ctfrommn- I am not an audio engineer, or electronics wizard, so why would I deviate from the original posters modding instructions and recommendations? You admittedly have no electronics experience, but deviated from the recipe from the get-go. I followed your suggestions for 2 pair of cheap op amps and didn't care for the outcome. I will stick with Claude's suggestions going forward. Its like people who follow a recipe for cookies but change this ingredient or that and then say they don;t like the recipe. How do they know? they changed it!
Of course do what you like. While I have very little electronics experience I have a TON (30+ years) of audio experience in both home, live, and studio. I know how things affect sound. And my deviation was after trying things as stated. Im a tinkerer as a rule. Your analogy is valid though, you should always try things as per the "recipe" before deviating. I was simply offering advice based on MY findings. Audio is extremely subjective and as I dont have the same speakers, same power supply, same PS filter, etc my results will ALWAYS be different from others on here.
I appreciate your advice on the OPA seating and will refrain from replying to you anymore.
I appreciate your advice on the OPA seating and will refrain from replying to you anymore.
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Brown Dog adapters appear to come with larger than usual pins > .6mm.
Most DIL quality turned pin Sockets will only take .5mm turned pins without damage.
So be careful what you force in to the sockets as they are easily damaged.
Most DIL quality turned pin Sockets will only take .5mm turned pins without damage.
So be careful what you force in to the sockets as they are easily damaged.
According to Cimarron (and my experience) they are actually smaller than most (0.018"/0.4572mm)
I am only reporting what other people have said about the Brown Dig adapters as I have no personal experience of these boards.
I assemble my own from the separate parts so can ensure the pins are the right size for the sockets used on most amplifier boards - ie. .5mm
James
I assemble my own from the separate parts so can ensure the pins are the right size for the sockets used on most amplifier boards - ie. .5mm
James
ctfrommn... I was about to reply to your post asking for a picture to see how far IN the Brown Dogs sitted "loose"... but you just found out yourself what I suspected: yes, one need to push and once inside they are fairly low, otherwise indeed they aren't plugged in LOL.
So all OK, moving on to the fun bit now, enjoying music 🙂
So all OK, moving on to the fun bit now, enjoying music 🙂
Sailormanbigd, good then with the 10uF caps.
Don't worry if they are Elnas or else: we are talking here about PS bypass caps, not lytics in the signal path, so good quality caps leave far less sonic fingerprints in that case and the make, as long as good ESR and ESL across all frequencies (not always documented), should be fine.
In short: no worries, not mentioning this is not the only bypass cap and the 0.1uF one would take care of any potential flow re higher frequencies.
Let us know how it sounds
Claude
Don't worry if they are Elnas or else: we are talking here about PS bypass caps, not lytics in the signal path, so good quality caps leave far less sonic fingerprints in that case and the make, as long as good ESR and ESL across all frequencies (not always documented), should be fine.
In short: no worries, not mentioning this is not the only bypass cap and the 0.1uF one would take care of any potential flow re higher frequencies.
Let us know how it sounds
Claude
Yeah, Ive never had to "seat" one so deep in the socket before. Proper 8-DIP OPA's only go in halfway or so in these machined sockets.
So good news is they work as intended. I need to fully break these in and do all the proper bypasses before I come to a final conclusion but my initial feedback is basically the same as the other pair I tried. These definitely "color" the sound vs other, more neutral sounding OPA's. Top of my head I would guess were looking at a ~1-2db "bump" at both ~80-100Hz and ~7-8kHz. Whether a "V" shaped sound is something someone likes is completely a matter of personal preference, but people should be aware of the affect they have.
OPA bypasses complete, for now.
Wima 0.1
10uf X7R
22uf Lytic
I also changed out the .1uf ceramics for the Panasonic .12uf PPP's. I did every change one at a time to preview them. Moving to PPP on the main caps was a big difference. I did end up adding a 4.7uf X7R on those as well as I do think it sounds better. I also swapped the PPP for the C0G on the center of 5 caps.
So every current modification from the stock amps are as follows......
a) Swapped main caps for United Chem-Con 4500uf low ESR
b) Bypassed the main caps with 1ea .12uf Panasonic PPP and 4.7uf (took the place of the 2x2.2uf to save space) X7R
c) Bypassed the center of 5 caps with Panasonic .12uf PPP
d) Swapped all 9 DC blocking caps with 22uf Nichicon Gold
e) Brown Dog OPA1656's
f) OPA bypasses listed above (1ea .1uf WIMA, 10uf X7R, 22uf Nichicon Gold
Almost zero chance I can get any/many more of those .12uf PPP's under the board for further bypasses but I may tinker with some more changes after all of these settle a while. This is all for now.
Wima 0.1
10uf X7R
22uf Lytic
I also changed out the .1uf ceramics for the Panasonic .12uf PPP's. I did every change one at a time to preview them. Moving to PPP on the main caps was a big difference. I did end up adding a 4.7uf X7R on those as well as I do think it sounds better. I also swapped the PPP for the C0G on the center of 5 caps.
So every current modification from the stock amps are as follows......
a) Swapped main caps for United Chem-Con 4500uf low ESR
b) Bypassed the main caps with 1ea .12uf Panasonic PPP and 4.7uf (took the place of the 2x2.2uf to save space) X7R
c) Bypassed the center of 5 caps with Panasonic .12uf PPP
d) Swapped all 9 DC blocking caps with 22uf Nichicon Gold
e) Brown Dog OPA1656's
f) OPA bypasses listed above (1ea .1uf WIMA, 10uf X7R, 22uf Nichicon Gold
Almost zero chance I can get any/many more of those .12uf PPP's under the board for further bypasses but I may tinker with some more changes after all of these settle a while. This is all for now.
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What was the voltage rating & part number of this United Chem-Con 4500uf capacitor? I don't see those anywhere.
United Chemi-Con | Aluminum Electrolytic Capacitors
I do find these United Chem-Con capacitors, but there are pretty large.....
ELXG630VSN472MR50S & ELXG630VSN472MA40S
Attachments
Well done ctfrommn
Should be now a nice sounding unit, no doubt.
Could you please do me a favour? You keep coming back on OPA1656 being coloured or V shaped. What about using a wording such as "I find that..." instead of "it is..."? I believe we all got your point of view, and it is always a nice addition. But for those joining the thread, and out of respect for all other posters who beg to differ, after such a statement I feel forced into extra work, posting that you are the only one to support and report this, and that datasheets beg to differ.
Why this? Of course it is embarrassing and of course it is not at all against you, or to counter you, or to have the last say. But I guess you know that sadly internet is done in a way that recurrent "statements" can quickly make it to the top list and hence nearly become a unique truth in this sad world.
I understand you have nothing to do with all that, don't want to ruin TI's development engineer who is a regular here and all you probably want is sharing your great enthousiasm and your sole findings, which again is great. But who will remember all that when googling... or not reading the entire thread from the start?
I hope the use of different words related to your perception can help avoiding all that...
Claude
Should be now a nice sounding unit, no doubt.
Could you please do me a favour? You keep coming back on OPA1656 being coloured or V shaped. What about using a wording such as "I find that..." instead of "it is..."? I believe we all got your point of view, and it is always a nice addition. But for those joining the thread, and out of respect for all other posters who beg to differ, after such a statement I feel forced into extra work, posting that you are the only one to support and report this, and that datasheets beg to differ.
Why this? Of course it is embarrassing and of course it is not at all against you, or to counter you, or to have the last say. But I guess you know that sadly internet is done in a way that recurrent "statements" can quickly make it to the top list and hence nearly become a unique truth in this sad world.
I understand you have nothing to do with all that, don't want to ruin TI's development engineer who is a regular here and all you probably want is sharing your great enthousiasm and your sole findings, which again is great. But who will remember all that when googling... or not reading the entire thread from the start?
I hope the use of different words related to your perception can help avoiding all that...
Claude
On another note, I had a look at the pix.
Does the board find its way back into the casing smoothly? I can't see well, but the underboard PPP caps look really quite big... 2 of them are soldered to the big PS caps and if they get lose or make a short with the casing that could be the end or worst - lot of energy there.
Of course, if you intend to put tat board in another casing with lot of underboard clearence then just ignore all this
I hope this helps
Claude
Does the board find its way back into the casing smoothly? I can't see well, but the underboard PPP caps look really quite big... 2 of them are soldered to the big PS caps and if they get lose or make a short with the casing that could be the end or worst - lot of energy there.
Of course, if you intend to put tat board in another casing with lot of underboard clearence then just ignore all this
I hope this helps
Claude
While I appreciate your "gentle" approach of telling me that doing so also forces me to respond. I will refrain from doing so though out of respect for the forum.
Thank you for the knowledge you passed along but I believe I will will also move along.
Thank you for the knowledge you passed along but I believe I will will also move along.
I’m thinking you have not completely seated the b-d-opamp-adapters into the millmax adapters. It takes a good push to get them completely pushed in. The bottom of the b-d-adapter PCB should be almost flush with the top of the millmax adapter.
Cheers,
Pete
Hello! Has anyone figured out the marking of the nameless chip ? I need to replace it.
An externally hosted image should be here but it was not working when we last tested it.
Not having an Aiyima TPA3251but one of those pesky FXAUDIO FX502SPRO instead?
Well, they are slightly worse than the Aiyima but still similar enough to be able to upgrade in a similar fashion and with a very satisfying result.
All caps is the same type as described in this thread. The copper tape around the op amps is soldered to a wire and connected to ground. It improves the sound somewhat, just make sure the tape is connected to ground otherwise it will act as an antenna and not do anything good.
Input caps are the ones in the bottom of the image. They were 2,2uF ordinary things. 10 uF Elnas and bypassed by 0,1uF G0G lived the sound up. Maybe I will remove the 0,1uF if I still think the sound is to bright.
I'm going to add an external PO89ZB filter for the power supply, but otherwise it is not worth the effort and the expense to go further.
The sound is bright and a bit "in your face" but really lifts the dull lifeless sound from before.
Well, they are slightly worse than the Aiyima but still similar enough to be able to upgrade in a similar fashion and with a very satisfying result.
All caps is the same type as described in this thread. The copper tape around the op amps is soldered to a wire and connected to ground. It improves the sound somewhat, just make sure the tape is connected to ground otherwise it will act as an antenna and not do anything good.
Input caps are the ones in the bottom of the image. They were 2,2uF ordinary things. 10 uF Elnas and bypassed by 0,1uF G0G lived the sound up. Maybe I will remove the 0,1uF if I still think the sound is to bright.
I'm going to add an external PO89ZB filter for the power supply, but otherwise it is not worth the effort and the expense to go further.
The sound is bright and a bit "in your face" but really lifts the dull lifeless sound from before.
The FXAUDIO FX502SPRO is the first TPA325X to introduce Air core inductors ) it was very innovative when it was released ... so the future Allo TPA3255 will use Air core inductors as well and this improves performance.
I'm not entirely sure that being innovative was in their heads when they designed the FX502SPRO 🙂 The wire is thin enougth be add quite a bit resistance.
The Allo TPA3255 might be worth watching though.
The Allo TPA3255 might be worth watching though.