Hi
I acquired an Accuphase T-100 and plan to refurbish it. Before the multiplex chip, there's a LM749 driving it. As it is a TO99 op amp, the op amp choice is rather small. I want to keep a to99 op amp in this place. I hate the OPA627 which I find too laidback and lacking life, The LME49710 is better but is the opposite of the OPA627 ( too cold sounding) There's the AD744 wich I never tried. Is there any other interesting choices ? The T-100 has some emphasis in the mid high (lean mids) so a warm sounding op amp should be perhaps good.
Thanks
I acquired an Accuphase T-100 and plan to refurbish it. Before the multiplex chip, there's a LM749 driving it. As it is a TO99 op amp, the op amp choice is rather small. I want to keep a to99 op amp in this place. I hate the OPA627 which I find too laidback and lacking life, The LME49710 is better but is the opposite of the OPA627 ( too cold sounding) There's the AD744 wich I never tried. Is there any other interesting choices ? The T-100 has some emphasis in the mid high (lean mids) so a warm sounding op amp should be perhaps good.
Thanks
Any chance you have a link to the surrounding circuit?
It's a bjt-input opamp. Most anything nowadays will work. Likewise, there are adapters for TO99 to various other shapes and sizes. 🙂
Given the age of the circuit and the opamp, make sure you pay attention to some local decoupling of the power supply pins on your replacement. Or you're asking for oscillations.
It's a bjt-input opamp. Most anything nowadays will work. Likewise, there are adapters for TO99 to various other shapes and sizes. 🙂
Given the age of the circuit and the opamp, make sure you pay attention to some local decoupling of the power supply pins on your replacement. Or you're asking for oscillations.
Your question has no answer because you use all subjective psychological descriptions which have no correlation in the real world, definitely nothing that can be compared or measured.
Those hollow meaning words mean different things to different people (since they are subjective), so even if somebody answers, what he thinks those words mean will not match what your words do.
Those hollow words like you wrote are understood by many peoples in the audio circle. Please don't loose your time and mine with such writings because it doesn't add any information or doesn't help anybody here.
I don't think this is a 741, the multiplex decoder driver has frequency compensation and is amplifying the raw stereo encoded signal
The T-100 service manual shows TA7045m, not a conventional opamp.
Apparently similar to this http://www.weisd.com/store2/NTE724.pdf
Apparently similar to this http://www.weisd.com/store2/NTE724.pdf
Hi David
In my service manual, this is a LM741 and it is clearly written on the part in the MPX board. I suppose there was many versions of this tuner.
In my service manual, this is a LM741 and it is clearly written on the part in the MPX board. I suppose there was many versions of this tuner.
I just looked at the TA7045M,
I really want to find one to try it at the place of the poor LM741.
Can I find the shematic you have on the web ? I would like to see if they made other changes other than the TA7045M in this tuner.
I really want to find one to try it at the place of the poor LM741.
Can I find the shematic you have on the web ? I would like to see if they made other changes other than the TA7045M in this tuner.
The LM741 would be way out of its depth handling a ~70kHz bandwidth encoded stereo signal, due to the poor slew rate, many cheap parts like the LM301 would have been more suitable back in the day.
I was reading this http://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Accuphase-T-100-Service-Manual.pdf
I was reading this http://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Accuphase-T-100-Service-Manual.pdf
If you really want to improve the sound of the Accuphase T-100, look for someone who can align it properly. Assuming you got it already aligned, changing IC1 TA7502M opamp that feeds the MC/LM1310 WILL definitely alter the stereo separation. This will make any subjective comparison void.
Part swapping on an FM tuner is generally not a good idea especially on sections between the front end and the MPX decoder. Some FM tuners even have their stereo separation adjustment right on the final line output buffer section. So simply changing a capacitor or resistor with a better spec part can inadvertently mess up stereo imaging.
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