EZ Tube Mixer Support Thread

[matriachamplification]

Hello ITB Systems builders

Well I may as well layout the vision for our overall design of Mr. Thompson-Bells Classic EZTM.

Attached is a photo I imagine many to know well. Follie Audio are amongst Ethan Winers, Mr. Carlsons Lab and Mr. Thompson-Bell as gospel to our family in the audio world of education. When we first discovered this image some years ago we had begun the concept of a completely minimalist, path of least residence approach to professional audio and set out some basic rules.

1. We eliminated all commercially mass marketed/manufactured pro audio products as off limits. (not by choice, many told us to bleep right off, I will tell stories in our private Pateron page)
2. We could only work with analog designs we can repair without much worry.
3. Everything needed to be modular, modern and interesting.
4. It needed to be scalable in hands on training, meaning month to month new elements were to be introduced.
5. ELIMINATE CUSTOMER PORTALS AND PAPER WORK

And then in 2016/17 I found Mr. Thompson-Bells CTC homepage. For the next several years we worked around ITB designs given our existing partners were already established DIY designers and manufacturers and it was easy to learn from their builds.

To cut things short, it took some time to collectively grasp what Mr. Thompson-Bells overall designs were.

We mostly suffer, (or I mostly suffer) from remembering/understanding master section of mixer design.

None the less we are making a replica of this console with Mr. Thompson-Bells input on some details as well as your help with a few aspects.
Given the console will be larger then the 19"s needed for ITB systems, we are looking at modular or compact solutions for 4 channels of TUBE COMPRESSION to be integrated into this layout.

I like the AML-17-033 Magic Eye as the esoteric goto. However these will never fit.

Any thoughts?

Oh, I am also officially referring to Mr. Thompson-Bells overall designs as ITB Audio Systems. ITBAS.

Created a better image of the console for all to review.

More soon...

Wall

 

[ruffrecords]

The EZ Tube designs are based around standard Eurocards which are 100mm tall and 160mm deep. By the time you include the connectors and the overall supporting frame. each module needs about 200mm (8 inches) of depth behind the front panel. Thus, one serious problem with the console pic you posted is that its slope is so shallow and the front piece so short that the modules will be buried in the table top.

Cheers

Ian

 

[matriachamplification]

Here is a copy of a desk concept we started years ago build off shallow depth racks and markers on the repurposed 8 foot kitchen countertop.

All this gear was culled over the years to pay for therapy. The only item I am looking to replicate is the Culture Vulture.

Emerson Pringle is a friend and the carpenter that was building this design with me a decade ago.

Today Mr. Pringle has once again joined the goal and is designing out the EZTM mixer enclosure with  dovetail joints to start.
https://emersonpringle.com/

Emerson is a live audio engineer and former studio owner/designer so the conversations are almost non existence.

 

[matriachamplification]

We are curious if we can utilize the TLA2 card retooling it as a Tube Harmonic Distortion Overdrive Module.

Given NFB is used via the 47K resistor to cull the distortion can this be modified to promote distortion as opposed to eliminate it?

"An SRPP provides lots of drive capability but its distortion is rather high. Negative feedback is applied via the 47K resistor Rfb
to the cathode of the 12AX7WA to stabilize the gain and reduce distortion." Ian Thompson-Bell
http://www.customtubeconsoles.com

 

[ruffrecords]

We are curious if we can utilize the TLA2 card retooling it as a Tube Harmonic Distortion Overdrive Module.

I would not recommend it because there are better  and simpler ways of achieving tube overdrive. I would not endorse it because the TLA is designed as a relatively clean amplifier.

If you want tube overdrive distortion then just use a single SRPP stage on its own. Just using the 6922 biased as it is in the TLA will give you the effect you want.

I have spent the last ten years striving to design and build clean pro audio tube preamps and mixers. Yet all the time I am asked to design/build a tube distortion box - its depressing.  A clean class A tube design shines in comparison to almost any semiconductor design; the sound is incredible.

Cheers

Ian

 

[matriachamplification]

I would not recommend it because there are better  and simpler ways of achieving tube overdrive. I would not endorse it because the TLA is designed as a relatively clean amplifier.

If you want tube overdrive distortion then just use a single SRPP stage on its own. Just using the 6922 biased as it is in the TLA will give you the effect you want.

I have spent the last ten years striving to design and build clean pro audio tube preamps and mixers. Yet all the time I am asked to design/build a tube distortion box - its depressing.  A clean class A tube design shines in comparison to almost any semiconductor design; the sound is incredible.

Cheers

Ian

Thank you and our apologize for the depressing query. I work with 3D audio and for games, more often then not, I use Tube distortion to layer brittle or harsh undertones. I am uncertain how most use distortion outside of pedal effects, but this is critical to my workflow.

addition: My wife says, with all due respect Mr. Thompson Bell, the other options we are looking a add up to $4000. She finds that very depressing

 

[matriachamplification]

After my wife hired a "professional" 3D modeler my son and I tried our hands at Sketchup.

These components were sourced for free from Sketchup 3D Warehouse, with the layout being Mr. Thompson-Bell EZTM Classic Design!
The Black on Black VU meters was my sons choice and are available from a  Vu manufacturer in the UK.

What makes this design especially interesting is we are molding it off of the API 1608 Desk, adding more depth to compensate for the sub-racks and harness. This is to showcase Emersons carpentry to potential 500 Series Desk admirers.

We have almost completed the EuroChannel Card with casing to add to the model.

First time working in 3D very cool! The visual educational elements are exceptionally inspiring.

...more soon...

Wall

 

[matriachamplification]

And here is a side profile

 

[ruffrecords]

Thank you and our apologize for the depressing query. I work with 3D audio and for games, more often then not, I use Tube distortion to layer brittle or harsh undertones. I am uncertain how most use distortion outside of pedal effects, but this is critical to my workflow.

addition: My wife says, with all due respect Mr. Thompson Bell, the other options we are looking a add up to $4000. She finds that very depressing

If you really want tube 'colour' in an EZTubeMixer format then your best bet is to consider the old Classic Mic Pre V3 design. This is a simple two tube design based on the old fixed gain stages interspersed with variable pads that was the hallmark of the old RCA tube broadcast mixers.. They use a mu follower topology for lower distortion but if you do drive them hard they will produce 'colour' because they have no negative feedback. If you want more colour, a few simple component changes will convert the two stages into SRPPs which will produce even more colour but slightly less gain. As I said this board as originally designed is EZTubeMixer compatible but the popularity of the design very soon morphed it into a stand alone DIY mic pre with built in power supply. Many people in this group have built them as fairly clean stand alone mic pres and many have built them as relatively dirty DI boxes. I do not have any of the EZTube versions of this board in stock any more but if you want some I am happy to have some made.

Cheers

Ian

 

[matriachamplification]

Lets hold off on any additional Cards outside of what I need listed below.


Where I am at is attempting to devise a simple analog monitor controller for the basic 5.2.2 Dolby Atmos setup utilizing the TLA2 cards.
That said we are going to run a "full house" with 6 Channel Strips paired off into each EQ; Pultec, Helios and REDD.

The addition of a 2 slot Mother Board would be needed. However, would it be best to look at a 4 slot mother board to give more flexiblity to the monitoring section.

I seem to be overthinking. May a standalone "Mastering" meter bridge and monitor controller for this make more sense for this approach with the TLA2 cards?

 

[matriachamplification]

https://canada.newark.com/schroff/24563-194/19-inch-subrack-europacpro-kit/dp/59M5130

We are about to order this subrack and want to make sure this is the proper dimensions.

 

[ruffrecords]

https://canada.newark.com/schroff/24563-194/19-inch-subrack-europacpro-kit/dp/59M5130

We are about to order this subrack and want to make sure this is the proper dimensions.

According to the data sheet this one is intended for individual rear connectors but if you are using the EZTubeMixer motherboard you need the type that takes a motherboard. Apart from that it looks OK.

Cheers

Ian

 

[ruffrecords]

I think this is the one you need:

https://canada.newark.com/schroff/24563-134/19-inch-subrack-europacpro-kit/dp/59M5125?ost=24563-134&ddkey=https%3Aen-CA%2FElement14_Canada%2Fsearch

Cheers

Ian

 

[matriachamplification]

I think this is the one you need:

https://canada.newark.com/schroff/24563-134/19-inch-subrack-europacpro-kit/dp/59M5125?ost=24563-134&ddkey=https%3Aen-CA%2FElement14_Canada%2Fsearch

Cheers

Ian

Thanks!

 

[matriachamplification]

After one week of actually working on the build my son is eagerly on board and adding his own ideas to the projects design.

My son asked
"if the eq can be swapped plug and play, can we add dual eq's to each mic pre with a switch to select the REDD or Helios eq?"

He thought of this idea for a voice over set up where he could have optional eq's for different voice actors without spending time swapping.

I cannot see why this would not work but am asking prior to putting into action my thoughts are mainly on the layout of the eq's face plating to fit 12 eq channels into a 6 channel space.

We are already building the eq's, makes sense. Thoughts?

 

[ruffrecords]

There is no reason in principle why this cannot be done. It is just a matter arranging the switching. As you correctly surmise, the challenge is going to be fitting all those controls on one front panel whilst retaining good ergonomics.

Cheers

Ian

 

[matriachamplification]

There is no reason in principle why this cannot be done. It is just a matter arranging the switching. As you correctly surmise, the challenge is going to be fitting all those controls on one front panel whilst retaining good ergonomics.

Cheers

Ian

we are adding a rack space to 7u for the dual eq layout.  this way we can stager the controls .  i will need to order eq boards from you soon.

 

[ruffrecords]

we are adding a rack space to 7u for the dual eq layout.  this way we can stager the controls .  i will need to order eq boards from you soon.

Staggering is the way to go but I suspect it will be "fun" to wire up all those controls.

be aware that many Chinese PCB manufacturers have been temporarily shut down or at least slowed down  by lack of staff due to the Corona virus outbreak so if I need to order any extras they may be a delay.

Cheers

ian

 

[matriachamplification]

Staggering is the way to go but I suspect it will be "fun" to wire up all those controls.

be aware that many Chinese PCB manufacturers have been temporarily shut down or at least slowed down  by lack of staff due to the Corona virus outbreak so if I need to order any extras they may be a delay.

Cheers

ian

Noted about pcb orders delays

maybe a good opportunity to solidify what PCBs i need, open source included, and  order them all through you, if thats okay?

Channel Strips
12 x REDDEQ
12 x Helios69V2
24 x ?CTCPhantom?
8 x Eurochannel
1 x Motherboard V6
?  x Grayhill Header?
1 x CTCHT450


Master/Monitor Sections TBD

 

[ruffrecords]

Noted about pcb orders delays

maybe a good opportunity to solidify what PCBs i need, open source included, and  order them all through you, if thats okay?

Channel Strips
12 x REDDEQ
12 x Helios69V2
24 x ?CTCPhantom?
8 x Eurochannel
1 x Motherboard V6
?  x Grayhill Header?
1 x CTCHT450


Master/Monitor Sections TBD

One reason for open sourcing PCBs is so I no longer need to make and stock them. I thought Dylan was doing this for you for the open sourced ones.

I am happy to supply you with the remainder i.e. REDDEQ, EUROCHANNEL, MOTHERBOARDV6. Just give me the nod when you want them.

You should only need one phantom PCB per mixer (one board is capable of supplying up to 100mA at 48V)

Not sure why you need the Grayhill header but they went out of stock a long time ago. They were a one off Black Market thing. I suspect you might be thinking of using it for the REDDEQ mid frequency select switch. Just about everyone who built REDDEQs  (including me) used a cheaper Lorlin 2 pole 6 way switch and hard wired it to the PCB.

HT450 is open sourced but I am moving away from fully home built HT supplies. For most EZTubeMixer projects you can use an off the shelf 250V 100mA power supply made by International Power:

https://www.mouser.co.uk/ProductDetail/International-Power/IHB250-01?qs=0xCm9DOQnC5apaiylMDitA%3D%3D

Cheers

Ian