I think i'll stay away from turned pin sockets.
The heading description for one of the sockets was; "Winslow 2.54mm Pitch Vertical 8 Way, Through Hole Turned Pin Open Frame IC Dip Socket, 5A"
I just realised it's referring to the current rating.
Is this critical or something that doesn't really matter?
How do i know what is the correct current for my Quad?
The heading description for one of the sockets was; "Winslow 2.54mm Pitch Vertical 8 Way, Through Hole Turned Pin Open Frame IC Dip Socket, 5A"
I just realised it's referring to the current rating.
Is this critical or something that doesn't really matter?
How do i know what is the correct current for my Quad?
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What does the opamp in a Quad 909 do?
Which parameters of the opamp are most important to achieving that job?
Is any single parameter of the existing opamp not good enough?
Are you able to find a different opamp that meets all the required parameters and manages to improve on any necessary parameters of the Quad selected opamp?
Which parameters of the opamp are most important to achieving that job?
Is any single parameter of the existing opamp not good enough?
Are you able to find a different opamp that meets all the required parameters and manages to improve on any necessary parameters of the Quad selected opamp?
Most manufacturers specify the current ratings of the individual socket pins, like 1A meaning 1 amp which is typical for most dual-wipe sockets. 3A and 5A are the current ratings for some turned -pin sockets such as Mouser stock. What you would do with 5A in an op amp defies belief but surely that's about non-opamp use, I hope.
http://www.mouser.com/ds/2/273/090-259652.pdf
http://www.mouser.com/ds/2/273/090-259652.pdf
Apparently the opamp in the Quad 909 is an integrator in the DC servo loop, and i'm told in theory that changing the opamp shouldn't affect the sound at all. However, i have heard from numerous people who have changed the opamp and state it really does improve the sound. How it may improve the sound is highly subjective, but some say the sound really does change for the better. The original TLC271 is ancient, and yes it works perfectly for its original purpose, but is many decades old and if changing it out for something else can improve the sound i would like to try. I'm aware this may come with a possible risk of damaging the amp, but it's a risk i'm willing to take.
So 5A and 3A should both be ok? The ones on RS components and mouser all said either 3A or 5A.
So 5A and 3A should both be ok? The ones on RS components and mouser all said either 3A or 5A.
I don't think this has anything to do with opamp specification or performance. It's more about about simply swapping op amps (because you can) in the hope of sonic improvement or anything sounding different at all. Most of us will know as stated in #15 that there really is no effect in changing a DC servo opamp provided the circuit still operates the same, maintaining the same DC offset.
In an AB comparison, a listener would not be able to pick a difference but when the time it takes to fit new opamps and listen again is considered, a good proportion of observers will most likely report differences, real or not because their listening disposition is now changed too. Unfortunately, such a fit then listen methodology is a long way from an honest or fair test of anything subtle but as long as experimenters are happy tinkering any way they like and they find others who share the activity, I think that's fine and good for them.
In an AB comparison, a listener would not be able to pick a difference but when the time it takes to fit new opamps and listen again is considered, a good proportion of observers will most likely report differences, real or not because their listening disposition is now changed too. Unfortunately, such a fit then listen methodology is a long way from an honest or fair test of anything subtle but as long as experimenters are happy tinkering any way they like and they find others who share the activity, I think that's fine and good for them.
Absolutely!
I'm, changing over many things including signal caps and also PSU caps. Those things will almost certainly change the sound.
The opamp experiment is something i'm doing just because i'm curious. Logical dictates it shouldn't make any difference with the opamp, but some people say they have tried it and noticed a difference. Is it possible those people are hearing differences that are perhaps imagined or psychological? Absolutely and that may well be the case, but it's also possible it may make a difference. I'm relatively young and have very good hearing, so i would like to try for myself. I actually have two 909 amps so i can do a direct comparison and listen to one amp with new opamp and the other amp with the original opamp in place.
I'm, changing over many things including signal caps and also PSU caps. Those things will almost certainly change the sound.
The opamp experiment is something i'm doing just because i'm curious. Logical dictates it shouldn't make any difference with the opamp, but some people say they have tried it and noticed a difference. Is it possible those people are hearing differences that are perhaps imagined or psychological? Absolutely and that may well be the case, but it's also possible it may make a difference. I'm relatively young and have very good hearing, so i would like to try for myself. I actually have two 909 amps so i can do a direct comparison and listen to one amp with new opamp and the other amp with the original opamp in place.
if the wrong opamp is chosen and as a result it's performance affects the audio, then there could be a change in the audio performance.
A DC servo should have no effect on the audio signal. The only reason for replacing the coupling capacitor with a DC servo is to remove the small effect that a coupling capacitor might have on the wanted audio signal.
If you use that incorrect opamp and it's effect is worse than the effect of the coupling capacitor that it was installed to replace, then you have failed.
A DC servo should have no effect on the audio signal. The only reason for replacing the coupling capacitor with a DC servo is to remove the small effect that a coupling capacitor might have on the wanted audio signal.
If you use that incorrect opamp and it's effect is worse than the effect of the coupling capacitor that it was installed to replace, then you have failed.
Hi Andrew i appreciate what your saying but i'm slightly confused.
The thing i'm contemplating is to replace the old opamp (TLC271) with a more modern opamp (LME49710).
I wasn't intending to place a DC servo where the coupling capacitors go.
I will replace some of the old capacitors with original types, but that's not related to the opamp change over.
The thing i'm contemplating is to replace the old opamp (TLC271) with a more modern opamp (LME49710).
I wasn't intending to place a DC servo where the coupling capacitors go.
I will replace some of the old capacitors with original types, but that's not related to the opamp change over.
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Have a look at this, http://www.diyaudio.com/forums/soli...lls-power-amplifier-book-190.html#post2602945