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Man, those look nice. Even $13 with opa1656s installed is a good deal.
Thanks for the link.
You're welcome... Just be careful with the inserts on the amp board. If you stretch them out the Brown dog inserts won't make full contact.
Pete
Pete
The KEMET C322C106K3R5TA caps are ceramic 10UF 25V X7, functionally similar to the SMD X7R caps used on the TI TPA3251EVM & TPA3255EVM board.
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Yes, Ceramic and Poly film are different. Typically ceramic is not maybe the most linear for audio signal path.
Film capacitor - Wikipedia
Ceramic capacitor - Wikipedia
What is a Film Capacitor and Different Types of Film Capacitors with Their Applications
Film capacitor - Wikipedia
Ceramic capacitor - Wikipedia
What is a Film Capacitor and Different Types of Film Capacitors with Their Applications
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Ceramics work well as as bypass cap, but they have high Q. Above resonance they become inductive. The capacitance can vary by the voltage across the ceramic dielectric (typically not the best for audio signal path).
This may be a pretty good background overview for you. One should read & try to understand the product datasheet of the components they choose.
"Dealing with Noise Using Capacitors
Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL
Measures to Address Noise Using Capacitors
Effective Use of Decoupling (Bypass) Capacitors Point 1
Effective Use of Decoupling Capacitors Point 2
Effective Use of Decoupling Capacitors, Other Matters to be Noted
Effective Use of Decoupling Capacitors, Summary"
This may be a pretty good background overview for you. One should read & try to understand the product datasheet of the components they choose.
"Dealing with Noise Using Capacitors
Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL
Measures to Address Noise Using Capacitors
Effective Use of Decoupling (Bypass) Capacitors Point 1
Effective Use of Decoupling Capacitors Point 2
Effective Use of Decoupling Capacitors, Other Matters to be Noted
Effective Use of Decoupling Capacitors, Summary"
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Quote: 4) Replaced the 4 opa caps nearest the heatsink (input caps?) with 10uf film caps
=> They are actualy the output caps of that OPA stage. They are the input caps to the power chip
5) Replaced the 5 opa caps with Nichicon UFG1E220MDM 22uf and bypassed the middle with .1uf TDK
=> That mod alone of the middle one probably counted for 50% of your entire cap mods around the OPA stage. Good you concentrated on that one adding 0.1uF.
All the other 8 caps could also benefit from that... slightly.
You haven't addressed though the OPA PS caps other than the 0.1uF bypass (which is already a good thing). We found more was needed there, we added a total of 20uF per OPA close to the each OPA's leg, consisting of a mix of X7R and 'lytics.
I understand you may not want to go SMD (OPA etc.), hence making it more difficult to tune the OPA PS caps other than with a tiny 0.1uF. Although the bypasses are best done in situ, when going for larger values you can accept to move somewhat away from the legs / havingslightly longer distances. By adressing the other caps you will have an effect on the OPA's PS similar than what we did, but not as good as not splitted etc. BUT that means that you should find more points on these other caps than we did... because you will gain some that related to what you would have had bypassing further the OPA's PS.
We went the opposite direction, to be cost effective: we addressed as far as we could each OPA's PS where it mattered the most (in situ) and then just bypassed midly the overall 12V PS to address whatever may be needed.
In you case you won't be able to address the OPA in isolation and you may have to blindly address all the caps until you find the one that is relevant to the OPA 12V feed. I didn't bother tracing which one(s) it is... as I didn't need to and we don't have the schematics of that section sadly.
Good luck for the remaining mods
Claude
PS: note that the Aiyima 04, even modded, is still cheaper than most other DIY or ready made boards options around that power chip. These MAY not offer really more sonic qualities and could even offer less if unknown quantities. I bought the 3rd Aiyima for 37E delivered and added 18E for the ready made SMPS they associated with it. But if having though some special LS impedance, having PFFB or the ability to chose from scratch the ouput filter can be benefical.
=> They are actualy the output caps of that OPA stage. They are the input caps to the power chip
5) Replaced the 5 opa caps with Nichicon UFG1E220MDM 22uf and bypassed the middle with .1uf TDK
=> That mod alone of the middle one probably counted for 50% of your entire cap mods around the OPA stage. Good you concentrated on that one adding 0.1uF.
All the other 8 caps could also benefit from that... slightly.
You haven't addressed though the OPA PS caps other than the 0.1uF bypass (which is already a good thing). We found more was needed there, we added a total of 20uF per OPA close to the each OPA's leg, consisting of a mix of X7R and 'lytics.
I understand you may not want to go SMD (OPA etc.), hence making it more difficult to tune the OPA PS caps other than with a tiny 0.1uF. Although the bypasses are best done in situ, when going for larger values you can accept to move somewhat away from the legs / havingslightly longer distances. By adressing the other caps you will have an effect on the OPA's PS similar than what we did, but not as good as not splitted etc. BUT that means that you should find more points on these other caps than we did... because you will gain some that related to what you would have had bypassing further the OPA's PS.
We went the opposite direction, to be cost effective: we addressed as far as we could each OPA's PS where it mattered the most (in situ) and then just bypassed midly the overall 12V PS to address whatever may be needed.
In you case you won't be able to address the OPA in isolation and you may have to blindly address all the caps until you find the one that is relevant to the OPA 12V feed. I didn't bother tracing which one(s) it is... as I didn't need to and we don't have the schematics of that section sadly.
Good luck for the remaining mods
Claude
PS: note that the Aiyima 04, even modded, is still cheaper than most other DIY or ready made boards options around that power chip. These MAY not offer really more sonic qualities and could even offer less if unknown quantities. I bought the 3rd Aiyima for 37E delivered and added 18E for the ready made SMPS they associated with it. But if having though some special LS impedance, having PFFB or the ability to chose from scratch the ouput filter can be benefical.
Quote: The KEMET C322C106K3R5TA caps are ceramic 10UF 25V X7, functionally similar to the SMD X7R caps used on the TI TPA3251EVM & TPA3255EVM board.
I am not a fan of X7R in the signal path. Definitely coloured. Annoying sound long term for me. You could bypass them with 0.1 C0G and see if you like the result. Taste and colours...
PPP or C0G caps are way better, be it as signal or DC caps. However, you won't have the right form factor abviously, or price, as all is trade off. I found X7R caps to be very acceptable in PS applications as bypass. If associated with 'Lytics and a C0G or PPP 0.1uF small bypass probably one gets very close to what a full PPP PS would give 🙂
Regarding the adapters, it would be good to have some where the top legs stand proud... it enabled us to easily solder the additional OPA PS bypasses we found benefical...
I am not a fan of X7R in the signal path. Definitely coloured. Annoying sound long term for me. You could bypass them with 0.1 C0G and see if you like the result. Taste and colours...
PPP or C0G caps are way better, be it as signal or DC caps. However, you won't have the right form factor abviously, or price, as all is trade off. I found X7R caps to be very acceptable in PS applications as bypass. If associated with 'Lytics and a C0G or PPP 0.1uF small bypass probably one gets very close to what a full PPP PS would give 🙂
Regarding the adapters, it would be good to have some where the top legs stand proud... it enabled us to easily solder the additional OPA PS bypasses we found benefical...
Quote: "I finally Found the alternative to my Aiyima A04 (Tilear 2.1 with best caps)"
Hi Daniboun,
Err, is it just me or did you forget to post which new one you talked about?
Link / name / price perhaps 🙂
Went to the ASR link you provided... more people posting about why you can't (or shouldn't) hear any differences because "they all measure perfectly" or "you are an idiot with your biased listening process"... than actually being constructive or having any added value. Sorry, I didn't read more than 2 pages and skipped it, time is precious.
As of 3255 vs 3251, I haven't tried any of the former and again I am in not in Class D for high end systems anyway... but considering BTL mode only, is 3255 as comfortable with under 4 Ohm speaker loads than 3251?
Hi Daniboun,
Err, is it just me or did you forget to post which new one you talked about?
Link / name / price perhaps 🙂
Went to the ASR link you provided... more people posting about why you can't (or shouldn't) hear any differences because "they all measure perfectly" or "you are an idiot with your biased listening process"... than actually being constructive or having any added value. Sorry, I didn't read more than 2 pages and skipped it, time is precious.
As of 3255 vs 3251, I haven't tried any of the former and again I am in not in Class D for high end systems anyway... but considering BTL mode only, is 3255 as comfortable with under 4 Ohm speaker loads than 3251?
I concur with this. If you’re going to try a multiple bypass arrangement on top of the adapter, e.g., both an X7R & C0G, it’s way easier if the pin tops stand proud of the mounting PCB. If you’re only going to do a single by-pass, e.g., a single 0.1uF WIMA, you can still do it with the browndog adapters.
Pete
Attachments
On ASR most people swear by measurements ... but I gladly accept positive reviews) Look here for the alternative to Aiyima A04 (black PCB):
Post #3654
I am waiting for my case but will review it next week )
TPA3255 - all about DIY, Discussion, Design etc.
I'm not using an OPA adapter as I am using a proper 8dip OPA. Now I suppose I could still use one but honestly I'm not sure the added complexity and cost as well as moving the chip further from the socket is worth it. I can probably use those 10uf ceramics under the board, they're not that big. In fact, the .1uf TDKs are nearly the same size.
So when you say you don't like X7R caps in the power circuit are you saying plain electrolytics are better? I have those too so I was planning on trying it anyway. Would film be better than either? I'm thinking if I went with 10uf film for those 9 I wouldn't need to bypasses for them.
So when you say you don't like X7R caps in the power circuit are you saying plain electrolytics are better? I have those too so I was planning on trying it anyway. Would film be better than either? I'm thinking if I went with 10uf film for those 9 I wouldn't need to bypasses for them.
Nope, didn't say that.
I said X7R not great at all for me in signal path...
but OK in PS, especialy if associated with Lytics and C0G
Film and C0G are for most applications (where you want a quality cap, sometimes you also do'nt want a low ESR and ESL but that's special etc.) the best quality. Not saying affordable or small. Obviously if PPP caps could be made small and affordable the cap market would be different LOL. They are closer than the others to what a perfect cap could be in terms of modelisation.
Now there are various film caps, and if you read the WIMA sheets you would find diffeence between MKP, MKS, MKT etc. film caps.
The thing is you don't really need 10uF as a value as that's highish for this application, just a std value they picked up. I posted already on that and in the B1 Korg thread: key words are RC high pass filters once you know what you are doing. Bottom line once you find out that 1uF or so might do the same job on some locations (as the 4 chip input caps) you can indeed afford and find the place to fit OK quality film caps and given their value indeed no bypass is required.
With 10uF film caps you won't find MKPs that fit, possibly not even MKS, but whatever it might be worth experimenting with an extra C0G bypass cap. Impossible to predict the result.
We didn't bother, I still have our MKS lying around, as said bypassing the existing caps with C0G gave us enough and even taking the cap out (eg no cap = best cap as we could in our very specific case afford to do so for 2 of these caps) gave just small disapointing gains. This is IMHO not the bottleneck on this unit, probably because it is limited in absolute terms, so money is best spent elsewhere. Having said that, most OKish film or X7R caps fitted there that would fit are more likely to give a certain colour that some might like (perhaps a perception of transparency and extra treble at the cost of bass and balance?)
Once you start spending over 200E for an amp it is time to consider IMHO other projects, as posted recently... I am quite confident we squeezed in Gilles case 95% of what was achievable in absolute terms (money no object) while remaining still resonable re money spent (but for sure not time spent LOL). In fact, all the extra potential 5% we could have achieved are likely to be of the same magnitude than the volume potentiometer project / mod to come, and that cost a few $, so no brainer for us...
All IMHO
Claude
I said X7R not great at all for me in signal path...
but OK in PS, especialy if associated with Lytics and C0G
Film and C0G are for most applications (where you want a quality cap, sometimes you also do'nt want a low ESR and ESL but that's special etc.) the best quality. Not saying affordable or small. Obviously if PPP caps could be made small and affordable the cap market would be different LOL. They are closer than the others to what a perfect cap could be in terms of modelisation.
Now there are various film caps, and if you read the WIMA sheets you would find diffeence between MKP, MKS, MKT etc. film caps.
The thing is you don't really need 10uF as a value as that's highish for this application, just a std value they picked up. I posted already on that and in the B1 Korg thread: key words are RC high pass filters once you know what you are doing. Bottom line once you find out that 1uF or so might do the same job on some locations (as the 4 chip input caps) you can indeed afford and find the place to fit OK quality film caps and given their value indeed no bypass is required.
With 10uF film caps you won't find MKPs that fit, possibly not even MKS, but whatever it might be worth experimenting with an extra C0G bypass cap. Impossible to predict the result.
We didn't bother, I still have our MKS lying around, as said bypassing the existing caps with C0G gave us enough and even taking the cap out (eg no cap = best cap as we could in our very specific case afford to do so for 2 of these caps) gave just small disapointing gains. This is IMHO not the bottleneck on this unit, probably because it is limited in absolute terms, so money is best spent elsewhere. Having said that, most OKish film or X7R caps fitted there that would fit are more likely to give a certain colour that some might like (perhaps a perception of transparency and extra treble at the cost of bass and balance?)
Once you start spending over 200E for an amp it is time to consider IMHO other projects, as posted recently... I am quite confident we squeezed in Gilles case 95% of what was achievable in absolute terms (money no object) while remaining still resonable re money spent (but for sure not time spent LOL). In fact, all the extra potential 5% we could have achieved are likely to be of the same magnitude than the volume potentiometer project / mod to come, and that cost a few $, so no brainer for us...
All IMHO
Claude
Thanks Daniboun... I must be thick today: I still haven't found the make/model nor the price of this new promising amp you "advertised"... sorry!
Claude
Claude
Wow, that's a lot to take in to be honest. I'll try to spend some time learning more about everything as I can. I really appreciate the explanations though, I just don't understand a lot of it.
So, let me ask some direct questions if I can please....
For the 9 caps, am I better off doing...
a) Electrolytics (22uf) + .1uf C0G bypass
b) Small film (MKS2B051001N00JSSD) for example or (ECQ-E1106JF)
c) Even smaller capacity (1-5uf) film (ECW-FD2W225J4) or similar
d) Stick with the 10uf ceramics and bypass them with .1uf C0G
e) Other?
Also since I'm thinking of it..... Are film or ceramic better for bypass caps? I can get small .1uf film caps or C0G ceramics
So, let me ask some direct questions if I can please....
For the 9 caps, am I better off doing...
a) Electrolytics (22uf) + .1uf C0G bypass
b) Small film (MKS2B051001N00JSSD) for example or (ECQ-E1106JF)
c) Even smaller capacity (1-5uf) film (ECW-FD2W225J4) or similar
d) Stick with the 10uf ceramics and bypass them with .1uf C0G
e) Other?
Also since I'm thinking of it..... Are film or ceramic better for bypass caps? I can get small .1uf film caps or C0G ceramics
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