LM1458 Replacements Guitar Amp

Buckeye Sound · 26th June 2005, 08:17 PM

I typically prefer tube amps, but I have a Music Man amp from about 1979 that sounds great. It has a solid state preamp section and tube power section. The preamp section uses LM 1458 op amps. Any thoughts on better replacements that offer a warm, clean, rich tube'ish sound?

Thanks

darkfenriz · 27th June 2005, 02:22 AM

Don't overvalue the op-amp. Probably you won't hear much difference. Guitar amplification adds loads of harmonic distortion and sound is still 'clean', so only thing I think you may look for is low noise.
regards

anatech · 27th June 2005, 11:16 PM

There really is no point, but NE5532's are cheap and may be quieter. I would not go further than that.

-Chris

Leolabs · 28th June 2005, 01:47 AM

try the old TLO72 too

Original Burnedfingers · 28th June 2005, 02:50 AM

The 4558's are a step up from the 1458's but as Chris mentioned the 5532's are the way to go.

Buckeye Sound · 28th June 2005, 06:47 AM

Being far more familiar with tubes, I inferred from the various negative comments regarding LM1458 and the comments on this board comparing one op amp to another that op amps color the sound much as do tubes. i.e. lots of positive comments about OPA2604, OAP2134, NE5532, and JRC4558. But, based on this feedback, op amps are not a noteworthy factor in the color of the sound in a guitar amp preamp? One is as good as another is for this application?

cpemma · 28th June 2005, 07:13 PM

Quote:

Originally posted by Buckeye Sound
Being far more familiar with tubes, I inferred from the various negative comments regarding LM1458 ...

LM1458 is about the cheapest opamp sold, extra bargain as it's dual, so it's basically you get what you pay for. Things have moved on, even at the budget end. The NE5532 mentioned is usually a drop-in swap and, though double the price, still only about 50 pence/cents.

Fit sockets and try a few.

anatech · 28th June 2005, 11:49 PM

Hey Buckeye,
It's not the sound so much as the amount of noise you hear with no signal. I suggested the NE5532 as it does sound good and is quiet. The TL072 can be quiet depending on the circuit, but the output drive current is lower than the NE5532. Either one should be better in all respects over what you are using. I wouldn't use sockets, but that's your choice. If you do, get some nice Augates. Don't use cheap parts. They will cost the same or more than the op amps. Hmmmmm.

-Chris

Buckeye Sound · 29th June 2005, 03:40 AM

Thanks

So the list to consider is:

NE5532
JRC4558
TL072

Does brand matter?

anatech · 29th June 2005, 08:33 PM

Howdy,
THe 4558 is close to the 1458 you are replacing. Buy name brand only. If the printing is bad and / or it's a brand that is not well know I would not touch it. Basically, if they are being sold cheap compared to the market in your area, they are most likely remarks, pulls or rejects.

-Chris

26th June 2005, 08:17 PM	#1
Buckeye Sound diyAudio Member Join Date: Jun 2005 Location: Here	LM1458 Replacements Guitar Amp I typically prefer tube amps, but I have a Music Man amp from about 1979 that sounds great. It has a solid state preamp section and tube power section. The preamp section uses LM 1458 op amps. Any thoughts on better replacements that offer a warm, clean, rich tube'ish sound? Thanks

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27th June 2005, 02:22 AM	#2
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	Don't overvalue the op-amp. Probably you won't hear much difference. Guitar amplification adds loads of harmonic distortion and sound is still 'clean', so only thing I think you may look for is low noise. regards

27th June 2005, 11:16 PM	#3
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	There really is no point, but NE5532's are cheap and may be quieter. I would not go further than that. -Chris

28th June 2005, 01:47 AM	#4
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	try the old TLO72 too

28th June 2005, 02:50 AM	#5
Original Burnedfingers diyAudio Member Join Date: Nov 2002	The 4558's are a step up from the 1458's but as Chris mentioned the 5532's are the way to go.

28th June 2005, 06:47 AM	#6
Buckeye Sound diyAudio Member Join Date: Jun 2005 Location: Here	Being far more familiar with tubes, I inferred from the various negative comments regarding LM1458 and the comments on this board comparing one op amp to another that op amps color the sound much as do tubes. i.e. lots of positive comments about OPA2604, OAP2134, NE5532, and JRC4558. But, based on this feedback, op amps are not a noteworthy factor in the color of the sound in a guitar amp preamp? One is as good as another is for this application?

28th June 2005, 11:49 PM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hey Buckeye, It's not the sound so much as the amount of noise you hear with no signal. I suggested the NE5532 as it does sound good and is quiet. The TL072 can be quiet depending on the circuit, but the output drive current is lower than the NE5532. Either one should be better in all respects over what you are using. I wouldn't use sockets, but that's your choice. If you do, get some nice Augates. Don't use cheap parts. They will cost the same or more than the op amps. Hmmmmm. -Chris

29th June 2005, 03:40 AM	#9
Buckeye Sound diyAudio Member Join Date: Jun 2005 Location: Here	Thanks So the list to consider is: NE5532 JRC4558 TL072 Does brand matter?

29th June 2005, 08:33 PM	#10
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Howdy, THe 4558 is close to the 1458 you are replacing. Buy name brand only. If the printing is bad and / or it's a brand that is not well know I would not touch it. Basically, if they are being sold cheap compared to the market in your area, they are most likely remarks, pulls or rejects. -Chris

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