Leo,
Where did you connect the PH substitutes for the LT1763's. In place of the decoupling caps (after removing the LT's), as I did, or did you mount them on the LT pads maintaining the coupling caps? A close-up side-view photo maybe🙂
You still have power on the µC after your mod?
Thanks,
Nic
Where did you connect the PH substitutes for the LT1763's. In place of the decoupling caps (after removing the LT's), as I did, or did you mount them on the LT pads maintaining the coupling caps? A close-up side-view photo maybe🙂
You still have power on the µC after your mod?
Thanks,
Nic
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Hi Nic
I desoldered and lifted up the output pins of the LT1763's, the output and ground of the PH regs are soldered directly onto the LT1763 output ceramics (C11,C17,C19)
VD+ input is no longer connected , the inputs of the PH regs runs straight to the 5v pre reg output (red wire running to each of the PH regs inputs) , the ground of 5v pre reg runs to VD ground
Cheers,
Leo
I desoldered and lifted up the output pins of the LT1763's, the output and ground of the PH regs are soldered directly onto the LT1763 output ceramics (C11,C17,C19)
VD+ input is no longer connected , the inputs of the PH regs runs straight to the 5v pre reg output (red wire running to each of the PH regs inputs) , the ground of 5v pre reg runs to VD ground
Cheers,
Leo
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Hi Leo
I've only had my Buffalo 32S for a few weeks- and for most of that time it was wrecked! I had to replace both thee ES9018S and one of the op amps after a series of idiotic mistakes I'd like to forget!
Like you, I've had great results using Paul Hynes' regs, which I've used, together with a number of other modifications, to bring the sound quality of a DIY Paradise NOS Monica 3 DAC (TDA1545A) up to an unbelievable level, and I'm keen to repeat the trick with the Buffalo
I think you now use 3.3V Z17 shunts to supply L and R VACC? Did you connect them directly, or did you leave the RC filter and op amp buffer circuits in place?
What type are the SMD caps originally fitted to the VACC supplies? And elsewhere? I assumed they were COG ceramics, but saw some talk of them being film types? I've used Panasonic ECPU SMD film caps in a similar application with grest success, and have in fact fitted them- 0u1 in parallel with a 47u BG NX HiQ- to the VACC supplies. I've also fitted the shunt regs, and removed the buffers
In some ways, Buffalo now bests Monica- but not in all! I think, overall, I still prefer Monica. But, the nature of the difference makes me think that regs all round will alter this
In the longer term, the I/V stage will have to go. I my recently have started using mixed triode/FET amplifier circuits, but op amps are still against my religion!
Best wishes
Paul
I've only had my Buffalo 32S for a few weeks- and for most of that time it was wrecked! I had to replace both thee ES9018S and one of the op amps after a series of idiotic mistakes I'd like to forget!
Like you, I've had great results using Paul Hynes' regs, which I've used, together with a number of other modifications, to bring the sound quality of a DIY Paradise NOS Monica 3 DAC (TDA1545A) up to an unbelievable level, and I'm keen to repeat the trick with the Buffalo
I think you now use 3.3V Z17 shunts to supply L and R VACC? Did you connect them directly, or did you leave the RC filter and op amp buffer circuits in place?
What type are the SMD caps originally fitted to the VACC supplies? And elsewhere? I assumed they were COG ceramics, but saw some talk of them being film types? I've used Panasonic ECPU SMD film caps in a similar application with grest success, and have in fact fitted them- 0u1 in parallel with a 47u BG NX HiQ- to the VACC supplies. I've also fitted the shunt regs, and removed the buffers
In some ways, Buffalo now bests Monica- but not in all! I think, overall, I still prefer Monica. But, the nature of the difference makes me think that regs all round will alter this
In the longer term, the I/V stage will have to go. I my recently have started using mixed triode/FET amplifier circuits, but op amps are still against my religion!
Best wishes
Paul
Hi Paul,
Problem with SMD, it makes replacing blown parts far more fiddly😀
I've been lucky so far although I had one small accident with the original Buffalo which I managed to sort out
BTW give it lots of run in time, those solid state Polymer capacitors sound shite for quite a while, they seem to get a lot better
Buffalo32s in stock form and using LM317/337 regulated supplies was pretty good but since fitting Pauls regs its doing some things better than any other dac I've heard.
Dustin hinted because the Sabre was maximised in one area downside being it made the PSRR of the chip lower , the reg quality used has a far greater influence than a lot of other dacs .
Saying that though the op-amps used in the output stage have very good PSRR and the PH regs made a very worthwhile improvement there too (I've tried a few various types there already)
I also have a Monica3, it currently uses ALW super regs, a few mods etc.
Monica3 should be next for fettling although I'll be amazed if it betters how this Buffalo32s currently sounds, NOS still has its limitations so it should be interesting doing more comparisons
I've not removed the AVCC L&R buffers on the Buffalo32s yet (I did on the original Buffalo) it may be something I look into next
Ideally I'd like a schematic for the Buffalo32s, what I may do is work it out and draw it, its a little harder with SMD
When you say VACC do you mean AVCC L & R for the Sabre chip? C1 and C2 directly on AVCC dac chip pins look to be ceramic, the others for the op-amps IVYII and voltage buffers look to be PPS films (the grey/white coloured ones)
I used BG N in the M3 but may replace them with something else, I find they add too much of a certain signature , to my ears its a similar thing as what Valves do too , nothing wrong in that but I think it can shove things the wrong way, to my ears anyway🙂
Only BG's I've been really impressed with are FK used on digital supplies
At the moment I much prefer Buffalo32s, I've not heard any track yet where I feel the M3 betters it, I also so far prefer AYAII over M3.
I'm hoping to do a lot more work on the M3 soon including trying Pauls regs with it
I think we'll be struggling to beat something like the OPA1632's by discrete but I'll certainly be up for giving things a try to compare, not sure what yet.
I'll use the original Buffalo as a guinnea pig first before hacking at the Buffalo32s, Doubt I'll use anything valve based though with a chip like the Sabre🙂
BTW it would be nice to start another thread for Monica3 , share a few idea's etc
Cheers,
Leo
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Hi Leo
Yes I meant AVCC
If you check out the DIY Paradise forum you'll find details of Monica's evolution, in which I was heavily involved
Paul
Yes I meant AVCC
If you check out the DIY Paradise forum you'll find details of Monica's evolution, in which I was heavily involved
Paul
Hey, Leo, needsp, my recent experiments with transformer DAC outputs confirm what others have said who have tried this - it's a definite improvement! On my Vout PCM1793 DAC which had previously used a op-amp for some gain & LPF duties, it's a definite improvement. You know Wavelegth use a transformer output on their incarnation of the Sabre DAC
I'm wondering if the same would be noted on the Sabre.
Cost of transformers - I got a pair of Sescom MI-97 for $50 on ebay (haven't received them yet), I have some Lundahl LL1517s that I'm trying to get the best out of and I have some other transformers that are earmarked for a pre-amplifier, that sound stunning.
Cost-wise, cheaper than any Buffalo o/p stage - worth a try?!
Leo, did you ever try the Simple Salas Shunt? I'd be interested to hear how it stacked up against the PH regs?
I'm wondering if the same would be noted on the Sabre.
Cost of transformers - I got a pair of Sescom MI-97 for $50 on ebay (haven't received them yet), I have some Lundahl LL1517s that I'm trying to get the best out of and I have some other transformers that are earmarked for a pre-amplifier, that sound stunning.
Cost-wise, cheaper than any Buffalo o/p stage - worth a try?!
Leo, did you ever try the Simple Salas Shunt? I'd be interested to hear how it stacked up against the PH regs?
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I've not tried output transformers with the Sabre dacs yet, if I can find something suitable I may try it with the original Buffalo first
Sorry but I didn't get round to trying the Salas shunt yet because I just went ahead and replaced the LT1763's which the separate regged 5v PSU feeds
Sorry but I didn't get round to trying the Salas shunt yet because I just went ahead and replaced the LT1763's which the separate regged 5v PSU feeds
Hi Leo
I asked Twisted Pear about the nature of the chip SMD caps on the Buffalo 32S board. Brian replied-
"All of the caps on the Buffalo32 are ceramic. Values <= 0.1uF are C0G. Values > 0.1uF are X7R 5%. We tried several types in different positions before settling on what we have. The CoG caps have the lowest ESR, best stability, and lowest leakage. They also sounded the best. "
Paul
I asked Twisted Pear about the nature of the chip SMD caps on the Buffalo 32S board. Brian replied-
"All of the caps on the Buffalo32 are ceramic. Values <= 0.1uF are C0G. Values > 0.1uF are X7R 5%. We tried several types in different positions before settling on what we have. The CoG caps have the lowest ESR, best stability, and lowest leakage. They also sounded the best. "
Paul
Hi Paul,
I'm sure it used to say on the site PPS caps was fitted🙂 anyway thanks for clearing that up
Cheers,
Leo
Hi Nic
If it sounds ok and theres no ringing caused by the leads I wouldn't worry tbh
According to the above post from Paul they used X7R 5%, smd ceramics usually come in packs/strips of say 10, 50 etc but are not usually expensive
Cheers,
Leo
The buffer guarantees a very very low impedance and adds close to 0 noise. I don't see much point in removing it. Just my 2 cents.
I removed the buffers and ran separate PH shunts with very low output impedance directly to AVCC L&R
As Brian already mentioned the onboard buffers are very good as is but I wanted to try it anyway😀 after listening tests this proved to be a worthwhile mod, sounded less digital
Thanks Brian, BTW Buffalo32s is sounding wonderful so far, ignore certain other persons trying to flame it😉
i tried using seperate sigma11 supply for avcc in my buffalo 1.2 and didnt notice any real significant change. a big improvement was seen when i remove the 3.3v ldo and feed directly with a sigma11. i must admit though that at 3.3V the sigma is probably not regulating very well, but still...
just wanted to share my experience so far
just wanted to share my experience so far
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OK Guys here is fun little mod that works well.
Do this at your own risk. Mods are not supported period. 🙂 But they are fun. So if your hip, then go for it.
First to do it you need a fairly clean stiff regulator into VA+ and VA-. LCBPS is just fine. Placid even better.
Next you need to set those to 15V. (probably there already).
Now Grab a metal film 390R 1/2W resistor.
Connect one end to +15V and the other to AVCC(at the bypass cap).
You now have a good constant current source feeding the AVCC input just a tad more than it really needs, which the opamp will nicely dispose of the excess to keep at the reference voltage(3.3VDC). The opamp on AVCC now is a shunt element, or rather the combination is a whole local shunt regulator. The opamp is also now having to do a lot less work, making it work better.
Yes the resistor will get pretty warm. This is normal.
Now you have a shunt regulated AVCC supply. 🙂
Will you hear a difference??? I have no idea.
I found it pleasant.
As always have fun.
PS, yes you could use a CCD, JFET, or any other current source will work well (some better than others). You will want about 30-35ma per channel.
Cheers!
Russ
Do this at your own risk. Mods are not supported period. 🙂 But they are fun. So if your hip, then go for it.
First to do it you need a fairly clean stiff regulator into VA+ and VA-. LCBPS is just fine. Placid even better.
Next you need to set those to 15V. (probably there already).
Now Grab a metal film 390R 1/2W resistor.
Connect one end to +15V and the other to AVCC(at the bypass cap).
You now have a good constant current source feeding the AVCC input just a tad more than it really needs, which the opamp will nicely dispose of the excess to keep at the reference voltage(3.3VDC). The opamp on AVCC now is a shunt element, or rather the combination is a whole local shunt regulator. The opamp is also now having to do a lot less work, making it work better.
Yes the resistor will get pretty warm. This is normal.
Now you have a shunt regulated AVCC supply. 🙂
Will you hear a difference??? I have no idea.
I found it pleasant.
As always have fun.
PS, yes you could use a CCD, JFET, or any other current source will work well (some better than others). You will want about 30-35ma per channel.
Cheers!
Russ
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