Looking for Carlos FM
Carlosfm,
We need your help to upgrade a mixing console that uses TL072's to something better.
Sent you two e-mails but no reply as yet. Could you give us a hand? From your replies here at the board on opamp upgrades, we know you can do it. Thanks a MILLION.
Donnie D. in USA.
Carlosfm,
We need your help to upgrade a mixing console that uses TL072's to something better.
Sent you two e-mails but no reply as yet. Could you give us a hand? From your replies here at the board on opamp upgrades, we know you can do it. Thanks a MILLION.
Donnie D. in USA.
Hi Donnie,
I'm sorry, but on the last days it has been impossible to read e-mails on time.
I'm very very busy at work, and it will last for some months.
I only have some couple of hours at night for my things...
Why don't we discuss that here publicly, on this thread?
I can't help you as fast as I wish, it can take some hours to answer, but there's much more people around here that can give you a help.
Please post a suggestion for a better title for this thread.
It has nothing to do with mixing desks.
I think the moderators can change the title with your suggestion.
I'm sorry, but on the last days it has been impossible to read e-mails on time.
I'm very very busy at work, and it will last for some months.
I only have some couple of hours at night for my things...
Why don't we discuss that here publicly, on this thread?
I can't help you as fast as I wish, it can take some hours to answer, but there's much more people around here that can give you a help.
Please post a suggestion for a better title for this thread.
It has nothing to do with mixing desks.
I think the moderators can change the title with your suggestion.
Oh, I see now. I did misunderstand the concerned tone in your reply
Sorry 'bout that. I just didn't want any misunderstandings to occur! We have enough of those, dont we?Come to think of it, you have given a lot to this community! Thanks a lot for that, Carlos. I am sure a lot of DIY'ers benefit from your contributions. Just take a look at the 3886 snubbered amp
Also your thoughts on the GC preamp have had quite an impact. Great stuff Steen
Mixer upgrade specs and information
Carlos,
The mixer, an AMEK TAC Scorpion-II from 1990, uses TL072's throughout. There are two sets of modules we would like to upgrade 1101 and 4001. The 1101 is the input module with routing, eq and channel assignments. The 4001 is the stereo master buss output module that sums all the signals from each channel to a two channel output. The console does use faders, but don't know the maker of the ones currently installed. Would pots really make that much of a difference? We don't have much of a budget. So opamps, caps, resistors and wire is pretty much all we can swing right now. But please state where you feel we could obtain the best sound upgrade possible with what we have. We could send you the schematics so you can see what we are working with. We were mainly concerned that when you mix at line level, the signal was coming though a mic amp that was padded to line level. Got rid of that mic amp and put a line input module there so the board is now just line input only. We use external mic amps when/where we need mic amplification. Opamps suggested include OP275's for the 1101 lineamp stage, LT1352's for the 1101 eq section, and OPA2134's for the main output section on the 1101 channel strips. OP275's were recommended for the entire master buss output module. We appreciate whatever you can do to assist us in thhis sonic upgrade. Let us know if you need any additional information or details. Just want the best possible sound we can get from what we have now. Thank you all!
Carlos,
The mixer, an AMEK TAC Scorpion-II from 1990, uses TL072's throughout. There are two sets of modules we would like to upgrade 1101 and 4001. The 1101 is the input module with routing, eq and channel assignments. The 4001 is the stereo master buss output module that sums all the signals from each channel to a two channel output. The console does use faders, but don't know the maker of the ones currently installed. Would pots really make that much of a difference? We don't have much of a budget. So opamps, caps, resistors and wire is pretty much all we can swing right now. But please state where you feel we could obtain the best sound upgrade possible with what we have. We could send you the schematics so you can see what we are working with. We were mainly concerned that when you mix at line level, the signal was coming though a mic amp that was padded to line level. Got rid of that mic amp and put a line input module there so the board is now just line input only. We use external mic amps when/where we need mic amplification. Opamps suggested include OP275's for the 1101 lineamp stage, LT1352's for the 1101 eq section, and OPA2134's for the main output section on the 1101 channel strips. OP275's were recommended for the entire master buss output module. We appreciate whatever you can do to assist us in thhis sonic upgrade. Let us know if you need any additional information or details. Just want the best possible sound we can get from what we have now. Thank you all!
Re: Mixer upgrade specs and information
Konnichiwa,
I think your first step is to obtain full schematics for the desk. As the TL072 has a high input resistance at DC and low leakage current the manufacturer may have taken advantage in the fundamental design of this feature. Also, they mahe have (for example) used combined circuits with added discrete components in either input or output stages ahead off or after the TL072 where a simple swap of one op-amp for another type may lead to instability.
Next you must understand that there is no "universally good" Op-Amp. Further, virtually ALL Op-Amp's vounted for audio applications by their makers are actually useless junk with severe colorations and not good sound at all and equally with very poor measured performance. Examples include the Burr Brown OPA604/2604 and AD OP275.
Some of the best available "Audio" Op-Amp's are actually high performance video types of notional cost, however they demand attention in the implementation.
If you really wish to obtain higher performance from your mixer and not just change the sound a little a rigerous design analysis is the first step. Then you can decide what changes are most aproriate to improve the performance of the Mixing desk.
Sayonara
Konnichiwa,
donnie7 said:
I think your first step is to obtain full schematics for the desk. As the TL072 has a high input resistance at DC and low leakage current the manufacturer may have taken advantage in the fundamental design of this feature. Also, they mahe have (for example) used combined circuits with added discrete components in either input or output stages ahead off or after the TL072 where a simple swap of one op-amp for another type may lead to instability.
Next you must understand that there is no "universally good" Op-Amp. Further, virtually ALL Op-Amp's vounted for audio applications by their makers are actually useless junk with severe colorations and not good sound at all and equally with very poor measured performance. Examples include the Burr Brown OPA604/2604 and AD OP275.
Some of the best available "Audio" Op-Amp's are actually high performance video types of notional cost, however they demand attention in the implementation.
If you really wish to obtain higher performance from your mixer and not just change the sound a little a rigerous design analysis is the first step. Then you can decide what changes are most aproriate to improve the performance of the Mixing desk.
Sayonara
The Tac Scorpions are very nice desks, I used to regularly use the monitor variant.
If you're not happy with the sound, I suspect it is just age that is the problem, not the basic design.
Rather than getting into swapping opamps, you would be much better off going for a blanket replacement of all the electrolytics, and a good cleaning of all the pots. Oh, and reflow the solder around all the pot and off-board connectors.
If you're not happy with the sound, I suspect it is just age that is the problem, not the basic design.
Rather than getting into swapping opamps, you would be much better off going for a blanket replacement of all the electrolytics, and a good cleaning of all the pots. Oh, and reflow the solder around all the pot and off-board connectors.
Donnie, the TL072s are are fet-input op-amps.
As Kuei says, without a view of the schematic we have to stick with similar op-amp types.
Maby instead of posting the entire schematic you could just post a .jpg with the module being discussed.
Stay clear of the OP275, it sounds really nasty in the midband and treble.
Specially the ones from Analog Devices.
The OPA2134 is a good option if we don't know the schematic.
Otherwise the LM6172 or the AD827 could be used.
As Kuei says, without a view of the schematic we have to stick with similar op-amp types.
Maby instead of posting the entire schematic you could just post a .jpg with the module being discussed.
Stay clear of the OP275, it sounds really nasty in the midband and treble.
Specially the ones from Analog Devices.
The OPA2134 is a good option if we don't know the schematic.
Otherwise the LM6172 or the AD827 could be used.
There are some restrictions:
The file size should be max. 100k and not bigger then 800x600.
You can attach the file located on your local harddisk in the "Attach file" box.
You can also upload it to your or someone else’s website and provide the link in your post. There's no file size limitation then.
Hugo
The file size should be max. 100k and not bigger then 800x600.
You can attach the file located on your local harddisk in the "Attach file" box.
You can also upload it to your or someone else’s website and provide the link in your post. There's no file size limitation then.
Hugo
Re: Best way to post schematics...
Konnichiwa,
You can place quite large graphic files on the Imageshack server .
Best format for schematics are grayscale .gif or .png bitmap files.
Sayonara
Konnichiwa,
donnie7 said:
You can place quite large graphic files on the Imageshack server .
Best format for schematics are grayscale .gif or .png bitmap files.
Sayonara
Mixing Console Schematics...
Members,
Hope you can read them. The 1101 is the input module. The SSM2015 mic amp has been taken out and replaced with a line input module. The 4001 is the master stereo mix output module. Whatever you can suggest for best possible sound upgrade, we would like to hear from you. Want the best we can get from what we have in this mixer. Thank you all! Maximum Respect. Donnie Dixon.
Members,
Hope you can read them. The 1101 is the input module. The SSM2015 mic amp has been taken out and replaced with a line input module. The 4001 is the master stereo mix output module. Whatever you can suggest for best possible sound upgrade, we would like to hear from you. Want the best we can get from what we have in this mixer. Thank you all! Maximum Respect. Donnie Dixon.
Attachments
Hi Donnie,
what amount of work are you prepared for?
Do you consider replacing the OpAmps only (as this is what you've asked for) or would you like to review the other components, too?
First off, the LT opamps mentioned in the schematic are not the worst in the world (but not the best either, of course). I also recognize that all component descriptions that have been written by hand seem to be recommendations by someone. Those recommendations look allright, but it would be good to know what's to be replaced there.
A couple of recommendations to make our work easier:
- please also post the schematic of the power supply, as this is the point to start from;
- please take photos and post them here, as people occasionally ask for details;
- please actually count the number of every respective component type that has to be replaced, as you might be surprised by the overall cost of your project!
Hope, this helps,
Sebastian.
what amount of work are you prepared for?
Do you consider replacing the OpAmps only (as this is what you've asked for) or would you like to review the other components, too?
First off, the LT opamps mentioned in the schematic are not the worst in the world (but not the best either, of course
). I also recognize that all component descriptions that have been written by hand seem to be recommendations by someone. Those recommendations look allright, but it would be good to know what's to be replaced there.A couple of recommendations to make our work easier:
- please also post the schematic of the power supply, as this is the point to start from;
- please take photos and post them here, as people occasionally ask for details
;- please actually count the number of every respective component type that has to be replaced, as you might be surprised by the overall cost of your project!
Hope, this helps,
Sebastian.
- Status
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