Hi Spartacus and Nicmac,
I can confirm the dropout voltages as 1v5 for the mini shunts and around 3v for the mini series regs. They will both work happily from a 5 volt rail.
One thing to be careful of, for those using a Z1A-05 shunt reg for the 5 volt rail, the current setting will have to be increased to cope with the additional mini reg load. I set the shunt current output capability of the Z1703v3 at 50ma for Leo for use with the Buffalo 32S. This gives a total draw of around 80ma per reg including the reg bias currents. The Z1A-05 current should be set for 250ma minimum when using 2 of the Z1703v3 shunts and 1 of the S1701v2 series regs. Replacing the LME49710 op-amp buffers with a pair of Z1703v3 regs will require the Z1A-05 current to be set to around 410ma (a 2R7 1w current setting resistor on the Z1a will give around 460ma for a little margin). The dropout voltage of the Z1A is around 5 volts. Make sure the input voltage to the Z1A when run at close to 0.5amps is not more than 12 volts. Remember shunt regs are not very thermally efficient and they will run hot. I like to advise each application individually to ensure regs are going to be run comfortably within thermal ratings.
NicMac, the Z173v3 regs I supplied to you were set for 120ma out 150ma total so just be sure the supplies feeding them have enough current/dissipation capacity when adding more shunt regs.
The shunt regs draw a constant current from the supply so they can be used as you have described, Spartacus, with a dropping resistor to reduce the reg input voltage.
If anyone needs application help you know where I am.
Regards
Paul
I can confirm the dropout voltages as 1v5 for the mini shunts and around 3v for the mini series regs. They will both work happily from a 5 volt rail.
One thing to be careful of, for those using a Z1A-05 shunt reg for the 5 volt rail, the current setting will have to be increased to cope with the additional mini reg load. I set the shunt current output capability of the Z1703v3 at 50ma for Leo for use with the Buffalo 32S. This gives a total draw of around 80ma per reg including the reg bias currents. The Z1A-05 current should be set for 250ma minimum when using 2 of the Z1703v3 shunts and 1 of the S1701v2 series regs. Replacing the LME49710 op-amp buffers with a pair of Z1703v3 regs will require the Z1A-05 current to be set to around 410ma (a 2R7 1w current setting resistor on the Z1a will give around 460ma for a little margin). The dropout voltage of the Z1A is around 5 volts. Make sure the input voltage to the Z1A when run at close to 0.5amps is not more than 12 volts. Remember shunt regs are not very thermally efficient and they will run hot. I like to advise each application individually to ensure regs are going to be run comfortably within thermal ratings.
NicMac, the Z173v3 regs I supplied to you were set for 120ma out 150ma total so just be sure the supplies feeding them have enough current/dissipation capacity when adding more shunt regs.
The shunt regs draw a constant current from the supply so they can be used as you have described, Spartacus, with a dropping resistor to reduce the reg input voltage.
If anyone needs application help you know where I am.
Regards
Paul
OK. I think I'm done now
Out with the buffer op-amps and in with a couple of 3v3 shunts for Avcc.
It looks like Frankenstein but sounds divine..... I think the Avcc "upgrade" makes an evident improvement, but I will have to listen more before I can pinpoint more precisely where the sonic improvement are. I may try some different supplies for VA and for the VD JSR that now has to cope with about 0.7A current draw for the 5 mini regs.
Other than that its time to box it all and enjoy!
I'm just waiting for AC1/Femto from Russ and Brian to close this up for a few years and focus on my power amp...........
Out with the buffer op-amps and in with a couple of 3v3 shunts for Avcc.
It looks like Frankenstein but sounds divine..... I think the Avcc "upgrade" makes an evident improvement, but I will have to listen more before I can pinpoint more precisely where the sonic improvement are. I may try some different supplies for VA and for the VD JSR that now has to cope with about 0.7A current draw for the 5 mini regs.
Other than that its time to box it all and enjoy!
I'm just waiting for AC1/Femto from Russ and Brian to close this up for a few years and focus on my power amp...........
Attachments
Thanks for sharing. 
I think I should replace the digital in screw terminal with connectors like you did.
How big of an improvement is the AVCC mod (compared to the VD/XO mod)? What's the main reason that you picked this approach over the one that's described in the manual?
Thank you in advance!
I think I should replace the digital in screw terminal with connectors like you did. How big of an improvement is the AVCC mod (compared to the VD/XO mod)? What's the main reason that you picked this approach over the one that's described in the manual?
Thank you in advance!
Hi Nic
I see you've soldered the regs diectly across the decoupling cap's pads, like Leo did. Is this cap the original 10u ceramic?
I did it like this, so I could try other decoupling caps, and so the regs were soldered to through hole pillars for robustness. (Ignore the fluff!). Disadvantage is the increased distance of the reg to the AVCC pin
Paul
I see you've soldered the regs diectly across the decoupling cap's pads, like Leo did. Is this cap the original 10u ceramic?
I did it like this, so I could try other decoupling caps, and so the regs were soldered to through hole pillars for robustness. (Ignore the fluff!). Disadvantage is the increased distance of the reg to the AVCC pin
Paul
Attachments
I think the improvement with the Avcc tweak is bigger than with the VD/XO mods. The biggest change was however better VA power (the first thing I did).
The Avcc mod described in the manual does not change the power source for Avcc only its absolute voltage - as far as I have understood.
It was a walk in the park mounting the regs on the decoupling caps and as I'm not very likely to proceed with cap rolling experiments I simply left what was there in.
Nic
Bloody good regs aren't they Nic
upgrading the AVCC regs on the Buffalo24 proved to be a very worthwhile upgrade so doing the same on this dac would prrobably give same results
Yes they are quite extraordinary - and even if a new improved DAC will come out the regs will be recycledBloody good regs aren't they Nic
P.S. Do you retain power for the µC when replacing the VD/XO regs? I lost power for Volumite but now supply this separately.
I have a feeling that a great deal of the magic of the Buffalo may lie in the way the ESS registers have been set by TPA and I'm a little bit worried that I may be messing with that too.... (maybe a comment from Russ or Brian would be informative here).
So basically, all I have to do is remove IC2/IC3 (or is it okay to just lift the output pins) and mount the regs on C1/C2?
Thank you in advance!
I guess lifting the output pin is sufficient but in that way I guess the op-amps would continue to dissipate heat. I also removed two electrolytics to get space for the new regs.
Hi Chipzahoy,
All good things come to those who wait. Patience is a virtue.
Seriously, the supply of regulator modules is a sideline at present. There are not enough regular orders to warrant me holding thousands of pounds worth of stock. The reg modules have to pay their way and I am not interested in having *anker funding for this. Therefore, for the moment, built to order with cash up front is how it is.
Aside from some office help, there is only myself to build your orders. I have refurbished my workshop earlier this year to allow speedier assembly and test Aside from a couple of special orders where parts I have ordered for these are out of stock, and some custom work, I am now back on my normal build schedule lead time which is around 22 WORKING days. I will be doing my best to keep to this schedule from now on.
Regards
Paul
All good things come to those who wait. Patience is a virtue.
Seriously, the supply of regulator modules is a sideline at present. There are not enough regular orders to warrant me holding thousands of pounds worth of stock. The reg modules have to pay their way and I am not interested in having *anker funding for this. Therefore, for the moment, built to order with cash up front is how it is.
Aside from some office help, there is only myself to build your orders. I have refurbished my workshop earlier this year to allow speedier assembly and test Aside from a couple of special orders where parts I have ordered for these are out of stock, and some custom work, I am now back on my normal build schedule lead time which is around 22 WORKING days. I will be doing my best to keep to this schedule from now on.
Regards
Paul
Hi all,
I have a Buf32s powered by LCDPS + 2*LCBPS using 3* 15 VA trafos supplied by TPA. I love the sound coming out, but being a diyer, temptation is hard to resist when I hear the things reported here. What would be the most significant mods to do to get even higher in sound quality, if you could choose and combine from:
1 -> shuntregging the VA supplies. (If I do this and prereg the shunts supply with the 2 LCBPS so that the dropout over the shunts is as small as possible, would heatsinking be required for the shuntregs? What is the required standing current here per channel for the + and - supplies?)
2 -> shuntregging the VD supply. (Same question here regarding heatsinking and preregging as above.)
3 -> Insering a shuntreg for the VACC and doing away with the buffering op-amps.
My case is a compact build in a ventilated case (modushop case: Galaxy, 230*280*40 mm).
The shuntregs I have in mind here are (of course) Pauls shunts.
I'd be very grateful for any help/guidance with this, thanks in advance.
/Magnus G.
I have a Buf32s powered by LCDPS + 2*LCBPS using 3* 15 VA trafos supplied by TPA. I love the sound coming out, but being a diyer, temptation is hard to resist when I hear the things reported here. What would be the most significant mods to do to get even higher in sound quality, if you could choose and combine from:
1 -> shuntregging the VA supplies. (If I do this and prereg the shunts supply with the 2 LCBPS so that the dropout over the shunts is as small as possible, would heatsinking be required for the shuntregs? What is the required standing current here per channel for the + and - supplies?)
2 -> shuntregging the VD supply. (Same question here regarding heatsinking and preregging as above.)
3 -> Insering a shuntreg for the VACC and doing away with the buffering op-amps.
My case is a compact build in a ventilated case (modushop case: Galaxy, 230*280*40 mm).
The shuntregs I have in mind here are (of course) Pauls shunts.
I'd be very grateful for any help/guidance with this, thanks in advance.
/Magnus G.
Buffalo reg mods
Hi Agent Cooper,
The mini shunt reg replacements for three terminal regs are not able to cope with the heat generated by the supply requirements for VA +/- 15 volt supplies. The Z1A/Z1N are the current favourites to use with these rails. You may not have the room for these in your case.
The VD + 5 volt supply needs to supply around 250ma to supply the two Z1703v3 shunt regs and the S1701v2LN series reg modifications. You will need to use the Z1A shunt reg for this level of power delivery. This will have to increase (easily done by changing one resistor on the PCB) to around 450ma if you also plan to remove the opamps used for Avcc and replace them with the Z17 shunt regs.
All the rest of the regs can be the mini shunt regs.
The Z1A/Z1N modules measure L x 62mm, W x 42mm, H (including 6mm for mounting pillars) x 33mm. This includes the on board heatsinks. Shunt regs are not very thermally efficient
as they operate rather like Class A amplifiers. 
Can you post some photos as it will help to see how much room you have available.
Regards
Paul
Hi Agent Cooper,
The mini shunt reg replacements for three terminal regs are not able to cope with the heat generated by the supply requirements for VA +/- 15 volt supplies. The Z1A/Z1N are the current favourites to use with these rails. You may not have the room for these in your case.
The VD + 5 volt supply needs to supply around 250ma to supply the two Z1703v3 shunt regs and the S1701v2LN series reg modifications. You will need to use the Z1A shunt reg for this level of power delivery. This will have to increase (easily done by changing one resistor on the PCB) to around 450ma if you also plan to remove the opamps used for Avcc and replace them with the Z17 shunt regs.
All the rest of the regs can be the mini shunt regs.
The Z1A/Z1N modules measure L x 62mm, W x 42mm, H (including 6mm for mounting pillars) x 33mm. This includes the on board heatsinks. Shunt regs are not very thermally efficient
as they operate rather like Class A amplifiers. Can you post some photos as it will help to see how much room you have available.
Regards
Paul
Thanks Paul,
I don't have pics of the build available online yet, but I can tell you right now that with the current build anything except mini shunt 3-pin reg replacements are out of the question. Ok, my mate has placed an order for a Buffalo kit with all Placid regs. Will probably get back to you when I have heard his and feel the urge to take my neat little build apart.....
Cheers
Magnus
I don't have pics of the build available online yet, but I can tell you right now that with the current build anything except mini shunt 3-pin reg replacements are out of the question. Ok, my mate has placed an order for a Buffalo kit with all Placid regs. Will probably get back to you when I have heard his and feel the urge to take my neat little build apart.....
Cheers
Magnus
Hi Magnus
The Z1A and Z1N reg boards are considerably smaller than the LCDPS and LCDPS boards (which are 84 x 51 mm). You could replace the LCDPS with a Z1A, and the pair of LDBPS's with a Z1A and a Z1N. OK, this would mean that both analogue channels used a common supply, but I'd be amazed if you didn't hear a big improvement nonetheless. In addition, you could fit appropriatethree legged regs directly to the board as Nic and Leo have done
Paul
The Z1A and Z1N reg boards are considerably smaller than the LCDPS and LCDPS boards (which are 84 x 51 mm). You could replace the LCDPS with a Z1A, and the pair of LDBPS's with a Z1A and a Z1N. OK, this would mean that both analogue channels used a common supply, but I'd be amazed if you didn't hear a big improvement nonetheless. In addition, you could fit appropriatethree legged regs directly to the board as Nic and Leo have done
Paul
Hi
It would be trivial to install rectifiers and a simple CRC filter before the Z1* boards (BTW I always use offboard transformers these days)
No comparisons. I'm using a PH PR3G reg for the combined digital supply, but just LCDPS's for the analogue supplies (though I have 3.3V Z17's on VACC). Eventually I'll try PR3G annd the negative equivalent (not available at the moment)on the analogue supplies
The regulatory performance of any of the PH regs is in a different league to a 317 or even the much superior Placid supply. Whether this makes any difference in practice in this application I have yet to hear (though it has with a vengence in other applications)
Paul
It would be trivial to install rectifiers and a simple CRC filter before the Z1* boards (BTW I always use offboard transformers these days)
No comparisons. I'm using a PH PR3G reg for the combined digital supply, but just LCDPS's for the analogue supplies (though I have 3.3V Z17's on VACC). Eventually I'll try PR3G annd the negative equivalent (not available at the moment)on the analogue supplies
The regulatory performance of any of the PH regs is in a different league to a 317 or even the much superior Placid supply. Whether this makes any difference in practice in this application I have yet to hear (though it has with a vengence in other applications)
Paul
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