Op amp replacement, tantalum caps and slew rates

[PRR]

> API stuff can drive a 75 ohm load with no problems?

Jensen 990 was designed to do that. (Not all "similar to 990" will do that.)

Not for any silly generalization about "sound", though it is true that you don't want an amp to strain. In really serious situations in real professional audio, sometimes you really need line levels over 30dBm terminated both ends. That either means +/-40V supplies, or since you want transformer-floated also, a steep step-up ratio.

 

[Mbira]

This is a great thread-maybe it should be stickied in with the meta-meta-meta?

Learning a lot...

Joel

 

[dramadisease]

im still jaw dropped over the 301 amp
ive got an entire auditronics console with (if i remember exactly) the 301 as the mic pre

prr-> what would you recommend as the proper compensation cap value and proper forward feed cap?

im really curious about using it....i havent gotten the whole board up and running...too many projects..

whats your opinion on how do they sound? is it something where the amp specs well but sounds bad? any comparisons in sound? (im hoping you are going to shout something back along the lines of "boy, didnt you know? they sound like a neve!")

oh i can wish!

=bryan

 

[dramadisease]

*bump*

 

[Eje2005]

I m currently giving my ashly sc-66 a tune up and the thing is packed with 301's, a total of 32 in the filter section, i´m gonna keep them in just to avoid power issues and oscillation probelms,
About 8 of 4558 in the amp section, they are long gone!
swap´d them with 5532s. Goodbye grain!

The caps on the side (compensation caps) of the 301s are ceramics,
Any idea what to change them to? Polyprop, polyester or tantal?
Should i keep the stock value on theese?

- Jonas

 

[Guest]

[quote author="NewYorkDave"]Yes. Until about 1970, that was the usual way to go.

It was typical to employ several of one or two different amp types in a console, with the amps at a fixed gain (usually 40dB) and, when less gain was needed, pads were used.[/quote]

Hmmm.... I remember Altec's micamp where gain was regulated by variable resistor between emitters of input transistors where feedback resistors were connected to as well... Or it was designed in 1970'th?

 

[Eje2005]

The caps on the side (compensation caps) of the 301s are ceramics,
Any idea what to change them to? Polyprop, polyester or tantal?
Should i keep the stock value on theese?


Anyone?

 

[Eje2005]

bump

 

[SonsOfThunder]

I'd say take a look at the Ward Beck 470a module.

schematics here

Peace!
Charlie

 

[ebartlet]

[quote author="Eje2005"]The caps on the side (compensation caps) of the 301s are ceramics,
Any idea what to change them to? Polyprop, polyester or tantal?
Should i keep the stock value on theese?


Anyone?[/quote]

I had wondered the same thing a couple of years ago when I started this thread. I found that it was difficult to find and not cost effective to use anything but ceramic for the compensation caps due to their low value, 39pf in my board...

 

[Eje2005]

thanks man