I was wondering about this given the initial choice of bipolar by BRZ3255 with their JRC5532 (if I am correct this is bipolar)!Hello again
Regarding operational amplifiers, a little reminder:
- The bipolar OPAMPS are designed for resistances at their inputs less than or equal to 3KOhms maximum because after their 'voltage noise spectral density' rises steeply!
- THE FET OPAMPS are designed for resistances at their inputs greater than or equal to 3KOhms because their performance in terms of 'voltage noise spectral density' is no longer impacted afterwards.
I give you the comparative table of TEXAS INSTRUMENTS ->
View attachment 280808
Yes, ICIETDIYEUR has done a thorough job there and I am also better for reading about his work. Funny you should mention Rod Rain as I have had a dac in the past from Rod Rain that was superb value for money but I sadly received a faulty unit and while it last only 10 minutes before the sound quality disappeared into an horrendous crunching sound it was actually very nice. I don't think it was a mark against Rod Rain as the seller was really surprised at the failure of the unit and they have sold over a 1000 units since with no issues. I will have a look at HIDI D10 later.Hello @Schlippwhip68
Your experience is very similar to mine with the op amps, only in my case I had a pair of OPA1656 vs your Muses 8820. With regard to the decouplers, because I just put them in and left them there I really should take them out, and then put them back to really assess. Perhaps when yours come I will do this and compare. Your experience with the Muses 8820 makes me think that I should try the Muses 02 I have. I might do this over the weekend.
Overall this amp is a step up for me from the Aiyimas (07, 08) in clarity, muscularity and control, and running it with the volume contrul on maximum, but with a lossless volume control DAC upstream like v1adpetrov2 said: DAC SMSL D300, works very well. I use a Rod rain audio HIFI DA10 recommended by ICIETDIYEUR and I find it excellent. I also use passive balanced dual mono volume controls, and these are excellent also (a bit unconventional but I find it very useful). Also a balanced switch box here.
Bad News: The sad sort of random flinging of parts without much target or understanding, much less any validation*, then lots of hand-waving fairy tales, which characterize far too much of DIY audio and have no business on a technical/scientific forum.
Good News: It kept people off the streets and out of trouble. And at least one person blew up his stuff, an object lesson for why this sort of random parts-flinging is a really bad idea for anything other than keeping people distracted.
*Well, one guy had some scope traces which may or may not have had much meaning.
Yes, particularly his documents and input on the op amps in this BRZ configuration. It still does not explain the conundrum of the original design using bipolar, but with fets possibly being a better match - but it does introduce people like me to the scientific side!Yes, ICIETDIYEUR has done a thorough job there and I am also better for reading about his work. Funny you should mention Rod Rain as I have had a dac in the past from Rod Rain that was superb value for money but I sadly received a faulty unit and while it last only 10 minutes before the sound quality disappeared into an horrendous crunching sound it was actually very nice. I don't think it was a mark against Rod Rain as the seller was really surprised at the failure of the unit and they have sold over a 1000 units since with no issues. I will have a look at HIDI D10 later.
I have rigged a balanced connection this morning using newly acquired Belden 8402/Neutrik connects. The sound is definitely cleaner but I am also running a DBX 231s EQ directly into this amp amd the Topping E50 is feeding the DBX from the Mac. Interestingly the RCA connection using the same set up is on average 1/3 louder...?....but the XLR is better sound quality. I am going to take a deeper look into BRZHIFI as I am looking for a balanced preamp. Its also nice to see BRZHIFI have used Neutrik XLR on this 3255XLR amp, another point for good quality that they don't mention in the sales listing surprisingly enough. But anyway this is a good amp and I like it, I will be interested to hear back from you once you try the Muses02. I really like the 8820d. I also have the A07, good little amp. The footprint on BRZHIFI is a bit of sweet spot for me personally as it gives me the room to stack it easily unlike the A07. Incidentally Aiyima have just released an upgraded A04 with 3.5mm jack out.
I am: it has made our streets marginally safer and less crowded.Don't be sad, be happy
I note that you are currently off the streetsI am: it has made our streets marginally safer and less crowded.
It is an absolute case study.Look I get what you are saying, I am on ASR because of the silliness / snakeoil etc. elsewhere in HIFI, but I don't think things have gone the way you describe on this thread.
Answer my links and my question about power supplies please.It is an absolute case study.
Pavel would be a better source. Unlike the folks on this thread, he states a specific problem to be fixed, documents it, fixes it, and documents the results of the fix.Answer my links and my question about power supplies please.
I'm not sure about Pavel ... but I agree about a change intended as an improvement being measured before and after. These amplifiers are so inexpensive, a comparator model should be possible to provide. I have been looking at doing exactly this.Pavel would be a better source. Unlike the folks on this thread, he states a specific problem to be fixed, documents it, fixes it, and documents the results of the fix.
Yep, always better to choose the right shoes to go dancing in.Bad News: The sad sort of random flinging of parts without much target or understanding, much less any validation*, then lots of hand-waving fairy tales, which characterize far too much of DIY audio and have no business on a technical/scientific forum.
Good News: It kept people off the streets and out of trouble. And at least one person blew up his stuff, an object lesson for why this sort of random parts-flinging is a really bad idea for anything other than keeping people distracted.
*Well, one guy had some scope traces which may or may not have had much meaning.
I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.I'm not sure about Pavel ... but I agree about a change intended as an improvement being measured before and after. These amplifiers are so inexpensive, a comparator model should be possible to provide. I have been looking at doing exactly this.
What is interesting about this amplifier for me, is that it is balanced, and runs much cooler than the Aiyima A07 and especially the A08 amplifiers. The latter runs way too hot for me in summer ... so I was drawn to this model to run my balanced phono stage into.
On this thread there is a modification to the power supply which increases the voltage and power, and then there are modifations to accomodate this change. I am not sure that I need more power, but I am sure it is readily audible.
Then there is a suggested op amp replacement to FETs - because of the "unity gain buffer configuration". I think A/B testing is interesting and "allowed" on this. I certainly found this interesting to do a controlled swap ... does not take long and I did not blow myself up...
There could be really interesting debate on this last point, but, for me, I would be interested in seeking to achieve the kind of SINAD improvements (as per the threads I linked to) from an improved SMPS.
Furthermore, as you say, this change could be clearly measured. The links I made show exactly what could be measured (or what I would like to see).
And then I would like to be able to clearly hear an improvement. ... just need to find someone to do the SINAD etc. I am in France, and not really inclined to mailing a couple of these across the pond ...!
Then the ultimate point of this thread would be realized in my view.
Yes (clean swap), but look at the amp rating too - the original power supply was 36V / 9.5A @342W, it looked like the same SMPS actually as in the A08 ... but then BRZ had to change it as I presume parts supply became an issue. I think to another of the same rating.I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.
The jury is still out on changing the power supply as we discussed earlier but if i was too then i don't have the need to increase voltage from 36v, I prefer to remain there but PFC is noted as an advantage here and it is extra that quality that has my interest. I know this might sound like a rookie question but I have a better chance of learning here than anywhere else at present..especially a Bakery...so please correct me if I am wrong but staying with 36v and going with PFC will not require any further modification of other capacitors will it? It should be a clean swap...?
https://www.supercircuits.com/resources/tools/volts-watts-amps-converter I think !I am surprised as to how cool this amp actually runs. I have left the lid off until a few parts arrive and have been checking temps with balanced connection and volume around 11.00 o'clock, easily loud enough for a 5m x 5m room. After an hour or so the amp chips heatsink remained only slightly warm, much cooler than my A07 and A04 at the same levels. I certainly don't think there is any need to vent the box like i did with my A07. I then kept the lid on for a while and again very little heat.
The jury is still out on changing the power supply as we discussed earlier but if i was too then i don't have the need to increase voltage from 36v, I prefer to remain there but PFC is noted as an advantage here and it is that little extra quality that has my interest. I know this might sound like a rookie question but I have a better chance of learning here than anywhere else at present..especially a Bakery...so please correct me if I am wrong but staying with 36v and going with PFC will not require any further modification of other capacitors will it? It should be a clean swap...?
Thanks, the only one i can find with correct fit (Ali Express) and PFC so far under £50 is 36v 11A. How much 1.5A difference will make in the system is a mystery to me. I am 50% it won't be a problem as the power supply will either only pull or push only what it requires and so thew extra 1.5A is just a little extra dormant headroom...https://www.supercircuits.com/resources/tools/volts-watts-amps-converter I think !
So I am wondering about this one ... https://hifimediy.com/product/smps300r-38v-230v-power-supply/ it has much lower noise than that calculated originally by @v1adpetrov2 ... actually this one would not fit either (post edit)!!
Looking back I see that @v1adpetrov2 linked to this: https://www.aliexpress.com/item/1005001834039255.html - size?
yes ... page 5 ... , ICIETDIYEUR linked to this https://fr.aliexpress.com/item/1005....0.0.1d25378dOkgkWj&mp=1&gatewayAdapt=glo2fra
so it was looked at in theory, because of the noisy supply, but not tried as far as I know. The actual unit you can look up (at least on mine) is here: https://www.fs-czx.com/?kg/73.html
2. HIFIMEDIY power supply = SMPS300RS -> W=100mm / D=100mm /H=40mm - OVERSIZE!So I am wondering about this one ... https://hifimediy.com/product/smps300r-38v-230v-power-supply/ it has much lower noise than that calculated originally by @v1adpetrov2 ... actually this one would not fit either (post edit)!!
3. ADP power supply = A-D-P-40036-52 -> W=82mm / D=127mm /H=45mm - OVERSIZE!Looking back I see that @v1adpetrov2 linked to this: https://www.aliexpress.com/item/1005001834039255.html - size?
4. MEANWELL power supply = EPP-400-36 -> W=76,2mm / D=127mm /H=35mm - size is OK!!!yes ... page 5 ... , ICIETDIYEUR linked to this https://fr.aliexpress.com/item/1005....0.0.1d25378dOkgkWj&mp=1&gatewayAdapt=glo2fra