Using three different op amps?

[Newmarket]

I was talking about these little devils
http://www.tnt-audio.com/jpg/ss3602-dual-discrete-op-amp.jpg

I'll be home in about 2-3 hours. I'll send pictures of the ciruit

Oops, I may have confused things. I wasn't suggesting replacing with discrete op amps at huge expense !!!

What I meant was that OPA2134 might be a good option if you do want to change the op amp and you might get some sonic 'colour' if you drive it hard but I can't vouch for that myself.

As for the 'discrete' approach I meant something like a jfet buffer / gain stage at the front end to introduce some non linearity = (hopefully) 'euphonic' distortion = harmonics that you like.
Not replacing all op amp stages.
Like I said - requires some design knowledge / input and technician skills.
Anyway change the electrolytic caps first.  They age.  Fact !

 

[enginefire]

Makes much more sense!
Those little guys look pretty sweet can you post a link to their seller or creator?  I'm sure they would sound pretty good.  Maybe overkill on this mixer tho?  Definitely lower hanging fruit at better cost value ratio .  of try a pair of channels and see.  Or if you are using it for summing try them out in the master section?  I definitely wouldn't put them in the eq circuit these old Yamaha eqs sound mediocre at best imho, super fancy DOAs won't change that .

 

[Keala]

Makes much more sense!
Those little guys look pretty sweet can you post a link to their seller or creator?  I'm sure they would sound pretty good.  Maybe overkill on this mixer tho?  Definitely lower hanging fruit at better cost value ratio .  of try a pair of channels and see.  Or if you are using it for summing try them out in the master section?  I definitely wouldn't put them in the eq circuit these old Yamaha eqs sound mediocre at best imho, super fancy DOAs won't change that .

http://www.ebay.com/itm/Dual-Discrete-Op-Amp-SS3602-/141461456047
It's a bit expensive imo

these are a bit more budget friendly
http://www.ebay.com/itm/HDAM-Full-Discrete-Single-OpAmp-Module-Replace-AD797-OPA627-NE5534-A8-010-/282280468451?hash=item41b93a1fe3:

 

[Keala]

From 1st glance I'd say they're the yellow gold caps by the pots (0.0018 and 0.0056uf).  Nice that everything is labelled!

Can you remove a channel ?  A picture of the entire top and entire bottom as well as a list of what each pot does would be helpful .

Consider recapping all the electrolytic capacitors

Contact Yamaha service dept online for the schematic.

https://ibb.co/ewGZsQ

 

[PRR]

> Do you mean Yamaha (rather than TASCAM) as the OP's desk is a Yamaha ?

Ah, yes, I get confused easily.

In a certain vintage, a lot of the Yamaha looks like a lot of the Tascam. Except the Yamahas were perhaps a shade better. (Brown chicklets instead of green chicklets.)

I don't think it is begging for mods. But some folks can't resist.

 

[JohnRoberts]

After seeing where this  thread has gone, I suggest going back to putting 741s in there....    (kidding).

JR

 

[enginefire]

At $80 a pop for a dual lol I think I'll never.  To me that is just a little insane, might as well just buy something different that sounds good in the first place.  Or something that is designed for DOA s already...

For your console .  I'm not entirely sure what you need to change.  You have 3 eq pots but 4 of those golden chicklets.  Without a schematic (the 2408 values don't seem to line up) you would be just doing random things.  You're only option really imho is to trace out the circuit a bit.  The 2408 schematic might help you with that but it's by no means a sure thing.  Anyhow Its a total drag to do it the 1st but you will learn a lot and it gets easier too.

 

[Andy Peters]

After seeing where this  thread has gone, I suggest going back to putting 741s in there....    (kidding).

No, he needs to install the LM301!

 

[CJ]

whatever you do, stay away from all the Signetics opamps,  leaves more for me!

 

[enginefire]

whatever you do, stay away from all the Signetics opamps,  leaves more for me!

The ones with the big S?  Whats wrong with Signetics?

 

[CJ]

read the small print!

 

[Keala]

Well.. at this point i might just go out and buy a new console. Heh

 

[buildafriend]

Maybe a higher slew rate for freq above the audio spectrum but that's not this

What is with the 741 talk? Slew rate is so slow it can't pass 4k out IIRC. Why use even bother? They only seem good for a tech history lesson. They got it all on the same substrate, good idea!

5532 is a really good bang for the buck and works great. You'll have a hard time beating it without spending 10 bucks per chip in which case get a DOA kit for 5 more bucks but then you're dealing with DC offsets and higher current draw.. sounds best though imo.

TL072 has voltage noise from FET inputs in the IC, it's a no no imo

Stick with BJT differential pairs on the inputs of your op amps - like 5532

 

[Keala]

Maybe a higher slew rate for freq above the audio spectrum but that's not this

What is with the 741 talk? Slew rate is so slow it can't pass 4k out IIRC. Why use even bother? They only seem good for a tech history lesson. They got it all on the same substrate, good idea!

5532 is a really good bang for the buck and works great. You'll have a hard time beating it without spending 10 bucks per chip in which case get a DOA kit for 5 more bucks but then you're dealing with DC offsets and higher current draw.. sounds best though imo.

TL072 has voltage noise from FET inputs in the IC, it's a no no imo

Stick with BJT differential pairs on the inputs of your op amps - like 5532

Can you link to some 5$ DOA kits? I've mostly found them at 20-30 bucks

 

[buildafriend]

I was trying to imply for 5 bucks more they are 15 bucks each. They are time consuming to build though. If you really want cheap just etch your own boards. There may be some threads on here with free layouts you can use. You'll probably have to order the parts and some transistors have to be matched. You'll also need adapter boards and regulators that have the current to spare.

Really though, just throw 5532s in there think about it, just about every song you hear has probably passed through tons of them.

 

[Keala]

I was trying to imply for 5 bucks more they are 15 bucks each. They are time consuming to build though. If you really want cheap just etch your own boards. There may be some threads on here with free layouts you can use. You'll probably have to order the parts and some transistors have to be matched. You'll also need adapter boards and regulators that have the current to spare.

Really though, just throw 5532s in there think about it, just about every song you hear has probably passed through tons of them.

Do you know about any op-amps that generate a lot of harmonic distortion?
would be fun to test out on a channel to see if it adds some "mojo"

 

[Newmarket]

Do you know about any op-amps that generate a lot of harmonic distortion?
would be fun to test out on a channel to see if it adds some "mojo"

5532 likely good unless input impedance, current draw and DC offsets an issue in this design.

No opamps are designed to produce lots of distortion. Linearity is basically an intrinsic design target. Look at discrete transistor type buffers etc for non linearity.

 

[JohnRoberts]

Do you know about any op-amps that generate a lot of harmonic distortion?
would be fun to test out on a channel to see if it adds some "mojo"

Decide exactly what kind of distortion you desire (harmonic is not specific enough).  There are different approaches to preferentially make some specific kinds of distortion (effects).

I have never once desired more distortion from a design .

Be careful what you wish for, making distortion is easy, but it generally sounds bad which is why designers avoid it. Good sounding distortion is more fleeting and ethereal, some might say an urban myth (or a marketing invention to put lipstick on a pig)..

JR

PS: Vacuum tube overload is considered better sounding than solid state amp overload so preferred by money no object guitar amp crowd.  Maybe put a tube in place of your op amps (kidding... really I'm kidding).

 

[Audio1Man]

Do you know about any op-amps that generate a lot of harmonic distortion?
would be fun to test out on a channel to see if it adds some "mojo"

You may try LM324 as it has low drive and was designed for battery operation.
Duke

 

[Keala]

Decide exactly what kind of distortion you desire (harmonic is not specific enough).  There are different approaches to preferentially make some specific kinds of distortion (effects).

I have never once desired more distortion from a design .

Be careful what you wish for, making distortion is easy, but it generally sounds bad which is why designers avoid it. Good sounding distortion is more fleeting and ethereal, some might say an urban myth (or a marketing invention to put lipstick on a pig)..

JR

PS: Vacuum tube overload is considered better sounding than solid state amp overload so preferred by money no object guitar amp crowd.  Maybe put a tube in place of your op amps (kidding... really I'm kidding).

What i want is odd harmonic distortion.