[donnie7]

Hello Prodigy Pro Members, We are a self funded school to keep kids off the streets in Boston and want to upgrade our console for the best possible sound. The 1101 input module, buss 3101 module and 4001 stereo master modules are most important. I have 25+ years in audio engineering and DIY skill-sets. Would like your honest opinions on this issue. The console uses TL072's throughout. Was wondering if we should use all OP275's for the 1101 input modules. Or use OP275 selectively for input/outputs and use the upgraded TLE2072's in the EQ section on the 1101 input modules?

Could we use BB OPA2604's or OPA2134's in the 3101 buss/subgroups and 4001 master output section? The goal here is the best possible sound quality without creating power supply overloading or circuit stability issues due to faster OPA's. Let us know if you need any more info to make a proper selection. Keep up the great audio and engineering work everyone is doing. Looking forward to your reply.
With respect, Donnie Dixon.

[Svart]

opa2604 is a good replacement for the tl072, however with any higher speed opamp you are going to run into the problem of taxing the power supply unless you know for sure you are running within acceptable limits.

I know i've seen some other discussions about this model and the upgrades that are possible, do a search and you might find out more specific info.

TI claims that the tl052 is a higher quality replacement for the tl072/82 however i have not used these in the audio chain, only servo apps.

The Tl0xx are all FET input opamps.  the FET input tends to make dc offset kind of irrelevant to a point which is helpful when upgrading but can cause much trouble if you try to use a BJT input opamp in it's place.  A general rule of thumb is FET for BJT NOT BJT for FET however as in anycase, the rules can be changed.

[TedF]

As Svart so rightly says, be careful with replacing TL0XX with so called 'low noise' devices, you could easily run into offset problems... I hit that myself recently on one of my own designs; had me fooled for a few minutes. :oops:

It's worth thinking about using TL062 (or TL064) on output stages.  The lower operating current can improve power supply decoupling, and the output stage is superior to the 72 in low gain applications.  At audio frequencies and at low gains I like the 62 better than the 72.

[henk]

Hi

You can use the opa2604 but if you dont have the money than try the mc33078 , it has transistors on the input instead of fet.
When you start put in nice sockets so you can test it out witch one works best.

[smallbutfine]

For nice sound you could test OPA2227 for the TL072. I made very good experiences with them as drop in replacements. OK, not cheap...
I also tried MC33078 as a drop in in some applications...sounds good, is cheap, MAY work (?) in your circuits...one of Jakobs all time favourites i think :grin:

Kind regards

Martin

[peranders]

OPA2134 may also be good. EDIT: as you already have mentioned.  :grin:

[TedF]

The MC33078 is a bit of a TFPRO secret weapon..... it's a chip that has good low noise qualities, and doesn't 'go funny' when it's asked to drive anything lower than 10Kohms.  But choice of IC is only part of the performance picture; gain structure, power supplies and layout are all equally or more important.
The 'industry standard' for all but the most expensive equipment is still the TLOxx which may be a reflection of cost pressures; but used intelligently, in the right places they are fine.

[Svart]

the MC33078 and mc33078 are excellent Opamps, however as with any BJT input opamps replacing FET inputs opamps, we need to double check the audio path to make sure that there is minimal DC offset or we need to introduce coupling caps at key areas if they are not already there...


 :guinness:

[moamps]

Hi,

I have some experience with the TAC-Scorpion (not ver. II, though). It is loaded with moderate-quality elcos, which means that replacing TL072s with BJT opamps would not introduce any significant DC shift-related problems. Anyways, I would rather suggest replacing electrolitic caps with better ones and, if the console has Alps faders, replacing exsisting faders with P&Gs.

Regards,
Milan

[clintrubber]

As Svart so rightly says, be careful with replacing TL0XX with so called 'low noise' devices, you could easily run into offset problems... I hit that myself recently on one of my own designs; had me fooled for a few minutes. :oops:

It's worth thinking about using TL062 (or TL064) on output stages.  The lower operating current can improve power supply decoupling, and the output stage is superior to the 72 in low gain applications.  At audio frequencies and at low gains I like the 62 better than the 72.

Excuse me for bringing the up again, but does anyone have some datasheet of the TL06X with some THD-info or otherwise ? It was so absent in the datasheet that I have that I started to suspect something... This combined with having it seen it in a cheap phantom powered DI made me think it was meant for low-current consumption and just tolerating the so-so performance.
But likely not - reading the above is another story.


BTW+FWIW, talking about TL0XX:
http://www.dself.dsl.pipex.com/ampins/webbop/052.htm

Bye,

  Peter

[jetboatguy]

I chose the Burr Brown OPA2604 opamp...


I did a light swap in my Tac/Scorpion about 3 months ago... I only swapped out the top TL072's in each input channel, it's labelled U2 beside the socket in each channel... I have a 32 input channel. I also swapped out all the TL072's in the aux master fx/section and I also swapped out a bunch in the master bus section as well... so a total of aprox' 46 OPA2604 were replaced without power supply issues.

This mod yielded major sonic improvements, when you start stacking the mix you can really here the differences... smooth high freqs and solid low end, more clarity and less muddy coloration, now I know what techs are talkin' about when they say faster opamps.

[clintrubber]

I did a light swap in my Tac/Scorpion about 3 months ago... I only swapped out the top TL072's in each input channel, it's labelled U2 beside the socket in each channel...

Uhh, funny to see opamps in a socket labelled U2... one would expect a delay-chip  :grin:
 :wink:


Sorry

[TedF]

BONO! :razz:

[tony dB]

if the console has Alps faders, replacing exsisting faders with P&Gs.

Milan

Is there quality difference to be heard between NEW Alps or P&G faders?
Does any of you know cheaper source for Alps or P&G faders? I might need 98 of them in the near future.

[Brian Roth]

TI is suggesting this family as an upgrade:

http://focus.ti.com/lit/ds/symlink/tle2072.pdf

Never tried them, and since they have higher bandwidth, then HF oscillation could be a possibility in a given circuit.

Bri

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