Hi everybody! So I have a Revox B 226-s
I was recommended by a user to change these opamps. It was supposed to be 2 different Opamps NE5532 and LM833.
and the replacement was OPA1642 and OPA1656. But when I opened the machine.. (Wich I should done inte first place I know) there different Opamps. 4 RC5532N
I have tried to contact this user although he doesn’t answer. Is there someone here with Experience in this? Or do I miss understand him? I’m attacking a picture on the Inside of the Revox.
Thanks.
I was recommended by a user to change these opamps. It was supposed to be 2 different Opamps NE5532 and LM833.
and the replacement was OPA1642 and OPA1656. But when I opened the machine.. (Wich I should done inte first place I know) there different Opamps. 4 RC5532N
I have tried to contact this user although he doesn’t answer. Is there someone here with Experience in this? Or do I miss understand him? I’m attacking a picture on the Inside of the Revox.
Thanks.
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The RC5532 and NE5532 are just different brands. The LM833 is similar to the 5532. They are both highly regarded bjt type opamps.
You need to to study the circuit the circuit see what may and may not be suitable replacements. While the OPA devices will likely be fine (and the OPA1642 is the better device compared to the OPA1656) you should still be aware that sometimes things don't always go as planned. Always ask yourself why you want to change them and what aspects you want to improve on.
https://www.diyaudio.com/community/...-checked-to-see-its-stable-havent-you.191389/
You need to to study the circuit the circuit see what may and may not be suitable replacements. While the OPA devices will likely be fine (and the OPA1642 is the better device compared to the OPA1656) you should still be aware that sometimes things don't always go as planned. Always ask yourself why you want to change them and what aspects you want to improve on.
https://www.diyaudio.com/community/...-checked-to-see-its-stable-havent-you.191389/
Ah ha, well that is the big question. Only you can decide that one through extended listening. Fwiw opamps can impart their own quality to the sound but in my experience it tends to be application specific (opamps used at the output of D/A convertors for example). For standard gain applications the 5532 and 833 are hard to beat, but don't let that stop you trying.
One thing to check is the actual supply voltage they are running on because the 5532 is rated to 44 volts in total (-/+22v). Typically they will be used at less than that and -/+18 is more common but worth checking before you swap any. Most opamps are rated for 36 volts (-/+18v) as a maximum.
One thing to check is the actual supply voltage they are running on because the 5532 is rated to 44 volts in total (-/+22v). Typically they will be used at less than that and -/+18 is more common but worth checking before you swap any. Most opamps are rated for 36 volts (-/+18v) as a maximum.
Hmm.. this seems far more complicated than it’s worth…. The engineer i ordered the Opamps from said (you won’t notice any difference)
I wonder if this is the same user that didn’t reply to my questions regarding his forum advice on parts sound? If this person is online everyday posting but fails to reply after weeks or months, maybe their advice isn’t worth your trust.
- Be aware the OPA1642 uses a j-fet input, while all the others listed have a bipolar input.
It is an unanswerable question.
If you found you thought there was a difference it is only you can then say whether it is better or not, or more correctly whether you prefer one over the other.
Ok that’s it. I won’t touch it. Maybe these RC5532N are better than the ones he mentioned anyway. Maybe this Revox is a later model where they corrected somethings in the output stage. Although I’m probably going to modify the SAA7220 with a power regulator
If the replacements are not stable with the existing layout and decoupling arrangement of the circuit, then there will be audible difference as an opamp oscillating at radio frequencies has high noise and distortion in the audio band.
And the worst case is your new devices work on the bench OK, but start misbehaving in the field due to being only marginally stable.
Case in point: I was taking distortion measurements of various different opamps on a breadbord, and several measured as expected but then I tried some LM4562's I had knocking around. They fell 50dB short of datasheet distortion performance.... I wondered if they were fakes, but eventually some experimentation revealed they required more decoupling than just 100nF between V+ and V- rails (which the previous opamps were stable with). Fix the decoupling and they behaved properly.
I am sure many instances of opamp-rolling preferences between different opamps boil down to some oscillating and some not...
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I would not try op amp rolling if I did not have access to an oscilloscope to verify that that I don't end up with a tweeter killing op amp substitution.
Some opamp instabilities are way up in the VHF region, not going to blow tweeters as RF wouldn't get through a power amp, but can increase distortion... Its alleged that an inadequately decoupled 5532 can show no signs on a normal fast 'scope, but clearly show increased distortion on an audio analyzer... Adding 100nF from V+ to V- can fix this, so clearly something is happening. Think this was a Doug Self article I heard this.