Moby

Re: LM301 substitution
« Reply #20 on: December 03, 2020, 01:39:33 PM »
Hi all

I have consoles that use the 301 which is now obsolete in dip8 package (soic seem to stay alive?)
The LM301 is used in a specific way I don't remember to see elsewhere, where the input stage is bypassed and a discrete differential pair is used in place and sent to the output stage via comp/bal pin.

I'm not expert at all in opamp topology/design and like to know what other of opamp is able to be used like that.

Here the idea of discussion is not to replace for "better" opamp, I have no complain about the sound of my 169 and 289, but anticipate a possible substitution when my spare spent out or when NOS stock get completely overpriced...

Best
Zam
LM301 DIP8, how many pieces you need? I think I still can buy it locally.
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com


robovox

Re: LM301 substitution
« Reply #21 on: December 03, 2020, 11:04:29 PM »
BGMicro shows stock on these at a reasonable price.

https://www.bgmicro.com/ICSLM301.aspx
I have an electric grandpa bed that talks to me while I sleep.
                                                              --Dean Venture

Re: LM301 substitution
« Reply #22 on: December 04, 2020, 06:02:14 AM »
Hello

LM301 DIP8, how many pieces you need? I think I still can buy it locally.

BGMicro shows stock on these at a reasonable price.

https://www.bgmicro.com/ICSLM301.aspx

Thanks to both of you for the help.
I should have enough spare for the moment.

Best
Zam

diggy fresh

Re: LM301 substitution
« Reply #23 on: December 24, 2020, 03:08:48 PM »
I'm not good enough to contribute too much but i think the Ward beck m460 and m470 preamps uses the lm301 in a similar way, bypassing some of the limitations of the internal stuff with discrete parts around it. I have dug a little bit around to find a way to upgrade the lm301 because of the bad reputation but haven't come to any conclusive info yet.  I'm very interested to know if anybody has an idea or tried something.
English is my second language, apologies

Autodidact audio geek, constantly learning.

Very interested in old technology, i mostly learn from the info you guys share on here, so thanks!

Re: LM301 substitution
« Reply #24 on: April 02, 2021, 11:01:29 AM »
BGMicro shows stock on these at a reasonable price.

https://www.bgmicro.com/ICSLM301.aspx

Has anyone tried these in a Studer 169 - 269 ?

Re: LM301 substitution
« Reply #25 on: April 03, 2021, 12:32:01 PM »
Has anyone tried these in a Studer 169 - 269 ?
yes.
circuit critique welcome.

thanks !
drawing revised.
« Last Edit: April 03, 2021, 02:23:10 PM by gridcurrent »

JohnRoberts

Re: LM301 substitution
« Reply #26 on: April 03, 2021, 01:29:52 PM »
yes.
circuit critique welcome.
well that schematic looks wrong... The input LTP (long tail pair) needs to use PNP devices for that PS orientation.

JR
[edit- well now that schematic input pair looks like it was fixed (changed to pnp)... /edit]
« Last Edit: April 05, 2021, 11:29:12 AM by JohnRoberts »
Cancel the "cancel culture", do not participate in mob hatred.

Re: LM301 substitution
« Reply #27 on: April 05, 2021, 10:18:18 AM »
The NE5534 is not the right substitute. Input offset current and Input bias current are higher (around factor of ten) then the LM 301. The best way ist to use an SOIC to DIP-Adapter.
Alternatively you check the use of the LT1122 with higher slew-rate or the OP42 with higher slew-rate and symmetrical slew-rate.
Best regards!
jokeramik

jacomart

Re: LM301 substitution
« Reply #28 on: April 05, 2021, 08:16:57 PM »
yes.
circuit critique welcome.

thanks !
drawing revised.

Honestly the class AB output buffer for me isn't very appealing.
Cheers
J.

JohnRoberts

Re: LM301 substitution
« Reply #29 on: April 06, 2021, 09:26:39 AM »
Honestly the class AB output buffer for me isn't very appealing.
Cheers
J.
Class AB output stages are extremely common especially inside ICs to reduce power dissipation.

JR
Cancel the "cancel culture", do not participate in mob hatred.


jacomart

Re: LM301 substitution
« Reply #30 on: April 06, 2021, 01:15:29 PM »
Class AB output stages are extremely common especially inside ICs to reduce power dissipation.

JR

I agree, but for a discrete-elements realization I would prefer to use class A, but that's just my opinion.
Cheers
J.

abbey road d enfer

Re: LM301 substitution
« Reply #31 on: April 07, 2021, 03:02:59 AM »
The NE5534 is not the right substitute. Input offset current and Input bias current are higher (around factor of ten) then the LM 301.
I don't get it. In this application, the input devices are bypassed and replaced with discrete transistors, so input offset and bias currents are not anymore chip-dependant.
I'm too lazy to ascertain it would work, though.
For most of the circuits in these Studer mixers, the LM301 could be subsituted with 5534 without problems. Even with an order of magnitude higher, input offset and bias currents are not a concern, except in the limiter side-chain, where a FET opamp would be better..
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


 

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