Behringer MX8000 opamp upgrade

[Gulistan]

I'm the owner of an Behringer MX8000 since 2 months (a very great deal on ebay...).
PCB is populated by NJM4580 (SIL package !). I want to upgrade them with NJM5532 or NJM2114. All console ? only mic preamps (2SB737, 2N4401, NJM4580).
Any idea ?

I'll also change transformer and electro capacitors in PSU.

 

[MikoKensington]

If the PSU is anything like the 9000 you probably won't want to change the power tranformer. The caps, for sure. You never know when there going to explode. POP!

My 2 Cents. When all is said and done you probably won't hear that much of an improvement from all your hard work. If you're using it as a front end. I'd just use it till you can get something better. If you're using it to mix and monitor, I'd concentrate on the summing networks.

 

[Gulistan]

My 2 Cents. When all is said and done you probably won't hear that much of an improvement from all your hard work. If you're using it as a front end. I'd just use it till you can get something better. If you're using it to mix and monitor, I'd concentrate on the summing networks.

Yes, I know this... but I bought it ~300? and it's like new.
For sure, i'll buy another console in the nexts months (Makie Onyx ?).

If the PSU is anything like the 9000 you probably won't want to change the power tranformer. The caps, for sure. You never know when there going to explode. POP!

The transformer make noise (vvvrrrrr....!!!) and caps looks cheap.

 

[MikoKensington]

Are you sure it's not fan noise?

 

[Gulistan]

Are you sure it's not fan noise?

It's the transformer... the fan is quiet...

 

[Rossi]

[quote author="Gulistan"]I'm the owner of an Behringer MX8000 since 2 months (a very great deal on ebay...).
PCB is populated by NJM4580 (SIL package !). I want to upgrade them with NJM5532 or NJM2114. All console ? only mic preamps (2SB737, 2N4401, NJM4580).
Any idea ?
[/quote]

Interesting. I had similar inclinations recently. I'd also like to try the NJM2114 as a substitute for the NJM4580, but only on the preamp boards. My MX8000 is a fairly early one (grey model, sold without the meter extension). It uses the same transistors for the preamps as yours. I assume they later switched to different transistors when the 2SB737 was discontinued. But I don't know for sure. Do you have any idea when your MX8000 was built?

On the other hand I hardly use my MX8000 anymore and I'm not sure the modding would be worth the effort. May actually be counterproductive in case I want to sell it.

 

[Svart]

are the 4580's pin compatible with the standard dual opamp pinout, i.e. the 5532? i would check that first since i seem to remember the NJM stuff being a little wierd like that.

Miko is right, you should start with the summing networks first. If you end up using FET input parts to replace the original opamps, you might get away with losing some of the interstage coupling caps since it seems that the FET inputs are not as sensitive to DC offset and such as the BJT's are.

just be careful soldering and unsoldering as you could ruin a trace or ten. do a pair of channels and A/B them. make sure you do the WHOLE channel or you won't hear much difference..

just a few more ideas.

:thumb:

 

[Rossi]

The NJM4580 chips are SIL packages. The only SIL 5532 and 2114 chips I know of are NJM, too. I would assume that they use the same pinout. But it's certainly wise to double check that.

The reason why I would start with the preamp boards is because they're easier to work on because of their size. Also, I really don't use the MX8000 that much anymore. The preams are among the parts that I sometimes do use. And I think they might seriously profit from better opamps. Among other things, I have an old Ultragain 2000 preamp which uses a similar circuit. But for some reason it sounds much better. One of the main differences being the opamp stage. But actually, one of the main things that I miss on the MX8000 inputs is phase reverse switches. On most mics your headphone signal is out of phase with your voice when you use the MX8000 and hence "somehow" doesn't sound too good. The preamps themselves aren't so bad; it's the phase reversal.

 

[clintrubber]

Yes, I'm missing a polarity switch as well (a grey MX8000 here as well - with a blue meterbridge...).
Didn't the MX9000 had such switches added ?

Bye,

Peter

 

[MikoKensington]

No Polarity on my 9000.