Upgraded Single Board PCM1794 NOS DDDAC

emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x 3, + 3set JFEct + 3set SuSumu(request for pre solder if available)
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x1 + 1 set JFETS + 1 set Susumu
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x2 + 2 set JFETS + 2 set Susumu
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. x1 + 1 set JFETS + 1 set Susumu
ed linssen x1 + 1set JFETS + 1 set Susumu
tuyen x1 + 1 set JFETS + 1 set susumu
mr_whocares x2 + 2 set jfets + 2 set susumu
dwjames x1 + 1 set jfets + 1 set susumu
Sovereign x2 + 2 sets JFETS + 2 sets Susumu
titus2002 x1 + 1 set JFETs + 1 set Susumu
rickmcinnis x1 + 1 set JFETS + 1 set Sumumu
pdb x1 + 1 set JFETS + 1 set Susumu
odem81 x1 + 1 set JFETS + 1 set Susumu
tods x2 + 2 set jfets + 2 set susumu
thommy x2 + 2 set JFETS + 1 set Susumu
NicB x1 + 1 set JFETS + 1 set Susumu

PCB= 36
Parts= 32
 
Default CCS GB - (re)Corrected List

emyeuoi (CCS x 2)
carlsor (CCS x 20)
juancho (CCS x 4)+parts
crazyfrog (CCS x2)
mk57 (CCS x 8) + parts
SimonJ (CCS x 2) + parts
PET-240 CCS x 12 + 4 x parts
sterlingmck (CCS x 4) + parts
zz1969 (CCS x 8) + parts
kurand (CCS x 8) + parts
mbcoffman (CCS x 2) + parts
Myint67 (CSSx16) + Parts
tuyen (CCS x 8) + parts
Brumjam (CCS x 4) + parts
mr_whocares (CCS x 2) + parts
tods (CCS x 8) + parts
IanS1 (CCS x 4) + Parts
dwjames (CCS x 2) + parts
titus2002 (CCS x 8) + parts
BDL (CCS x 2) + parts
Sovereign1 (CCSx4) +Parts
rickmcinnis (CCS x 2) + parts
Superberg (CCS x 20) + parts
Naimster(CCS x 16) + parts
pdb (CCS x 4) + parts
ed linssen (CCS x 4) + parts
pz1: (CCS x 8) + parts
odem81 (CCS x 2) + parts
vedior (CCS x 2) + parts
thommy: (CCS x 6) + parts
NicB: (CCS x 2) + parts
chevron: (CCS x 2) + parts

Total CCS = 198
Parts = 166
 
emyeuoi (CLOCK x 1)
Superberg (CLOCK x 1)
BDL (CLOCK x 1) + VHCs soldered
Juancho (clock x 1) + VHCs soldered
chevron (CLOCK x 1) + VHCs soldered
pz1 (clock x 1) + VHCs soldered
sterlingmck (clock x 2) + VHCs soldered
vedior (clock x 1) + VHCs soldered
Crazyfrog (clock x 1) + VHCs soldered
ed linssen (CLOCK x 1)
NicB (clock x 1) + VHCs soldered
Dwjames (clock x 1)
SimonJ (clock x 1)
Sovereign1 (clock x1) + VHS soldered
carlsor (clock x 1)

Total: 17+ 10VHCs
 
Sorry yes, my bad... the DC offsets for pos and neg are both +2.7v or thereabouts, So the DC offset between pos and neg is minimal. Usually only a couple of mv, depending on how accurately matched the I/V resistors are I believe.
The audio signals on pos and neg are the same, but opposite phased.

So what some people have been doing is ignoring the common (dac gnd), and just using pos and neg as a single ended output with almost no DC offset and not using any caps or transformers on this output. Neg becomes RCA gnd. Obviously it's not the recommended route (and I wouldn't be happy doing it on an amp without some form of coupling capacitors or transformers before the power stage) but some have found this works well for them.

Hi,

What happens is that both connections are referenced to each other and floating from ground. The DC that is left is the difference between the both DC levels.

I use the pos-neg outputs directly coupled to my amps. The amps have an input volume transformer and the input wires are floating from ground.
This is basically the same ase using an output transformer.

Regards,
 
Sorry I would like to short 1buffer ,
emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x 2+2 Set JFETS+2 set susumu
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x1 + 1 set JFETS + 1 set Susumu
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x2 + 2 set JFETS + 2 set Susumu
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. x1 + 1 set JFETS + 1 set Susumu
ed linssen x1 + 1set JFETS + 1 set Susumu
tuyen x1 + 1 set JFETS + 1 set susumu
mr_whocares x2 + 2 set jfets + 2 set susumu
dwjames x1 + 1 set jfets + 1 set susumu
Sovereign x2 + 2 sets JFETS + 2 sets Susumu
titus2002 x1 + 1 set JFETs + 1 set Susumu
rickmcinnis x1 + 1 set JFETS + 1 set Sumumu
pdb x1 + 1 set JFETS + 1 set Susumu
odem81 x1 + 1 set JFETS + 1 set Susumu
tods x2 + 2 set jfets + 2 set susumu
thommy x2 + 2 set JFETS + 1 set Susumu
NicB x1 + 1 set JFETS + 1 set Susumu

PCB= 35
Parts= 31
 
Sorry I would like to short 1buffer ,
emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x 2+2 Set JFETS+2 set susumu
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x1 + 1 set JFETS + 1 set Susumu
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x2 + 2 set JFETS + 2 set Susumu
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. x1 + 1 set JFETS + 1 set Susumu
ed linssen x1 + 1set JFETS + 1 set Susumu
tuyen x1 + 1 set JFETS + 1 set susumu
mr_whocares x2 + 2 set jfets + 2 set susumu
dwjames x1 + 1 set jfets + 1 set susumu
Sovereign x2 + 2 sets JFETS + 2 sets Susumu
titus2002 x1 + 1 set JFETs + 1 set Susumu
rickmcinnis x1 + 1 set JFETS + 1 set Sumumu
pdb x1 + 1 set JFETS + 1 set Susumu
odem81 x1 + 1 set JFETS + 1 set Susumu
tods x2 + 2 set jfets + 2 set susumu
thommy x2 + 2 set JFETS + 1 set Susumu
NicB x1 + 1 set JFETS + 1 set Susumu

PCB= 35
Parts= 31

Hi Myint,

No problem, you still need to solder the parts?

Regards,
Enrico
 
Buffer bare PCB - CLOSED

Dear All,

The GB for the Buffer PCB is CLOSED.

Below the Final List:

emyeuoi (x1)
PET-240 x2 + 2 set JFETS + 2 set Susumu
Myint67x 2+2 Set JFETS+2 set susumu
Juancho x2 + 2 sets JFETS + 2 sets Susumu
Sterlingmck x2 + 2 set JFETS + 2 set Susumu
BDL x1 + 1 set JFETS + 1 set Susumu
mbcoffman x1 + 1 set JFETS + 1 set Susumu
carlsor x1
naimster x2
kurand x1 + 1 set JFETS + 1 set Susumu
brettlb x2 + 2 set JFETS + 2 set Susumu
SimonJ x1 + 1 set JFETS + 1 set Susumu
JanGr. x1 + 1 set JFETS + 1 set Susumu
ed linssen x1 + 1set JFETS + 1 set Susumu
tuyen x1 + 1 set JFETS + 1 set susumu
mr_whocares x2 + 2 set jfets + 2 set susumu
dwjames x1 + 1 set jfets + 1 set susumu
Sovereign x2 + 2 sets JFETS + 2 sets Susumu
titus2002 x1 + 1 set JFETs + 1 set Susumu
rickmcinnis x1 + 1 set JFETS + 1 set Sumumu
pdb x1 + 1 set JFETS + 1 set Susumu
odem81 x1 + 1 set JFETS + 1 set Susumu
tods x2 + 2 set jfets + 2 set susumu
thommy x2 + 2 set JFETS + 1 set Susumu
NicB x1 + 1 set JFETS + 1 set Susumu

PCB= 35
Parts= 31


Thanks to all of you for your kind support in this my first experience with a GB.

Best Regards,
Enrico
 
CCS Circuit PCB - GB CLOSED

Dear All,

The GB for the CCS PCB is CLOSED.

Below the Final List:

emyeuoi (CCS x 2)
carlsor (CCS x 20)
juancho (CCS x 4)+parts
crazyfrog (CCS x2)
mk57 (CCS x 8) + parts
SimonJ (CCS x 2) + parts
PET-240 CCS x 12 + 4 x parts
sterlingmck (CCS x 4) + parts
zz1969 (CCS x 8) + parts
kurand (CCS x 8) + parts
mbcoffman (CCS x 2) + parts
Myint67 (CSSx16) + Parts
tuyen (CCS x 8) + parts
Brumjam (CCS x 4) + parts
mr_whocares (CCS x 2) + parts
tods (CCS x 8) + parts
IanS1 (CCS x 4) + Parts
dwjames (CCS x 2) + parts
titus2002 (CCS x 8) + parts
BDL (CCS x 2) + parts
Sovereign1 (CCSx4) +Parts
rickmcinnis (CCS x 2) + parts
Superberg (CCS x 20) + parts
Naimster(CCS x 16) + parts
pdb (CCS x 4) + parts
ed linssen (CCS x 4) + parts
pz1: (CCS x 8) + parts
odem81 (CCS x 2) + parts
vedior (CCS x 2) + parts
thommy: (CCS x 6) + parts
NicB: (CCS x 2) + parts
chevron: (CCS x 2) + parts

Total CCS = 198
Parts = 166


Thanks and Best Regards,
Enrico
 
1/2 Clock Delay PCB and parts - GB CLOSED

Dear All,

The GB for the 1/2 Clock Delay PCB is CLOSED.

Below the Final List:

emyeuoi (CLOCK x 1)
Superberg (CLOCK x 1)
BDL (CLOCK x 1) + VHCs soldered
Juancho (clock x 1) + VHCs soldered
chevron (CLOCK x 1) + VHCs soldered
pz1 (clock x 1) + VHCs soldered
sterlingmck (clock x 2) + VHCs soldered
vedior (clock x 1) + VHCs soldered
Crazyfrog (clock x 1) + VHCs soldered
ed linssen (CLOCK x 1)
NicB (clock x 1) + VHCs soldered
Dwjames (clock x 1)
SimonJ (clock x 1)
Sovereign1 (clock x1) + VHS soldered
carlsor (clock x 1)

Total: 17+ 10VHCs

Thanks and Best Regards,
Enrico
 
This my first GB was an incredible adventure... well, still it is because now I have a lot to do 🙂

Tomorrow I hope to have the final quotation from the manufacturer and to be able to give you the final prices.

Thanks again to all of you guys.

Best Regards,
Enrico
 
GB SMD Parts

These Group Buys are about four times as successful as I first expected. This is good for persons upgrading their DACs, but a lot of work for me in the next few weeks. Good thing I'm retired.

I expect to receive 300 2SK208 JFETs in the mail today. These tend to measure very consistent so my first priority will be to mail sets of 2SK208 JFETs and fixed SMD resistors to those who ordered only CCS boards from Enrico. Again, the price is $5.50 per set (enough for 2 CCS boards) plus $4 shipping in a first class letter.

Anyone who ordered the Buffer board and CCS boards can receive their CCS SMD parts earlier if they pay the additional $4 postage. The Buffer and CCS upgrades are totally independent.

The BF862 buffer JFETs measure all over the place from one chip to the next. This means I have to measure all 400 BF862s before I group them into matched sets.

On the positive side, I get to listen to my fully upgraded single board DDDAC while doing all this.
 
Susumu RG Rload Resistors

Rload Susumu RG Resistors: I have been asked in a PM if I can also provide Susumu RG SMD Rload resistors along with other SMD parts.

IMO it is important to upgrade the RLoad resistors above the stock Dale RN's. The TX2575 z-foils and Rhopoints are reported to be the best, but are expensive and 133ohms are special order. The Tantalums are a more reasonable priced upgrade but the closest I was able to get was 2X270ohms. The Susumu RG SMD transistors have greater clarity than the Dale RN's and sound at least as good as the Tantalums to me. Some adaptation is needed to mount SMD resistors where holes are provided like the DAC main boards.

What I can do is provide ten 0.1% 270ohm SMD Susumu 1206 RG resistors plus a 2cm X 4cm piece of adhesive backed tinned copper sheeting for SMD installation for $8 plus shipping in an envelope. No extra shipping if mailed with other parts order. Paralleling 270 ohm resistors provides 135 ohms for a single board DAC. The large Susumu RG is not available in 133 ohms, but this difference should not be audible. The purist can add a 3rd 10K resistor in parallel to get 133.2 ohms. Four 10K SMD resistors add $3 to the price. For 2 Board DACs needing 66-67 ohms - three 200 ohm SMDs in parallel equal 66.7 ohms. Cost for 14 0.1% 200 ohm Susumu's and copper sheeting piece is $11 plus shipping. The wattage load for a 4+ board DAC is too much for SMD resistors. PM or email me if interested.

I will be posting pictures of how I use the tinned copper sheeting to install the SMD resistors in the Rload positions as soon as I receive my next Main Board.
 
Final Prices

Hi All,

below are the final prices for the various bare PCB:

1 - BUFFER bare PCB - 13.00 USD

2 - CCS bare PCB - 2.00 USD

3 - 1/2 Clock Delay bare PCB - 18.00 USD

Unfortunately the cost of the 1/2 Clock PCB is much higher than the others. This because the manufacturer apply a fix initial price to setup the machines for each different board. More boards are realized with the same setup, less is the price of each board.

Now the options:

1a - Solder SMD parts and continuity check for the BUFFER Circuit - 12.00 USD

3a - Supply and solder of the SMD part and continuity check for the 1/2 Clock Delay Circuit - 5.00 USD

Finally the handling and shipping. I will send from Korea through Korea Post.
The Korea Post prices are expensive and very complicate to calculate. They divide the various country in 4 "regions" and inside each region they have also the exception. In addition the price vary with the weight... really complicate 😕

I am sorry but I will apply a unique price of 12.00 USD for all the countries that will include the handling and a part of the paypal fees.
As per my experience sending through normal post, not traced and not insured will take maximum 3 weeks to reach USA and as of today I don't loose any shipment.

If anyone need a fast and traced shipment please highlight it in the reply PM.

I will start to send you the PM for the payment... please reply to my PM with your exact address including the postal code.

Thanks and Regards,
Enrico
 
@ pdb,

look like I can't send a PM. You are not allowed or you choose to do not receive PM.

I don't know how can reach you... can you please check?

Regards,
Enrico
Sorry..... I noticed some problems the other day, but carlsors went through?!? I'll investigate - until then just send to pdb(at)mit(dot)bolignet(dot)dk Thank you so much for all your effort and kind patience 🙂 All the best, Per
 
Rload Susumu RG Resistors:
IMO it is important to upgrade the RLoad resistors above the stock Dale RN's. The TX2575 z-foils and Rhopoints are reported to be the best, but are expensive and 133ohms are special order. The Tantalums are a more reasonable priced upgrade but the closest I was able to get was 2X270ohms. The Susumu RG SMD transistors have greater clarity than the Dale RN's and sound at least as good as the Tantalums to me. Some adaptation is needed to mount SMD resistors where holes are provided like the DAC main boards.
.

I tried old Holco 130R and it's better than Dale.