Vintage Synth Repair

I have just had a quick look in my box of opamps and have both the RC4558
and the MC1458 which are equivalent and I can get hold of these still for
pennies, but the suggestion that you look at the Ti TL opamps is worth
considering as they are not much more expensive and do have lower noise, I
used to reduce the noise in some of the old mixing desks.

 

Many thanks

 

John Rose

 

(www.astrodevelopments.com)

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of jammie
Sent: 06 January 2013 17:19
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Re: Roland JX3P Faulty

 

  

the 4558 op is a very noisy opamp

 

you can change them for the tlo8/7 series dual opamps

 

is it a dip or a ziff 9pin ic

 

as in the korg dss1 they are ziff 9 pins 

 

i exchanged mine for the ones used in the korg trinity the 

 


UPC4570HA made by nec


jrc are a good make if you can source them

 

the 4558 has a very rubbish slew rate and are noisy

 

but becuase of this they make great fx pedals as fast transients can distort


----- Original Message ----- 

From: Nick <mailto:mckenzie126@...>  

To: vintagesynthrepair@yahoogroups.com 

Sent: Sunday, January 06, 2013 3:49 PM

Subject: [vintagesynthrepair] Re: Roland JX3P Faulty

 

  

Hello all. Yep there were multiple hairline cracks, all fixed now with all
control restored.

I do however need to replace the (Sharp)IR94558 op amp in the mixer section
(IC1) as it's crackling. I can get a new Sharp IC but it's rather expensive.
I'm inclined to stick with sharp but would anyone perhaps suggest using the
cheaper JRC or the like?

Thx

--- In vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> , Nick Bell wrote:
>
> Thanks all for your input, really helpful & appreciated. Will report back
with any successful/unsuccessful repairs.
>