Yamaha amplifier Upgrade

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Hi
I wish to upgrade my old Yamaha A-560 amplifier. I started for change the OP in the preamp (JRC4559) for a NE5532, because I read that are fast in the spec sheet (Slew rate: 8 V/µS NE5532 – 2 V/µS JRC 4559).
I see here that are many others Ops that are better, like the OPA249, AD8032, or best THS4032 and some LMH-types.
My question will be if this others best Ops perform well in a pre designed in my modest Yamaha amplifier to work with the original JRC4559. If not, I must modify my pre in other way?
Thanks to this excellent forum and for any comments,
Regards.
 
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Hi Macpibe,
Keep in mind that the 4559 is a pretty good op amp. There are many more factors to look at. Having said that, the NE5532 is a good sounding op amp. You could certainly try it. I honestly don't know if you will hear a difference.

Correct me if I'm wrong, but is that op amp used in the phono section? I thought the tone controls were operated in the main feedback loop. If this is the case, I doubt this will make any difference on high level inputs. I'm just going off memory here.

-Chris
 
Thanks Chris,
And yes, this op amp is used in the phono pre amp section.
Unfortunately I don’t have the schematic circuit of this amplifier (If any can tell me where find this in the web..thanks…) and can’t see how the tone control works..
But, in any case, you think that I can’t hear the difference between others (best) OP amps?
Thanks again,
Carlos.
 
Gracias Ivan, intentare por ahi...
And for Chris (if you want answer) or anybody, in a phono pre amp design like this (attachment), which OP amp will be better to replace the original JRC4559D? an OPA2134 (FET input) or an LM4562 ?
Many thanks.
 

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Hi Carlos,
That's a hard question to answer. The dual fet pair really loosens the job on the op amp. In this circuit you will need good drive capability. Super high slew rates are not critical either. Try them both if you want. I don't know how it will react to a fet input, but it may work just fine. Measure the hiss level on the tape out when you try them. Also, listen and pick what you like the best. Don't worry if you don't hear a difference either. Watch for oscillations.

I'd be interested to know if you do hear a difference.

-Chris
 
Don't change The OpAmp...

Macpibe:

Change of the opamp involves change resistors, condensers and other components. Every opamp has your own values for that elements. A direct change of the opamp, results in a uncertain operation, due to the differents values of such components. Maybe, a good tweaking in the phono stage, is to change the carbon resistors in the signal path, by metal film ones (if not metal film already!), with the same values!. This results in a lower noise figure. Other possible enhancement, is to change the coupling capacitors, but depends on the kind and values used in the original circuits, to choose a new (and better) ones; ..more on next post...
 
Cont. #1 due to character restrictions.-

this will give you, if the change is from electrolytics to oil capacitors, polyester or the latest multy-layer, all non-polar types, a warmest and detailed sound, that let' you to ear a "new things" from your favorite music. Take care when working on this stage, 'cause is too much delicate due to the small magnitude of the signals handled, and, in this circumstances, the precision of the designg is in compromite at every modification.
So, search for the schematics, and after locate in example, opamps in the line of the general preamp, tone control, and buffers.
In fasct, yes, it's a very, very good idea to replace opamps, but onnly if you are absolutly shure about the values of the peripheral components of the new device, and if it do not affects the overall performance of the stage involved.
 
Cont. #2 due to character restricions.-

Last words:

-Always use lead-free solder, it's made with 96% tin, and 4% silver... Believme, it makes a big, really big difference in audio solderings... I've used, as a reference, the RadioShack Cat. No. 64-026, but there are some produced in Brazil, wich works great too.

-Search for mods on other audio components, such CD players or tuners, wich includes enhancements on the output audio signal path, useful with amplifiers, and preamplifiers.
Cheers.-
 
Forget to mention

Yes, again, Macpibe, your'e right about to change ampops.
In this days, there are opamps, with a slew-rate up to 7000 V/ìS, but pay attention: are selected units, expensive and hard to find. The commercially available are 1000- 2000 V/ìs... Nice figure, uh?
Would be nice to have this devices, and all the info needed to use them properly to tweak our "babies" ...
 
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Hi zeppy2033,
In this days, there are opamps, with a slew-rate up to 7000 V/ìS
Those are current feedback op amps, a different circuit completely. I haven't heard of those high slew rate figures, but they may exist. Some of the fast voltage feedback op amps do require more careful bypassing. Besides, you have to look at noise figures too and the faster op amps are usually not the quietest.

-Always use lead-free solder, it's made with 96% tin, and 4% silver... Believme, it makes a big, really big difference in audio solderings
Okay, now you've really lost me. I've used many different types of solder an have yet to hear any minor difference. Possibly redoing bad connections is what you are hearing. These other solder types require a higher temperature to work at. This is hard on PC boards and components.

Be very careful when modifying equipment. Most "improved" equipment I see has had rough work done to it, and has been worked on by someone who does not fully understand what they are doing. Some improvements can sometimes be made, most people go way too far. They don't know when to stop and cause problems. Changes will always be heard by those who do the work or have a stake in a unit when there may not be a change, or the change isn't for the better.

-Chris
 
OK.-

Yes, anatech, i agree in everything on your post.
I ve founded information about that 7000 V/micro s in the JRC web page a couple of years ago. I´ve downloaded some pdf documents about that devices, but unfortunately are in my old PC, wich is out of order, and cant' take them.
Take a look at: http://www.njr.co.jp/index_e.htm
About the lead-free solder (the RadioShack mentioned earlier), i've used with my standard 25W or 30 W Goot solder iron, in RCA or TRS plugs and jacks involved in lots of audio connections, inside equipment, or making connection cables or extensions. it results in a firm sound, more detail in the wave shape..You'll can re-discover your existing CD's, the sound from your tuner and other sources of sound.
The difference in speaker connections is greater than the single ended (RCA-To-RCA) connections.
You need just to spend a few dollars in that lead-free solder, and try.
You won't be sorry.
Best regards.-
 
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Hi zeppy2033,
I have tried. No difference.

Besides, if you want to improve your speaker connection you should be using some type of spade connector with brass binding posts. The greater surface area will drop connection resistance far more than any solder would. Also, one would expect large differences in speaker wire sound simply due to wire size. This has been proven to not be the case above some minimal size (for the application).

I use a controlled temperature station. I don't consider a 30 W iron to be able to deliver sufficient heat to the joint when using silver based solder. Most controlled temperature irons are capable of delivering 50 ~ 60 W of heating power to the connection. Short, wide tips are the best for this. I prefer a short, wide tip for most of my work, including surface mount work.

I suspect the popular press is having the greatest effect here. ;)

-Chris
 
Ok part II

Maybe the differences between 60/40 and lead-free solders, are noticeable only for audiophiles like me. Technically speaking, both of them are corrects, if done properly of course.
Also, differences between different kind of connections, such the ones included with the sound sources (Tuners, Cassette decks, CD players), and Van Den Hul, Monster Cable and others, maybe are a matter just to audiophiles too.
Not all the people can see differences between them. And keep in miind, that cable and wire makers, like Van Den Hul and maybe others too, use exclusively lead-free solder to make their connections. This is, IMHO, one of the main causes of the high quality of their cables.

Pardon by the errors in the writing.

Best regards.-
 
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Hi zeppy2033,
Maybe the differences between 60/40 and lead-free solders, are noticeable only for audiophiles like me.
I strongly doubt this. Sorry, and no offense.

When you work on a device, the very best judge are small children. Either that or the rare wife or friends that are trying not to hurt your feelings. Most of us suffer from preconceptions about how we expect, or want something to sound.

I never listen to my own work before deciding whether it is good or not. I can not be objective, nor can most of my friends. This is why I wrote "I suspect the popular press is having the greatest effect here." . I knew you would respond the way you did. :D You are in the same boat my friend.

Popular mystic and press are reasons why the NAIT was well received. They say many of the same things you did. Now, had they used silver solder, there would be a NAIT in every high end shop today! So powerful is the underground press.

There is one good reason to use silver solder. It's strong and great for repairing jewelery. So for added strength you could use it in electronics. Lead will bring less trouble than tin. Read up on reliability problems with lead free solder. The military and life support products may continue to use it.

Anyway, I don't want to debate this. If it's good for you - fine. Don't incite others to perform unnecessary and possible harmful work. Most techs can't solder properly. Having them work with silver - tin is begging for trouble.

-Chris
 
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