It was some plugs left from my speaker DIY speaker project, from the brand stäubli.
I would recommend these for the tpa3255, good for 24 A:
https://www.amazon.se/Bananpluggar-Bananuttag-Förlängd-Stolpepanel-Bananjackkontakt/dp/B09YYKXWB5/ref=sr_1_31?crid=3PF4RVZLV129L&dib=eyJ2IjoiMSJ9.otvVQM0z5vdN3k13vUhSc-1hQMdWmlTDZJS1mvtyn2SOGpTXgvk1R2qJR_fXiT14n2IV90Bbqoa0sTRGqDmrCqY-RHqLasRajxzZbnOW9NEIdZ5vCf59OUjVa_zBfCpNQVGP8E3sP9OA6SOaC0IfqY3HuH8n9C8aEAfq10vwEc2q9wJI16D6L0wmeHCQzgXKDlTqbhplwr03iUh-J_eYUJ4LE8vLfJRmJXjTMvnG2H9eMaU7RXIuNDMu_BVe-9ohyXCBYzgXa_BoqIwy-mBn-KMn0Kay9RnaPetmIOxiTStswbJpDqhiPHNyCSJfGdGzJIhqtCoXIL6voE63dNkr2ZbxWc2Dyk_D1CbKXMFJgLyL24mQ9h7QQAIuO_5zsRZ1piApukPoLH4_KyBMuNB_AW1pdgzAN37iBxURVGgRMyKT239Wz3_HKZ_xmg55Csy3.yfFlcfadp3PlW2cHA31obNHcbIzfVdOpkLbwzaBQDjY&dib_tag=se&keywords=banankontakt+hona&qid=1734534459&sprefix=banankontakt+hona+,aps,108&sr=8-31
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The sound is still surprisingly good after 3 weeks of use , my hypex ncore 125 collecting dust at the moment.
I use this 36V 6A power brick :
https://www.amazon.se/Brensty-Strömadapter-förstärkare-TDA7498E-ljudförstärkare/dp/B0CWP2T643/ref=sr_1_19?crid=HXT5KM1SPYEO&dib=eyJ2IjoiMSJ9.v6YHvKJHON52o-K0uKr-2iEzyz0d4GQt6qfYXENomkoRNKrCrn-lF6H7zy-VZxY3fsD_iyb_J03WTGeAUlAbQudraNSdSFiVi1LNvxv8fFEM_cmoLwDuAdDieawDx97CpEdjqyXkCDemz0VW0vgM_rzwjh-6YOFSwE9bI2hbgFxfcSJCzP1no_Z_hvumPR7Mhij7c_Vjv0BaDuSTJ5uR3KJxomm33fAguOIf16kNiSxbTCbyTG1_VnO8sl-LgNsk24zhNZRJai5fjuUfwbulqiFksvxZ0c2oHAf1brVhQmscZlV5zEH225DA_6vcp9r0wbiFGilDGLrnru9sd95BgLB4Ku3Zvpjn-rqyMVZpNEAtI2j3zem7jKI_tuKRHBohKQY52RNOMUvrAh2PTnhByS7ptmeu4_lW7GwNid8PQAqFzjaW4U8Hv-YIbjIzZAL9.BquB8NF-r8FMMJXTIWcZzTazgODRt-7kITathK3x9K8&dib_tag=se&keywords=Tpa3255+power+brick&qid=1734535620&sprefix=tpa3255+power+brick,aps,95&sr=8-19
Im sure the sound would be even better with a more expensive power supply, or maybe one more of these 3255 boards , in dual mono ?🙂
Doing that, the price would be higher reaching pffb solutions like fosi v3 mono. So, not sensible.
By the way - Im not 100% convinced that a pffb 3255 always sounds better than a good 3255 without pffb and with good op amps.
Most pffb 3255 on the market seems to do pffb with an extra ne5532 - not my favorite.
Maybe Im wrong on this.
I use this 36V 6A power brick :
https://www.amazon.se/Brensty-Strömadapter-förstärkare-TDA7498E-ljudförstärkare/dp/B0CWP2T643/ref=sr_1_19?crid=HXT5KM1SPYEO&dib=eyJ2IjoiMSJ9.v6YHvKJHON52o-K0uKr-2iEzyz0d4GQt6qfYXENomkoRNKrCrn-lF6H7zy-VZxY3fsD_iyb_J03WTGeAUlAbQudraNSdSFiVi1LNvxv8fFEM_cmoLwDuAdDieawDx97CpEdjqyXkCDemz0VW0vgM_rzwjh-6YOFSwE9bI2hbgFxfcSJCzP1no_Z_hvumPR7Mhij7c_Vjv0BaDuSTJ5uR3KJxomm33fAguOIf16kNiSxbTCbyTG1_VnO8sl-LgNsk24zhNZRJai5fjuUfwbulqiFksvxZ0c2oHAf1brVhQmscZlV5zEH225DA_6vcp9r0wbiFGilDGLrnru9sd95BgLB4Ku3Zvpjn-rqyMVZpNEAtI2j3zem7jKI_tuKRHBohKQY52RNOMUvrAh2PTnhByS7ptmeu4_lW7GwNid8PQAqFzjaW4U8Hv-YIbjIzZAL9.BquB8NF-r8FMMJXTIWcZzTazgODRt-7kITathK3x9K8&dib_tag=se&keywords=Tpa3255+power+brick&qid=1734535620&sprefix=tpa3255+power+brick,aps,95&sr=8-19
Im sure the sound would be even better with a more expensive power supply, or maybe one more of these 3255 boards , in dual mono ?🙂
Doing that, the price would be higher reaching pffb solutions like fosi v3 mono. So, not sensible.
By the way - Im not 100% convinced that a pffb 3255 always sounds better than a good 3255 without pffb and with good op amps.
Most pffb 3255 on the market seems to do pffb with an extra ne5532 - not my favorite.
Maybe Im wrong on this.
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Fosi v3 mono is so damn good.....
I used Fosi M03 before for my center channel duty and compared with Fosi v3 mono its like a big upgrade, every dialogue is more clear now
They have a same opamp (NE5532), same power Supply (Meanwell) but with different schematic everything is different...
You can rolling the op-amp, change the capacitor or inductor to a better type, but it never beats an amp with a better schematic (or maybe my FOSI M03 is so bad)
I used Fosi M03 before for my center channel duty and compared with Fosi v3 mono its like a big upgrade, every dialogue is more clear now
They have a same opamp (NE5532), same power Supply (Meanwell) but with different schematic everything is different...
You can rolling the op-amp, change the capacitor or inductor to a better type, but it never beats an amp with a better schematic (or maybe my FOSI M03 is so bad)
Are you driving your fosi v3 mono with 36 V ? It seems to get low distortion with the tpa3255 . The sweet spot according to measurements with lowest distortion at 8 ohm load is about 35V , rather far away from the usual 48V.
Those Stäubli 4 mm safety banana connectors sure look OK but these should of course not be soldered. More or less visually equal versions by Hirschmann are also very good. At SKS Hirschmann they are called SEB2600 and even usable up to 32A (63A older series also exits).
Link to the solderable + ring type AMP connector gold plated version:
https://www.sks-kontakt.de/de/test-measurement/produkte/produkt?nr=9723541
Link to the non solderable 6.3 mm Faston gold plated version:
https://www.sks-kontakt.de/de/test-measurement/produkte/produkt?nr=9723621
The solderable versions are longer because otherwise the plastic melts.
Link to the solderable + ring type AMP connector gold plated version:
https://www.sks-kontakt.de/de/test-measurement/produkte/produkt?nr=9723541
Link to the non solderable 6.3 mm Faston gold plated version:
https://www.sks-kontakt.de/de/test-measurement/produkte/produkt?nr=9723621
The solderable versions are longer because otherwise the plastic melts.
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Thanks for pointing this out, Jean-Paul.
I destroyed one of the stäublis by having to much heat to long, but I had 20 of them so I could afford to switch. I just did it the simple way, my soldering iron was already hot .🙂
If soldering, probably best to use solder with low melting temperature, or use different plugs made for soldering.
I destroyed one of the stäublis by having to much heat to long, but I had 20 of them so I could afford to switch. I just did it the simple way, my soldering iron was already hot .🙂
If soldering, probably best to use solder with low melting temperature, or use different plugs made for soldering.
It can be simple. Solder stuff that is meant to be soldered and crimp stuff that is meant to be crimped.
Why many DIYers specifically buy switches, connectors, IEC inlets etc. meant for either 4.8 or 6.3 mm Faston connectors and solder these and call this the simple way is unknown 😀
BTW for high current crimping is technically better. Mr. Lorentz is to blame. https://en.wikipedia.org/wiki/Hendrik_Lorentz
Why many DIYers specifically buy switches, connectors, IEC inlets etc. meant for either 4.8 or 6.3 mm Faston connectors and solder these and call this the simple way is unknown 😀
BTW for high current crimping is technically better. Mr. Lorentz is to blame. https://en.wikipedia.org/wiki/Hendrik_Lorentz
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Yes.... the fosi v3 mono got many problem for the heat issue in internet. I got mine for less than $40 include shipment because the previous owner got this problem. Turn out it run fine in 36v and when i open the enclosure there is no thermal paste between enclosure and thermal plate. I set the amp gain to +31 because use REW for room calibration so +25 gain is to low
Some things has changed during the last week.
I have done some opamp rolling and the best chip for this amplifier is clearly OPA1642, a fet input opamp with a CMRR of 126.
My WiiM Ultras internal dac, after the last 4 firmware upgrades obviously sounds better than before, or this might be a case of system matching ?
The inbuilt dac in the Ultra now sounds on pair with the Rega dac , if using opa1642 as opamps in my amplifier. The WiiM Ultra uses 4 opa1612 at the dac output and I might prefer some fet-colorations from the opa1642 ?
Using the WiiM with the Rega dac together with opa1642, it sounds a little to analog and nice, here I might ( maybe ) prefer the opa1612 in the amplifier.
I also noticed that the sound from the opa1642 changed a bit for the better after about 3 hours. More effortless sound and cleaner.
I have also implemented some voltage dividers to lower the input gain 10 dB , using Vishay dale resistors.
This was a clear improvement from my Monacor inline RCA attenuator in soundquality , despite using same values for the vishays, resistor quality seems to matter. More details in the music.
I also used two 4,7 Wima:s at input coupling .
I have done some opamp rolling and the best chip for this amplifier is clearly OPA1642, a fet input opamp with a CMRR of 126.
My WiiM Ultras internal dac, after the last 4 firmware upgrades obviously sounds better than before, or this might be a case of system matching ?
The inbuilt dac in the Ultra now sounds on pair with the Rega dac , if using opa1642 as opamps in my amplifier. The WiiM Ultra uses 4 opa1612 at the dac output and I might prefer some fet-colorations from the opa1642 ?
Using the WiiM with the Rega dac together with opa1642, it sounds a little to analog and nice, here I might ( maybe ) prefer the opa1612 in the amplifier.
I also noticed that the sound from the opa1642 changed a bit for the better after about 3 hours. More effortless sound and cleaner.
I have also implemented some voltage dividers to lower the input gain 10 dB , using Vishay dale resistors.
This was a clear improvement from my Monacor inline RCA attenuator in soundquality , despite using same values for the vishays, resistor quality seems to matter. More details in the music.
I also used two 4,7 Wima:s at input coupling .
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Nice work!
You have a simple implementation that only requires basic hole drilling - good for DIY. I like the simplicity.
In general, the aluminum chassis are better from heat conduction. Real multi-way binding posts allow more connection options for speaker cables and look better. Also, they have thicker copper posts which reduce output impedance. You are losing a lot of bass authority going through those thin banana plug jacks which were designed for low current applications. If you were to measured your amp damping factor at the amp and after the connectors, you will notice a significant difference. Its main impact is bass authority. The change of film caps at output is critical as X7R ceramic caps are not suitable for audio output filters due to their distortion and inherent piezoelectric effect.
The yellow Elna caps are probably fake. Never seen yellow ones like that. Real Elna audio caps are brown and finer print. These are not expensive at $0.35 for 10uF 35v. But they sound and measure about as good as some of the best much larger film caps.
The real ones look like this:
I would suggest an LED power indicator to know amp is on and powered. It is also good to have a power switch. You would need a high current one or use a 10A relay powered by the 36v (maybe use LM7824 to drop voltage for 24v coil). A small pushbutton switch can power relay.
Depending on how much power you like to run at, you may or may not need vent holes. On my amp, the chip is thermal bonded to the 5mm thick aluminum baseplate and the case serves as the external radiator so no vents needed.
Summary of suggestions:
1. Use proper high current speaker or amp 5 way binding posts for speaker out. Use 16ga x 2 or 14ga multi strand silicone wire to connect amp to binding posts. All this improves bass authority.
2. Use real Elna Silmic II 10uF 35v caps on the input DC isolation caps. (Edit - just saw your Wima film caps on input. That’s fine).
3. Add LED indicator. This can be integral to switch.
4. Add low voltage activated relay to power amp on and off from front panel switch.
5. Use real RCA connectors for input and use shielded RG174 cable from RCA to amp. (Edit: your RCA’s are good brand)
6. Electrically ground the chassis to reduce EMI emission.
7. Add vent holes if needed.
You have a simple implementation that only requires basic hole drilling - good for DIY. I like the simplicity.
In general, the aluminum chassis are better from heat conduction. Real multi-way binding posts allow more connection options for speaker cables and look better. Also, they have thicker copper posts which reduce output impedance. You are losing a lot of bass authority going through those thin banana plug jacks which were designed for low current applications. If you were to measured your amp damping factor at the amp and after the connectors, you will notice a significant difference. Its main impact is bass authority. The change of film caps at output is critical as X7R ceramic caps are not suitable for audio output filters due to their distortion and inherent piezoelectric effect.
The yellow Elna caps are probably fake. Never seen yellow ones like that. Real Elna audio caps are brown and finer print. These are not expensive at $0.35 for 10uF 35v. But they sound and measure about as good as some of the best much larger film caps.
The real ones look like this:
I would suggest an LED power indicator to know amp is on and powered. It is also good to have a power switch. You would need a high current one or use a 10A relay powered by the 36v (maybe use LM7824 to drop voltage for 24v coil). A small pushbutton switch can power relay.
Depending on how much power you like to run at, you may or may not need vent holes. On my amp, the chip is thermal bonded to the 5mm thick aluminum baseplate and the case serves as the external radiator so no vents needed.
Summary of suggestions:
1. Use proper high current speaker or amp 5 way binding posts for speaker out. Use 16ga x 2 or 14ga multi strand silicone wire to connect amp to binding posts. All this improves bass authority.
2. Use real Elna Silmic II 10uF 35v caps on the input DC isolation caps. (Edit - just saw your Wima film caps on input. That’s fine).
3. Add LED indicator. This can be integral to switch.
4. Add low voltage activated relay to power amp on and off from front panel switch.
5. Use real RCA connectors for input and use shielded RG174 cable from RCA to amp. (Edit: your RCA’s are good brand)
6. Electrically ground the chassis to reduce EMI emission.
7. Add vent holes if needed.
Known behavior from the OPA1642. It is a very good pretty universal opamp. One would choose another type purely judging from the datasheet numbers but in reality it is better than expected. I don't think it is colored at all really.
Replacing the last 2 output opamps (singles I think so OPA1641) IN the Ultra will likely make the Rega DAC redundant.
Replacing the last 2 output opamps (singles I think so OPA1641) IN the Ultra will likely make the Rega DAC redundant.
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OPA1642 is one fine sounding opamp. I use it in almost all projects using an opamp. I will use OPA1656 when I need more output current drive.
Yes, many report that Eversolo dmp6 internal dac sounds slightly better than the Ultra:s despite having the same dac chip and one of the reason may well be opa1642 used in dmp6 ?
Having opa1612 everywhere like in Ultra seems to worsen the flow in the music and sounding more stacatto, but this is my opinion as an amateur and I have no measurements to back this up.
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First device in years that I haven’t opened. I just use it for what it is designed for. It seems an example of fine engineering.
Only from useful features alone it has the upper hand.
Only complaint I have is the slow transfer of files via LAN to the SSD in MacOS. But at least it can have an SSD.
Only from useful features alone it has the upper hand.
Only complaint I have is the slow transfer of files via LAN to the SSD in MacOS. But at least it can have an SSD.
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