[Build] CAPI Summing Mixer ~ SumBus ACA ~ Official Support Thread

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jsteiger

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Hey folks

I am planning to turn the buy buttons on for the SumBus32 during this coming week. All things are in place except the final packaging. Due to the weight, I will be double boxing so the needed shipping supplies are holding me up. It won’t be long though! I will blast a note on social media when they go live so look me up if you haven’t already.

Details and automated checkout for the SumBus32 can be found here:
http://capi-gear.com/catalog/index.php?cPath=217_219

We are a ways out for the rotary controlled SB-1T version. I am thinking those will hit later in the year.

I have changed the way the support docs and build pics are presented. Instead of cluttering up this thread with a zillion pics, I have them posted at my site along with detailed instructions.

The build pictorial can be found here:
http://capi-gear.com/catalog/Build_SumBus.php

Since this is the official support thread, please post all questions, components and/or build problems here. I will do my best to help you get things sorted.

SumBus32 with SB-2T channels:
SumBus32-close.jpg


SumBus16 with SB-1T channels:
SumBus16-close.jpg


Cheers, Jeff
 

echoplex

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Hi Jeff,

they appear to be sold out. Any clue when you will have these bad boys available again?
Especially interested in a SumBus16 with SB-1T channels
 

Blackdawg

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echoplex said:
Hi Jeff,

they appear to be sold out. Any clue when you will have these bad boys available again?
Especially interested in a SumBus16 with SB-1T channels

They haven't gone on sale officially yet. However the SB1 won't be ready for sale till later this year. Only the SB2 will be available in the next week or so.


So stoked Jeff!

Monte
 

kante1603

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Awesome Jeff!


May I ask two (first?) questions:


1.:On the channel inputs,what impedance do we look into (as we want it on the high side -say 10k Ohms- for attaching our interface outputs nowadays)?


2.:For the psu,I see you use an SMPS followed by some heavy filtering.Is it also possible to run a full 32-4-unit from one of your floorboxes current wise?


Thank you in advance,


best regards,


Udo.
 

jsteiger

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kante1603 said:
1.:On the channel inputs,what impedance do we look into (as we want it on the high side -say 10k Ohms- for attaching our interface outputs nowadays)?
Hi Udo! The input Z is appx 10k ohms. Same as the VP28 in line mode.

2.:For the psu,I see you use an SMPS followed by some heavy filtering.Is it also possible to run a full 32-4-unit from one of your floorboxes current wise?
Indeed it is. One of the VPR outputs from the Floor Box will run a full 32x4 with no problem.
 

BramK

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I'm nearing the completion of my 16x2 SumBus build. For those of you who are currently building or are considering the project, I've created a picture album with pics and notes so you can get an idea of what it entails. For the record, Jeff's build guide is more than adequate to follow along for your average hobbyist DIYer - this is a massive project though, I would not recommend to those who don't already have plenty of experience building DIY preamp kits, etc..

Feel free to reach out if you have any questions!

CAPI SumBus ACA Build Photo Album
 

kante1603

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Awesome work Bram,congrats!
It was a pleasure to watch your pics (and reading your comments of course).


Best regards,


Udo.
 

echoplex

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BramK said:
Feel free to reach out if you have any questions!

CAPI SumBus ACA Build Photo Album

Impressive built and great work mate!
I have a question regarding the  garAM10 OpAmps you use.
Have you compared the  garAM10 to any 2520-style DOA like the Rouge Five or gar2520?
How do they differ in terms of sound and color?
 

BramK

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echoplex said:
Impressive built and great work mate!
I have a question regarding the  garAM10 OpAmps you use.
Have you compared the  garAM10 to any 2520-style DOA like the Rouge Five or gar2520?
How do they differ in terms of sound and color?

Thanks!

Once the build is complete I will do some shoot outs with the different op-amps I have (gar2520, gar1730, LTL Rogue Five, garAM10) on a full mix and post the files.

I did compare the AM10s with the 2520/1730 combo in a VP28. It was a quick test on a mono elec distorted guitar. At unity the differences were subtle, I would say that the AM10s are less mid-forward and not as aggressive. However, cranking the input wide open is where clear differences emerge. The 2520 gets crunchy and nasty (in a tasteful way) fast. The AM10 breaks up later and doesn’t obliterate the signal like the 2520, it was also less bright.

I also ran a mono acoustic drum loop through and preferred the 2520 over the AM10, it seemed to have more weight, punch, and brightness (but it’s easy to bias towards brighter things out of context).. In a full mix it might be a different situation.
 

Greenote

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Hi Jeff,
My build went relatively smoothly.

I have 6 working cards. Two of my sum cards appear to have problems with the switches. Hitting the a top Summ busA  button (switch) kills all the other Bus button LEDs on that strip. I have the same problem on another card but it happens on two buttons.
I did switch out the meter board to see but the meter cards appear to work on different cards.

I've looked over the sum card to ensure all the diodes are correctly polarized. All the transistors are going the right way.

Any thoughts?

Some Additional feedback.
Like most of your projects this is superbly thought out and well documented, however the LED's make for a very difficult mounting of the cards into the guide/faceplate. If you every rev this project it may be worth using a pre-designed meter strip or even using less LEDs on the metering side.

I wound up inserting the file into a drill, this definitely beat filing hundreds of holes by hand.

Thanks Todd
 

jsteiger

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Greenote said:
Hi Jeff,
My build went relatively smoothly.

I have 6 working cards. Two of my sum cards appear to have problems with the switches. Hitting the a top Summ busA  button (switch) kills all the other Bus button LEDs on that strip. I have the same problem on another card but it happens on two buttons.
I did switch out the meter board to see but the meter cards appear to work on different cards.

I've looked over the sum card to ensure all the diodes are correctly polarized. All the transistors are going the right way.

Any thoughts?
You've likely got some LED's in backwards.
 

Greenote

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Thank you for the quick reply.  LED orientation was the first thing I checked. They are correct and match the working boards. I removed one of the LED's and the corresponding switch still knocks out the other LED's when engaged.
I'll keep poking around.

Thanks TR
 

outraged

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This looks amazing! GREAT work as always. (To bad I'll never be able to afford it and already have a summing bus lol)
 

jsteiger

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outraged said:
This looks amazing! GREAT work as always. (To bad I'll never be able to afford it and already have a summing bus lol)
I was happy...and then sad. Thanks though!
 

XAXAU

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Are there any other cool transformers that fit this form factor?

Other than having different opamps on A and B I don’t see the point.

When are the  SB-1T coming out.

Also, I’d prefer 8 channels of SB-1T and have a monitor section on the right with meters, Elma volume and monitor controller.
 

Blackdawg

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XAXAU said:
Are there any other cool transformers that fit this form factor?

Other than having different opamps on A and B I don’t see the point.

When are the  SB-1T coming out.

Also, I’d prefer 8 channels of SB-1T and have a monitor section on the right with meters, Elma volume and monitor controller.

You can fit different output transformers and opamps on the B bus. Jeff offers 5 different transformers right now.

I still think 8ch of SB1 channels with 16-24ch or SB2 would be cool
 

critterkllr

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I'm considering building this soon. Can anybody point me in the direction of some audio samples? I'd love to hear some music summed itb compared to the CAPI Sumbus. If you have one, would you be willing to post or send me something? Thank you!
 

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