Hi Richard/all
I made a simple working document to realise what the 'maxed out' version of the board would incorporate, please anybody check it out & add feedback.
As I only have 1 channel and its quite hard to source a new chip locally, from a reliable seller, I am highly motivated to lock down the new design so I can order some new boards : )
@Grarea let us know if you need support with any words, happy to help, yeghes da.
I made a simple working document to realise what the 'maxed out' version of the board would incorporate, please anybody check it out & add feedback.
As I only have 1 channel and its quite hard to source a new chip locally, from a reliable seller, I am highly motivated to lock down the new design so I can order some new boards : )
@Grarea let us know if you need support with any words, happy to help, yeghes da.
Correct, that's it exactly.
I did have R21 fitted, so I removed those. It is an improvement, but still not down to acceptable levels. Maybe it has something to do with my layout? I didn't try DAC -> amps on the bench before putting it in a case, so I don't have that for comparison. I was trying to make everything fit into a repurposed tape drive enclosure so I could send it to my dad to try out. Here is the layout for reference.
Attachments
One thing I noticed is that the polarity of one of your audio channels out of the DAC is swapped. On the Deca DAC output both the centre pins are 0V but you have a yellow wire going to one centre pin and its partnering black wire going to the signal pin. I doubt very much if that's the cause of your troubles though.
To check if you're getting coupling from the PSUs to the input trafos, you could remove the wires between DAC and amps and short the input terminals on the amps. If the amps are quiet it won't be magnetic pick-up.
To check if you're getting coupling from the PSUs to the input trafos, you could remove the wires between DAC and amps and short the input terminals on the amps. If the amps are quiet it won't be magnetic pick-up.
@Shertzy/Jules
I'm scrolling through your pdf. Good to have an offline document for this, thanks. I have no pdf writer so I'll post comments here.
Transformers - we don't have any reason for including the original custom trafos in the 'taken to 11' version. Cinemag will be one option, another option will be some Taobao EE25 permalloy trafos (I think I've already linked these somewhere earlier on this thread or on the original technical thread). We might also investigate a screening can for these, if available.
Caps - if we're gilding the lily then 3300uF can probably be increased in value. I have some 15,000uF Panasonics which are 22mm diameter which will be worth trying. Do you have examples of brands of snap-ins which you want to try? Output caps I'll also want to try multiple (7 off) parallel NP0 ceramics to achieve the lowest possible loss factor. No need for the original polyesters.
Regulators - I'll do some more exploration into best possible regulation and noise, primarily for the LM317 replacement.
Inductors - I was going to suggest Coilcraft SER1390, the drawings you have look quite similar to that.
Overall my initial aim is to keep this within 10*10cm if possible so as not to blow a significant portion of the budget on the PCB itself.
I'm scrolling through your pdf. Good to have an offline document for this, thanks. I have no pdf writer so I'll post comments here.
Transformers - we don't have any reason for including the original custom trafos in the 'taken to 11' version. Cinemag will be one option, another option will be some Taobao EE25 permalloy trafos (I think I've already linked these somewhere earlier on this thread or on the original technical thread). We might also investigate a screening can for these, if available.
Caps - if we're gilding the lily then 3300uF can probably be increased in value. I have some 15,000uF Panasonics which are 22mm diameter which will be worth trying. Do you have examples of brands of snap-ins which you want to try? Output caps I'll also want to try multiple (7 off) parallel NP0 ceramics to achieve the lowest possible loss factor. No need for the original polyesters.
Regulators - I'll do some more exploration into best possible regulation and noise, primarily for the LM317 replacement.
Inductors - I was going to suggest Coilcraft SER1390, the drawings you have look quite similar to that.
Overall my initial aim is to keep this within 10*10cm if possible so as not to blow a significant portion of the budget on the PCB itself.
Richard and Jules.
I was getting back into this project and was going to order a pair. Nautibuoy (Ray) wasn't sure if he may order another pair so I held off until we knew a confirmed order for the UK. In the meantime I'm reading about this hot rodded version. I could be interested.
Trafos.....what about asking Bisesik? I know his dac output trafos are highly regarded. I have no idea if they are suitable here or even if they would perform better than the ones you propose. I wouldn't be 'in' for Cinemags or Bisesik unfortunately, more likely the best that Richard could offer.
Richard do you have stock of amp ic? I don't see many with 'nxp' branding on AliExpress. Dont know if these are 'safe'. Looking ahead to this projects sustainability.
Regards 10x10 pcb. Could we have 2 boards with the output filter L and C on a smaller separate board? Have used the Coilcraft on my JLE 3255. Are they the same footprint as the Wurth? Look very similar.
Lm317....maybe a small 'denoiser' type setup? Or i have had good success with the Aliexpress TPS7A4700 type 3 pin 780x regs. I think they are mega low impedance but not necessarily the lowest noise.
Richard you have probably forgotten more on all of this than I know so please take all this as you will, I was just adding to the brainstorming! ...I can't edit the pdf either atleast from my phone.
Regards
Jim
I was getting back into this project and was going to order a pair. Nautibuoy (Ray) wasn't sure if he may order another pair so I held off until we knew a confirmed order for the UK. In the meantime I'm reading about this hot rodded version. I could be interested.
Trafos.....what about asking Bisesik? I know his dac output trafos are highly regarded. I have no idea if they are suitable here or even if they would perform better than the ones you propose. I wouldn't be 'in' for Cinemags or Bisesik unfortunately, more likely the best that Richard could offer.
Richard do you have stock of amp ic? I don't see many with 'nxp' branding on AliExpress. Dont know if these are 'safe'. Looking ahead to this projects sustainability.
Regards 10x10 pcb. Could we have 2 boards with the output filter L and C on a smaller separate board? Have used the Coilcraft on my JLE 3255. Are they the same footprint as the Wurth? Look very similar.
Lm317....maybe a small 'denoiser' type setup? Or i have had good success with the Aliexpress TPS7A4700 type 3 pin 780x regs. I think they are mega low impedance but not necessarily the lowest noise.
Richard you have probably forgotten more on all of this than I know so please take all this as you will, I was just adding to the brainstorming! ...I can't edit the pdf either atleast from my phone.
Regards
Jim
Jim - I do have a small cache of TDA8932 and I also have a ZIF-socketed test board for testing the chip so I could become a source of chips if there's demand for 'approved' ICs. It seems they're easily available on Taobao still. I'd be willing to take a punt that those on Aliexpress are good enough, after all they're only about $1 each in batches of 10.
Putting the caps on an external board means no low-inductance grounding route will be available so a bit less than ideal. Let's wait and see how much real estate we need to use on the PCB.
Good idea about the denoiser (taking you mean Elvee's enhanced regulator) - I shall give that a spin.
All contributions to the brainstorm gratefully received. Bisesik trafos would need to be custom I think, I've not looked into how big they are.
Putting the caps on an external board means no low-inductance grounding route will be available so a bit less than ideal. Let's wait and see how much real estate we need to use on the PCB.
Good idea about the denoiser (taking you mean Elvee's enhanced regulator) - I shall give that a spin.
All contributions to the brainstorm gratefully received. Bisesik trafos would need to be custom I think, I've not looked into how big they are.
I'm suggesting the 'entry level' trafos be these ones : https://item.taobao.com/item.htm?sp...8FU3W&id=645973454585&ns=1&abbucket=20#detail
Price under $10 each and plenty of primary inductance (300H+ for the lowest sensitivity) so can couple easily via film caps to keep out DC.
Price under $10 each and plenty of primary inductance (300H+ for the lowest sensitivity) so can couple easily via film caps to keep out DC.
Hello,.
I built a Richard amplifier and I like it a lot because it sounds good, it's simple, fun to build and has a low cost. I would like the new version to improve and keep the same features. I use the Denoiser and it works well. It would be nice to include a type filter as well:
https://www.diyaudio.com/community/threads/gb-aca-power-supply-filter-kits.376245/What do you think about?
Regards
Guglielmo
I built a Richard amplifier and I like it a lot because it sounds good, it's simple, fun to build and has a low cost. I would like the new version to improve and keep the same features. I use the Denoiser and it works well. It would be nice to include a type filter as well:
https://www.diyaudio.com/community/threads/gb-aca-power-supply-filter-kits.376245/What do you think about?
Regards
Guglielmo
Hi Guglielmo - you'd like us to include a filter for removing HF hash from SMPSUs? Yeah good idea, I will have a think about that.
Incidentally related to this amp, I'm currently working on an input/buffer board with volume control. So that'll allow you to build an integrated amp (no source switching though, that'll come later if there's demand) with a single input with volume control. So say you wanted to create a system with just DAC and AMP and didn't want to use digital volume before the amp, this board would suit, along with two monoAMPs and a switching supply. The buffer board has its own linear PSU so doesn't defeat the transformer's function of blocking common-mode noise from the SMPSU.
Incidentally related to this amp, I'm currently working on an input/buffer board with volume control. So that'll allow you to build an integrated amp (no source switching though, that'll come later if there's demand) with a single input with volume control. So say you wanted to create a system with just DAC and AMP and didn't want to use digital volume before the amp, this board would suit, along with two monoAMPs and a switching supply. The buffer board has its own linear PSU so doesn't defeat the transformer's function of blocking common-mode noise from the SMPSU.
Hi Richard,Jim,all,
I am loving the brainstorming
and the "turn to 11" version title.
Reg - For the 317 reg, the Sparkos, while pricey are superb, would it be possible to have the choice of using it or a denser circuit for comparison, that would be most radical?
Caps - the larger electros is certainly welcome for trialing, I like Epcos, Panasonic, Elna, potentially even Audio Note Kaisei (developed by Rubicon as an improved replacement for black gates, they are great but super pricey & cumbersome) depends on the PCB real estate we realistically have with 10x10, I actually really like the fact that the boards are so small, it leaves so many mounting options and integrated possibilities.
The output caps - is it possible to include both film options (the Duelund absolutely rock) and the the ceramic rows, to test between them, or is there too much going on to incorporate both avenues? The film caps could be placed very close to edges so they "hang half off", with some silicone adhesive they should be solid with only half contact?
Transformers - I am pretty hellbent on Cinemags, if I ever receive a reply, 3 emails down now. Many recordings have either been recorded or mastered through gear containing Cinemags, so I feel like its an interesting choice, well overrated & provides 3db more sound, which is true 'turn to 11' stylee.
The reason for including your custom input transformer holes Rich, was based on curiosity, in the back of my mind I am wondering if your custom types are even better than the pro audio types, but naturally that is overboard to include both options for a small run production PCB, isn't it? Maybe? Possibly?
Inductors - yes, the Coilcrafts I believe have the same package types, I tried to find the package type name/code but nothing showed up. Others in the class d forums have tried both Coilcraft and Wurth and mentioned Wurth to be the better sounding of the 2, at the output It is reasonable to believe in slight sonic differences.
Exciting stuff!
I am loving the brainstorming
and the "turn to 11" version title.Reg - For the 317 reg, the Sparkos, while pricey are superb, would it be possible to have the choice of using it or a denser circuit for comparison, that would be most radical?
Caps - the larger electros is certainly welcome for trialing, I like Epcos, Panasonic, Elna, potentially even Audio Note Kaisei (developed by Rubicon as an improved replacement for black gates, they are great but super pricey & cumbersome) depends on the PCB real estate we realistically have with 10x10, I actually really like the fact that the boards are so small, it leaves so many mounting options and integrated possibilities.
The output caps - is it possible to include both film options (the Duelund absolutely rock) and the the ceramic rows, to test between them, or is there too much going on to incorporate both avenues? The film caps could be placed very close to edges so they "hang half off", with some silicone adhesive they should be solid with only half contact?
Transformers - I am pretty hellbent on Cinemags, if I ever receive a reply, 3 emails down now. Many recordings have either been recorded or mastered through gear containing Cinemags, so I feel like its an interesting choice, well overrated & provides 3db more sound, which is true 'turn to 11' stylee.
The reason for including your custom input transformer holes Rich, was based on curiosity, in the back of my mind I am wondering if your custom types are even better than the pro audio types, but naturally that is overboard to include both options for a small run production PCB, isn't it? Maybe? Possibly?
Inductors - yes, the Coilcrafts I believe have the same package types, I tried to find the package type name/code but nothing showed up. Others in the class d forums have tried both Coilcraft and Wurth and mentioned Wurth to be the better sounding of the 2, at the output It is reasonable to believe in slight sonic differences.
Exciting stuff!
Hi Richard. After something of a hiatus I'll have a look at debuggimg my amp boards over the Christmas break. As Jim mentioned, I'm thinking about buying another pair of boards from you to use in a 'second room' system with a MiniDSP active crossover, assuming I can get my current boards working and, if I can't, as a pair of replacements. That said, I'm also interested in the possibility of a hot-rodded version as per the ongoing discussion here. I think I'll keep my powder dry until I know the situation with the boards I already have. Keep up the good work on the DACs and amps.
Ray
Ray
Just thinking out loud Richard. I still have a couple of digital amp boards that I bought pack along, when you were using them to experiment with them for headphone amps - I started to modify one as per your blog so I should dig out the information and resurect the project. One of the things I started to explore was the ability of the amp chip on those boards (I must look up the desgnation as I can't read it from the chip) to accept an I2S input so it would in essence become a power DAC. Have you considered a take on that, it would certainly be of interest to me, especially in the sort of context I mention in my previous post?
Ray
Edit: Just looked it up and the boards I have use the STA333BW amp chip - there seem to be a lot of them available from China on ebay - I must check out the datasheet again and find your blogs and threads on the HPA use.
Ray
Edit: Just looked it up and the boards I have use the STA333BW amp chip - there seem to be a lot of them available from China on ebay - I must check out the datasheet again and find your blogs and threads on the HPA use.
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