The prices for these parts was probably set when they were first introduced which was some years ago when it was probably more expensive to produce.
New processes and smaller wafers in production meant higher costs. Also these parts at the time were the premium parts. Now of course we have larger wafers, probably better yield and hence cheaper chips !
Sometimes older parts are no longer produced so prices rise as stocks go down. Who knows !!??
It looks as if the OPA1656 gives very good performance for the money and is the current generation.
James.
No, not at all, it all depends on source resistance. 1656 has a fairly high 1/f corner, but can be used with high source resistance. Opa1612 has the lowest noise and 1/f corner, but should be used with a low source resistance. Opa 1622 is in between these two. For best result in a specific application, there is an optimal opamp. The problem with opamp rolling is that you typically deviate from optimum.
For the usual application in a TPA325x board, with two sides of an opamp in inverting configuration with highish source impedance and low gain, OPA1656 would be the best choice. But not for an MC-preamp, the 1612 would be much better.
However, NE5532 would be just as good for these boards.
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Thank you Vacufile for a much better description of the use for these parts and why some are more suitable than others in certain applications. I was certainly aware that the OPA1612 was used in different applications to the OPA1622 so this explains a lot.
Just been playing with the OPA1656 and to my ear, it sounds better than the NE5532 normally installed in TPA325x boards. My source device would typically be the headphone output from a Mac Mini or an iPhone headphone adapter. I have not invested in some fancy USB DAC as yet !!
To extend on what Vacuphile already posted, these op-amps have very different technologies, one is FET entry, the other bipolar. These are main "first consideration" op-amps family, say like fish and mammals for animals. And indeed depending on application and source, and perhaps also DC control etc. you may want to use the one or the other.
It is not like you can simply roll amps randomly, sometimes you may even destroy something doing so: some amps are very sensitive, may oscillate at high frequencies without you hearing it, or need a different PS / decoupling caps). Some are even worst and require an additional pin bottom sides or have even a different pin layout = danger!
Here there is none of that and initialy your little amp had bipolars so going for 1612 shouldn't destry anything but seems to make less sense than OPA1656 (but then the sound signature is different etc.).
As of me, I have both 1656 and 1612 but never found the time to test/hear the latter in my rig simply because my recent op-amps tests where carried out as a preselection with a given application in mind (Chipo RIAA preamp) and for this application only a FET op-amps can be considered, so that rules 1612 out for me but it remains an excellent chip at least on the paper for other applications I may consider in teh future (I/V conversion in DACs etc.)
Claude
It is not like you can simply roll amps randomly, sometimes you may even destroy something doing so: some amps are very sensitive, may oscillate at high frequencies without you hearing it, or need a different PS / decoupling caps). Some are even worst and require an additional pin bottom sides or have even a different pin layout = danger!
Here there is none of that and initialy your little amp had bipolars so going for 1612 shouldn't destry anything but seems to make less sense than OPA1656 (but then the sound signature is different etc.).
As of me, I have both 1656 and 1612 but never found the time to test/hear the latter in my rig simply because my recent op-amps tests where carried out as a preselection with a given application in mind (Chipo RIAA preamp) and for this application only a FET op-amps can be considered, so that rules 1612 out for me but it remains an excellent chip at least on the paper for other applications I may consider in teh future (I/V conversion in DACs etc.)
Claude
Really interesting and I would appreciate your help to upgrade the OP amps of my AK4497 double DAC :
Just for testing, I tried the Burson Audio V5i on it : impossible to use, weird noises, does not work at all. I have a pair of OPA1656 and OPA1612 and OPA1622
Which one do you recommend for this kind of DAC ?
- Dual AK4497EQ audio Chip
- Dual Talama linear PSU
- OPA 2X MUSE 02 + 2X MUSE 03
- Amanero USB Chipset
- Bluetooth APTX 5.0 CSR8675 LL HD
- DSD256/PCM384K
-Coax fiber 192 K 24BIT.
- USB 384 K 32BIT + DSD
- 2.8 MHz, 5.6 MHz, 11.2 MHz, 22.4 MHz DSD
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New board?
#Aliexpress US $64.66 34%OFF | Lusya TPA3255 Digital Amplifier Audio Board 4 channel class D Amplifier Board 315W*4 for 4-8 ohm speaker T1402
Lusya TPA3255 Digital Amplifier Audio Board 4 channel class D Amplifier Board 315W*4 for 4 8 ohm speaker T1402|Amplifier|Consumer Electronics - AliExpress
#Aliexpress US $64.66 34%OFF | Lusya TPA3255 Digital Amplifier Audio Board 4 channel class D Amplifier Board 315W*4 for 4-8 ohm speaker T1402
Lusya TPA3255 Digital Amplifier Audio Board 4 channel class D Amplifier Board 315W*4 for 4 8 ohm speaker T1402|Amplifier|Consumer Electronics - AliExpress
I saw it yesterday as well, also here :
I was perplex reading the Title... but I also found it here, this is a TPA3255 with 4 channels.
Lusya TPA3255 carte Audio amplificateur numerique 4 canaux classe D carte amplificateur 315W * 4 pour haut parleur 4 8 ohms T1402|Amplificateur|Electronique - AliExpress
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Danny,
I will of course let Vacuphile reply, but as a small thread hi-jack...
To find out what is feasible in terms of op-amp rolling you need the schematic and to really understand it - it is not a matter of device spec or chips used.
You have to find out what the op-amp is doing inside the unit, what it stands for, why it has been implemented. Better isn't necessarly better, some op-amps are very well suited to some given applications and also their specs may have been taken into account to get the most out of them... going for a supposedly better one is often not a good idea, you are just making things worst forcing an op-amp into a position it is not designed for, or in a circuit that has been optimised for another op-amp, taking some corrections and consideration into account that may contradict with the op-amp you wish to implement. Further, some designer are correctling the sound balance in output filters or with components to get the sonic signature they want... when using their op-amp.
It is like cooking, you can't just throw all the best ingredients in the pan randomly and hope thus to get the best meal...
Mic to Vacuphile, sorry for the interference!
Claude
I will of course let Vacuphile reply, but as a small thread hi-jack...
To find out what is feasible in terms of op-amp rolling you need the schematic and to really understand it - it is not a matter of device spec or chips used.
You have to find out what the op-amp is doing inside the unit, what it stands for, why it has been implemented. Better isn't necessarly better, some op-amps are very well suited to some given applications and also their specs may have been taken into account to get the most out of them... going for a supposedly better one is often not a good idea, you are just making things worst forcing an op-amp into a position it is not designed for, or in a circuit that has been optimised for another op-amp, taking some corrections and consideration into account that may contradict with the op-amp you wish to implement. Further, some designer are correctling the sound balance in output filters or with components to get the sonic signature they want... when using their op-amp.
It is like cooking, you can't just throw all the best ingredients in the pan randomly and hope thus to get the best meal...
Mic to Vacuphile, sorry for the interference!
Claude
Danny,
I will of course let Vacuphile reply, but as a small thread hi-jack...
To find out what is feasible in terms of op-amp rolling you need the schematic and to really understand it - it is not a matter of device spec or chips used.
You have to find out what the op-amp is doing inside the unit, what it stands for, why it has been implemented. Better isn't necessarly better, some op-amps are very well suited to some given applications and also their specs may have been taken into account to get the most out of them... going for a supposedly better one is often not a good idea, you are just making things worst forcing an op-amp into a position it is not designed for, or in a circuit that has been optimised for another op-amp, taking some corrections and consideration into account that may contradict with the op-amp you wish to implement. Further, some designer are correctling the sound balance in output filters or with components to get the sonic signature they want... when using their op-amp.
It is like cooking, you can't just throw all the best ingredients in the pan randomly and hope thus to get the best meal...
Mic to Vacuphile, sorry for the interference!
Claude
Claude, many thanks ) I really appreciate the US efficiency...
This must be one of the reasons why you are N°1 in the World !
I will cook my OP amps with delicacy and especially according to my tastes lol... I am far from having your theoretical knowledge
It is never too late to learn: right?
Looks like a copy of the 3E audio dual TPA3251 board:
TPA3251 4x100W 4Ch Class D Audio Amplifier | eBay
Lusya:
3E audio:
//edit: product title now reads: Lusya LM1876 Digitale Versterker Audio Board dual channel 60W Versterker Board voor 4-8 ohm luidspreker
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Looks like a copy of the 3E audio dual TPA3251 board:
TPA3251 4x100W 4Ch Class D Audio Amplifier | eBay
Lusya:
3E audio:
//edit: product title now reads: Lusya LM1876 Digitale Versterker Audio Board dual channel 60W Versterker Board voor 4-8 ohm luidspreker
Poor or good copy ) We will probably see soon )
Danny, I don't know much and you are willing to learn a lot... so you will catch up fast
BTW, I am based in your country but not near Lyon, and I am French... but I wasn't born in F and indeed spent quite a few years in D, UK, US etc. and have in fact worked on all continents except the Antartic.
Explains though perhaps why I am sensitive to the the difference between "efficient" and "efficace" - that gives me always lot of trouble down here ;-)
Enjoy music
Claude
BTW, I am based in your country but not near Lyon, and I am French... but I wasn't born in F and indeed spent quite a few years in D, UK, US etc. and have in fact worked on all continents except the Antartic.
Explains though perhaps why I am sensitive to the the difference between "efficient" and "efficace" - that gives me always lot of trouble down here ;-)
Enjoy music
Claude
Danny, I don't know much and you are willing to learn a lot... so you will catch up fast
BTW, I am based in your country but not near Lyon, and I am French... but I wasn't born in F and indeed spent quite a few years in D, UK, US etc. and have in fact worked on all continents except the Antartic.
Explains though perhaps why I am sensitive to the the difference between "efficient" and "efficace" - that gives me always lot of trouble down here ;-)
Enjoy music
Claude
Nice to learn it ) I guess you are polyglot ?
I was born in Brasil to be honest but I have been living in France for many years. My mum is Italian and my father Polish.I have traveled a lot lol
Let's say rather that the Americans are performing lol let's be smart )
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Really interesting and I would appreciate your help to upgrade the OP amps of my AK4497 double DAC :
Just for testing, I tried the Burson Audio V5i on it : impossible to use, weird noises, does not work at all. I have a pair of OPA1656 and OPA1612 and OPA1622
Which one do you recommend for this kind of DAC ?
- Dual AK4497EQ audio Chip
- Dual Talama linear PSU
- OPA 2X MUSE 02 + 2X MUSE 03
- Amanero USB Chipset
- Bluetooth APTX 5.0 CSR8675 LL HD
- DSD256/PCM384K
-Coax fiber 192 K 24BIT.
- USB 384 K 32BIT + DSD
- 2.8 MHz, 5.6 MHz, 11.2 MHz, 22.4 MHz DSD
Hi Daniboon,
Let me also help you figure out stuff like this for yourself. I don't know the details from your board btw.
When you look at the specsheet for the AK4497, you will find some circuit examples (from page 96).
https://www.akm.com/content/dam/doc.../audio-dac/ak4497eq/ak4497eq-en-datasheet.pdf
As you can see, they use opa1611 or 1612. You can also see from the values on the resistors, that the have low values. Therefore, you want an opamp with lowest possible voltage noise and lowest possible 1/f noise corner. You can gain all these values from the spec sheets of these opamps. If you do, you will find that opa1622 and 1656 are not optimum for this application. In view of the high quality of the AK4497, it deserves the best possible opamps for I-V conversion.
Muse is written with the M of marketing for a reason.
Yes, that's an interesting point, and it's consistent with my results when bypassing the 3e-audio TPA3251 input opamps, as I reported here -
https://www.diyaudio.com/forums/cla...iy-discussion-design-etc-177.html#post6087528
I found that direct input to the TPA3251 is wonderfully detailed and clean. I understand that some might consider this sound "sterile" but I would use a less severe term - I would call it "dry".
And as you say, it may depend on your source. My DAC has a transformer output stage, which several other owners have found to be unsuitable for direct connection to a power amp - they say it needs a buffer or linestage before power amp.
Of course this type of DAC output stage is uncommon - most DAC's have opamps as their output stage. And for such DAC's which provide balanced outputs, this seems to me a good candidate for direct connection to a TPA3251. Sure, a TPA3251 may sound good with an OPA1656 at the input, but maybe it sounds better with just the DAC's opamps in the signal chain?
daniboun, would you be interested to test your dual-AK4497 DAC direct to your AIYIMA TPA3251? The results could be very interesting.
As ClaudeG explained, once the opamps are removed, you can feed balanced signals into the exposed DIP8 sockets. You will need a cable which is male XLR to DIP8 plug.
20 years ago I was part of the hype behind the ART DI/O modifications.
The most advanced DAC modders were either using transformers at the output stage... or my AD825 set up - I believe none but me dared the Class A mod on that one.
So transformers driving directly a power amp is nothing new, but we had back then a pot in the middle as no digital volume and needed more complicated input stages. Whatever, tranny vs AD825 units, some reported a loss of drive, others were happy with the relaxed sound, so I would say your safest bet is to try by yourself as back then there were no conclusive answer, more taste and colours and different needs / hifi systems.
You may want to make sure though that your transformers can drive the power chip without high frequency roll off. Higher values may be possible, but my guess would be an output impedance of 2k should still be on the safe side. If higher, you may want to analyse in details the circuit. Of course 20y ago there were also those wanting some roll off because they got rid of the analog output filter, LOL!
Good luck
Claude
The most advanced DAC modders were either using transformers at the output stage... or my AD825 set up - I believe none but me dared the Class A mod on that one.
So transformers driving directly a power amp is nothing new, but we had back then a pot in the middle as no digital volume and needed more complicated input stages. Whatever, tranny vs AD825 units, some reported a loss of drive, others were happy with the relaxed sound, so I would say your safest bet is to try by yourself as back then there were no conclusive answer, more taste and colours and different needs / hifi systems.
You may want to make sure though that your transformers can drive the power chip without high frequency roll off. Higher values may be possible, but my guess would be an output impedance of 2k should still be on the safe side. If higher, you may want to analyse in details the circuit. Of course 20y ago there were also those wanting some roll off because they got rid of the analog output filter, LOL!
Good luck
Claude
Hi, I would be very happy to do it but can you show me that cable ?
My DAC has 4 OP amps (Double + Simple). I guess the Double OP Amps are used for the RCA output and the Simple ones for the XLR. looks like this :
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