Bob Pease on the New LM4562

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#161
tubee said:
Hi MatchASM

Did you have to pay a lot of shipping/handling fee?

The 2604 was a long time a good upgrade in cdp's for LM833, NE5532, but imo you can then better keep the 5532, less distorsion in treble. I like the OPA2132 more, but still want to try the LM4562.
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I think handling/shipping was around 22 dollars (I estimate less than 20 euros) and they arrived within half a week from Singapore. And you need a credit card.

Is the difference between 2604 and 2132 really big? Because if so, I might try the 2132 for comparison.
 
#163
I replaced my opa2132( fully ran-in) with LM4562HA.
The difference is huge.
OPA2132 appeared to be a bottle-neck for the system which is full of OPA627BM.
LM4562HA, IMO, is up to the standard of OPA627BM and the sound is wide, clear, and dynamic.
It's a very good OPA indeed.
However, the feedback path has to be kept as short as possible for this OPA.
 
#164
I've just ordered some 2132's. I just noticed that before the introduction of the LM4562, the OPA2134 was often considered the "best-sounding" op-amp. The specs are almost the same as those of the 2132, only the input current is a factor 10 lower and the open-loop gain is 10dB lower. So, is this a big difference?
 
#167
2132 vs 2134, BG decoupling

OPA2134 was often considered the "best-sounding" op-amp
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I assume they sound about the same. Will try some 2134's soon. Choose the best opamp for the application.

The THS4032 is only ideal as I/V, see: http://www.diyaudio.com/forums/showthread/t-66526.html

Avoid OP275 btw.

i really like to5s
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Yes those nice & shiny housings 😉

Yesterday i removed the Black Gate N type decoupl. near 2132 opamps in CDP, the player sounded allmost mono with them!!
I know the BG's have to burn in, but sound was so awfull, removed them, did'nt want to wait longer then 2 days.

Refitted my own solution: near opamps 100uF 25V Philips lytic, bypassed with 1uF63V mkt, before them a 3 windings diy bead and a 2 ohm smd res. in series (removed the standard 33 ohm fusible res.) Before bead/resistor is another 1 uF mkt. Now there is roughly a 18dB/okt. ps filtering before opamps. Soundstage wide again!
 
#168
#169
MatchASM said:
I've just ordered some 2132's. I just noticed that before the introduction of the LM4562, the OPA2134 was often considered the "best-sounding" op-amp. The specs are almost the same as those of the 2132, only the input current is a factor 10 lower and the open-loop gain is 10dB lower. So, is this a big difference?
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Hi,

LM4562 is much much better sounding than the OPA2132/4 in a preamp. And OPA2132/4 is good. I'm going to try these in my Marantz CD63 next in place of 2xOPA627. The sound character is pretty much non-existent, making 2134 sound veiled and LM6172 gritty and bright.

Simon
 
#171
Sound of this op-amp is really transparent but it shows potentiality with good power supply and quality components. I'm using it with BGN capacitors as close to this chip as it's possible. DC offset voltage comparing to competition is very low.
 

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#173
Did anyone analyse the reason for the drastic increase of THD+N at lower output voltages ? Is it really the "N - part" that is responsible for it ? The fact that IMD doesn't rise as much with decreasing output voltage increases the hope that this is the case.

Regards

Charles
 
#174
Spev said:
anyone know if the LM4562 is happy running on single supply? I'm using them at the moment with +26v input and they appear ok, but wondered if there's any potential issues I should be aware of?
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Well, according to the datasheet, the NE5532 can handle any input signals between the supply voltages, so I'm guessing the LM4562 can do that too.

If it doesn't get hot, there's nothing wrong with it.
 
#175
I'm using it with BGN capacitors as close to this chip as it's possible.
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BG N type? see post 167, but that was my own experience. Or burn-in was too short, don't know. Imo N's are just a waste of money, better invest that money in better (new & standard) caps overall in ps, better diodes (byv's) and some extra decoupling at chips with 0.1 or 0.22 uF MKT/MKP's. Has anyone here has same sort of experiences? With BG standard caps i had better results btw. 😉
 
#176
phase_accurate said:
Did anyone analyse the reason for the drastic increase of THD+N at lower output voltages ? Is it really the "N - part" that is responsible for it ? The fact that IMD doesn't rise as much with decreasing output voltage increases the hope that this is the case.
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Yes, this is exactly the case. Not all of that is necessarily noise at the chip's inputs; it could also be noise output from the signal generator! Testing distortion at these levels is not easy.
 
#179
BrianDonegan said:
Unless I am mistaken, you want the lowest ESR you can get for this job, so films will almost always be better than an EL cap.
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I thought that small film caps didn't have low ESR, and hence bypassing is somewhat fruitless with anything less than about 1uf. I use 33uF Panasonic Fc under my opamps' legs and that works ok but I think others may sound better e.g. Black Gates.

Simon
 
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