement the RE1 MAX mod brought to the table then I will be very happy indeed. I'm itching to get this "system MAX mod" project completed...it has taken the better part of 6 months thus far...fun stuff to say the least

This mod is quite a bit smaller ( and cheaper) than the Phoenix or the RE1 units were.
 
The V5 DSP will have to wait (for now).
 
Peete.

 

[FauDrei]

Peete, is this clock swap a "plug&play" thing?
 
If it is, I'm interested to do the same to both clocks in Digital interface and on RE-7 digital board. Any recommended part number?
 
BTW, a couple more RE-1 tweaking ideas for RE-1's digital board:
 

1. change all 75Ω Dale resistors on DSP-1 and RE-1's digital board with Caddock MK-132 equivalents (9 pieces)
2. change 74HC04 inverter to 74VHC04
3. change 4n7 and 68n (yellow) film capacitors near DIR9001 to 1% tolerance polypropylene capacitors of the same sizes
4. bypass all 1uF (red) Wima's with 1% polypropylene caps (3 pieces)

 

[Currawong]

I realised when I received my V5 board that I wouldn't be able to directly compare it to the V1, except from memory.  However, I could compare my Cambridge 840c again to the upgraded Ref 1, which I did beforehand.  With the V1, there wasn't really a lot of difference between the Ref 1 and the 840c, which was a bit disappointing.  I was still feeling that instruments could sound better than they did, but haven't had any other high-end DAC handy to compare with.  However, with the V5 the increase in naturalness and detail in the Ref 1 is plainly obvious now.

 

[Pricklely Peete]

 
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Peete, is this clock swap a "plug&play" thing?
 
If it is, I'm interested to do the same to both clocks in Digital interface and on RE-7 digital board. Any recommended part number?
 
BTW, a couple more RE-1 tweaking ideas for RE-1's digital board:
 

1. change all 75Ω Dale resistors on DSP-1 and RE-1's digital board with Caddock MK-132 equivalents (9 pieces)
2. change 74HC04 inverter to 74VHC04
3. change 4n7 and 68n (yellow) film capacitors near DIR9001 to 1% tolerance polypropylene capacitors of the same sizes
4. bypass all 1uF (red) Wima's with 1% polypropylene caps (3 pieces)

AFAIK...the clock part needs to be unsoldered (CD7) ...this is a guess since the actual circuit itself is covered with a copper shield (box) with some dampening material glued to the top of that cover. I just got an email from Edwin this past morning saying the clock part is out of stock and he didn't say whether they would be getting anymore. I asked ..hopefully they will have some more on order in the near future otherwise I'll have to spend that money (which isn't much) on something else.
 
The mods you have selected ...not sure what the change of Hex inverter (74HC04 is a hex converter IIRC)  will bring but I'll let you be the judge of that one everything else looks good to me. Try and match the Caddocks as closely as possible (since you are going to this level ).
 
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I realised when I received my V5 board that I wouldn't be able to directly compare it to the V1, except from memory.  However, I could compare my Cambridge 840c again to the upgraded Ref 1, which I did beforehand.  With the V1, there wasn't really a lot of difference between the Ref 1 and the 840c, which was a bit disappointing.  I was still feeling that instruments could sound better than they did, but haven't had any other high-end DAC handy to compare with.  However, with the V5 the increase in naturalness and detail in the Ref 1 is plainly obvious now.

That is interesting news Curra, do you have to change a few things physically to install the V5 (rather than just popping it in)...would you say the V5 DSP equipped RE1 is now on par with the 840C or is it surpassing it ?
 
 
Peete.