Another Amek Tac Scorpion overhaul!

[Eliani]

I'm interested in 4 of the boards.

PM

 

[Eliani]

Rev004 board just in!

 

[craigaudio]

Congrats on the purchase!

My colleague who I had loaned mine to just brought it back. Sounds like you got a good one, as did I. MINT condition, I re-capped the power supply, master section and 2 channels with added Langley line mods. Was going to do the full 16 until I heard about Eli's mods. After checking the sound cloud page, if I can afford it, I'm going with Eli's stuff. Sounds fantastic.

How does your board sound after the upgrades?

Massive improvement. Much more depth and clarity plus a slightly extended low end. As Yves said, no character to talk of really, just much cleaner. I would have finished the full 16 if it were not for the Eli boards....I want mojo!

 

[Eliani]

Ok, I tried recording some more sounds... no more comparison just the difference between Gar1731 and Gar2520 on the Diff_Rev004 boards!!

SOUNDCLOUD

 

[Eliani]

I just built 10 Gar1731 DOA's!! Between taking care of the kids and work it took me more then a full day! After a while you start staring at those small solder pads as if they are one! But I managed to finish them before the kids woke up this morning!!

If anyone is interested in parts kits, PCB's or drop-ins, check the store at Eli-Audio.com!
I might have to start an official help thread over here because I've sold quite a few already!

So together with the gar1731 on the 2-aca-bo and a couple of gar2520 on the channel-strips the DOA count is 18 in this little scorpion! My plan is to finish 12 ch gar1731 and 12 channels gar2520 by the end of august, so Jeff you might expect another order soon! Then maybe if the Belgian customs don't take three more weeks to check the goods, as they always do, I might have this baby done before the ends of time!

 

[bluezplaya]

I just received the boards today. Thank you! They look great!

 

[bluezplaya]

What are the values for the resistors and caps for the boards? I've got a couple of 1731 op amps I built from a few years back that I'm going to put one these and test out in my Scorpion. Anxious to hear it!

 

[bluezplaya]

Got my 4 boards put together and ready to mount to the S1000 channel strip. Which components should be pulled? Should I follow the instructions from Audio Maintenance website?

 

[Eliani]

Got my 4 boards put together and ready to mount to the S1000 channel strip. Which components should be pulled? Should I follow the instructions from Audio Maintenance website?

How about this?
Eli-Audio.com Diff.Rev00x OST
I'm slowly adding information, but everything should be in there, be sure to post some pictures of your modifications!!

 

[critterkllr]

Have you had a chance to swap any chips yet? On the input strips, I put LME49720s in U4 and U5 along with OPA2134s in U2 and U3.

The LME49720s definitely helped bring back some highs and lows along with getting rid of a bit of a "telephone" quality. But, IMO the biggest difference came replacing the EQ chips. A/Bing back and forth makes the old EQ seem like a cheap toy.  Not a subtle difference like I expected!

 

[Eliani]

Have you had a chance to swap any chips yet? On the input strips, I put LME49720s in U4 and U5 along with OPA2134s in U2 and U3.

The LME49720s definitely helped bring back some highs and lows along with getting rid of a bit of a "telephone" quality. But, IMO the biggest difference came replacing the EQ chips. A/Bing back and forth makes the old EQ seem like a cheap toy.  Not a subtle difference like I expected!

I used the LME's in the U5 position, other than that I did not switch any opamps yet. I beleive the 2520 differential mod opens this channelstrip up a lot more than any other mod can! Together with a full recap you're golden!!

I'm thinking about making a second 2520 mod to my channelstrips as in fader booster. And building a complete custom master section too, I really don't like that skinny master section, so I might use 5 slots and incorporate the 4 busses into this new section... Add some more iron, maybe a buss compressor like the gssl 4000... Open for comment!

 

[critterkllr]

I used the LME's in the U5 position, other than that I did not switch any opamps yet. I beleive the 2520 differential mod opens this channelstrip up a lot more than any other mod can! Together with a full recap you're golden!!

I'm thinking about making a second 2520 mod to my channelstrips as in fader booster. And building a complete custom master section too, I really don't like that skinny master section, so I might use 5 slots and incorporate the 4 busses into this new section... Add some more iron, maybe a buss compressor like the gssl 4000... Open for comment!

I'll be adding a couple of your inputs this weekend hopefully. I'll let you know the results and see if the EQ Opamps still make as big of a difference. I only have two 2520s so I'll be waiting for Jeff to get back from Nashville before I can finish anymore.

I'm not sure if the Scorpion I is that different in the master section from the Scorpion II. If you've already replaced the summing with The 2 channel ACA, what else is left? After that is your monitor amps and those should be as clean as possible right?

Could the ACA from Classic API be adapted to use on the individual buses? I haven't had much time to go over the schematics and see how they work.

I thought about adding an internal GSSL, but opted to just go with a separate unit in the rack. Sure, a separate PSU and case is needed, but you'll get more flexibility and it maintains some resale value.

 

[critterkllr]

I'm going to retract my original statement. There was something wrong with the original 2520s I was using. The channels now have a bit more character. It sounds like the mids are more forward, less low end and a blanket it taken off of the highs.

 

[critterkllr]

I'm thinking about making a second 2520 mod to my channelstrips as in fader booster. And building a complete custom master section too, I really don't like that skinny master section, so I might use 5 slots and incorporate the 4 busses into this new section... Add some more iron, maybe a buss compressor like the gssl 4000... Open for comment!

Any new thoughts on this?

1) A 2520 based fader booster.
2) What additional master section mods would be useful? I see adding the 2 channel ACA booster is common. How about balanced output transformers? Audio Maintenance used to offer a Carnhill transformer output kit. I'm not sure why the extra circuity is involved: https://www.gearslutz.com/board/product-alerts-older-than-2-months/413639-easy-carnhill-transformer-output.html
3) Any other areas of the console that could benefit from iron or balancing?
4) Perhaps adding 2 channel ACA boosters to the sub-groups?

 

[Eliani]

Any new thoughts on this?

1) A 2520 based fader booster.
2) What additional master section mods would be useful? I see adding the 2 channel ACA booster is common. How about balanced output transformers? Audio Maintenance used to offer a Carnhill transformer output kit. I'm not sure why the extra circuity is involved: https://www.gearslutz.com/board/product-alerts-older-than-2-months/413639-easy-carnhill-transformer-output.html
3) Any other areas of the console that could benefit from iron or balancing?
4) Perhaps adding 2 channel ACA boosters to the sub-groups?

The 2-aca-bo is not just a fader booster, but it provides a balanced out for insertion after a true API summing amplifier. Plus a balanced master output after the fader booster through the API output transformers.

I'm still thinking about that master section mod, like having a true monitoring control, better metering, adding different colour transformers to the groups.

 

[critterkllr]

The 2-aca-bo is not just a fader booster, but it provides a balanced out for insertion after a true API summing amplifier. Plus a balanced master output after the fader booster through the API output transformers.

I'm still thinking about that master section mod, like having a true monitoring control, better metering, adding different colour transformers to the groups.

Nice. I know I knew that at some point about the balanced outputs, but dumped it out of my brain for some reason.

Excited to hear some of your thoughts about the master section when you're ready. And sub-groups would be a big one for me. I always run my tracks through sub-groups to help make things easier and add buss effects/compressors.

 

[Eliani]

So after a long time, and a busy festival-season I opened up my Eagle once more and when it sprang to life it opened up the That 1512 preamp I was working on for the Tac scorpion...

Anyone still interested in this little project? I could cook up a batch if there are people interested...

 

[Eliani]

Take a look...

 

[bluezplaya]

Hahahaha wow you're busy designing all sorts of preamp mods for the Scorpion! So what sort of sound would this THAT1512 give a channel strip? I'm always interested in upgrades/mods for the TAC.

 

[Eliani]

Hahahaha wow you're busy designing all sorts of preamp mods for the Scorpion! So what sort of sound would this THAT1512 give a channel strip? I'm always interested in upgrades/mods for the TAC.

I remember the That chips to be ultra clean, so I guess you'll get just that! But as we speak I'm working on something far more important for the little Sorpion! Something to do with inductors!!