EZ Tube Mixer Support Thread

[Brian Roth]

The Mouser "each" price is less than the Ebay listing, but shipping costs (and custom fees??) may skew the total price.

Additional info:

https://daviesmolding.com/catalog/series/knobs/control/?SeriesID=1400
Bri

 

[matriachamplification]

The Mouser "each" price is less than the Ebay listing, but shipping costs (and custom fees??) may skew the total price.

Additional info:

https://daviesmolding.com/catalog/series/knobs/control/?SeriesID=1400
Bri

Thanks!

We found out Digikey will pay all custom fees. We have been working with them since and they carry Davies Moulding line.

What my wife is looking for is the smallest RCA Viz Mic Knobs used on Broadcast consoles. 1 inch diameter seems to be the smallest we can find.

Any suggestions.

 

[Brian Roth]

Now that I looked closer, the basic 1400 knob doesn't have the brass insert. This one does:

https://www.mouser.com/ProductDetail/Davies-Molding/1400-W?qs=LzMQyyTPAEeU6g9MyOSjCA==
Bri

 

[Brian Roth]

I recall those knobs being used by Ampex on the 350 and 351 audio electronics chassis units:

https://soundgas.com/wp-content/uploads/2020/11/Ampex-350-Two-Track-Tape-Machine-15-scaled.jpg
And I'm over thinking this...lol. Do keep in mind those 1400 series knobs are for 0.125" diameter shafts on the pot/switch.

EDIT: I meant to say 0.250" ..... 1/4" shafts

Bri

 

[ruffrecords]

I have just been through this entire thread and updated the pics and docs included in my posts because many of the links were broken. Most I have attached directly to the posts themselves so they are stored on the group server and should outlast me!

Cheers

Ian

 

[Tahoebrian5]

Is anyone else considering building an EZtubemixer anytime soon? I am planning to move ahead and wondering if anyone wants to collaborate for parts sourcing, pcb board orders, etc.

Also this project is a bit over my skill level so I’ve got some growing pains coming my way!

im combing my way through all the docs on Ian’s blog site and trying to decide exactly what I want to include.

im leaning towards just doing a 12 ch line in mixer and either leaving space in the frame for future pres, or just have a separate box for pres and I can use my 500 pres in the mean time.

 

[ruffrecords]

There is no doubt that, despite the name, an EZTubeMixer takes a lot of effort to build. It takes me 6 months to build a custom 6 channel one and I designed the thing. The beauty of a modular design is that you can part populate it so it can be useful long before it is complete. My advice to you would be to think long and hard about the features you want, then do the mechanical design (which includes working out where the hell all the wiring will go) before you start on the electronics. As always I am happy to lend support.

Cheers

Ian

 

[Tahoebrian5]

Thanks for the positive vibes Ian! Not to mention the countless amount of effort you have made available.

 

[Tahoebrian5]

well after some thought I am thinking about first building a 2 CH “channel strip” just to be able to run some audio through and get a feel before I go all in.

so 2 channels of the preamp with EQ

 

[ruffrecords]

well after some thought I am thinking about first building a 2 CH “channel strip” just to be able to run some audio through and get a feel before I go all in.

so 2 channels of the preamp with EQ

Excellent choice. You will learn a huge amount from doing this which will put you in a good position to tackle the remainder of the project. This is exactly what I am doing right now on the Poor Man's Tube Mixer project.

Cheers

Ian

 

[Stevie342000]

Building electronics is like making clothes....you have a pattern...you make up a sample...you refine the sample and then when you are happy you go on to your main garment or build...you learn more that way and iron out any issues before the main run.....

 

[Clakejr]

Can I use Telefunken tubes for the Twin Line Amp?

 

[ruffrecords]

Can I use Telefunken tubes for the Twin Line Amp?

As long as you use the correct type of tube, i.e 12AX7/ECC83 and 6922/E88CC then it does not matter who made them.

Cheers

Ian

 

[Jamie1234567]

Hi,

Many years ago I purchased the PCBs and some parts for this project with a view to building myself a tube mixer, but life got in the way and the project got shelved for longer than I care to admit. After looking shamefully at the box of bits sat on my shelf for several years, I’ve finally decided to try and do something about it!

Here’s what I’ve got:
6 x EZ Mixer Eurochannel V3 PCBs
6 x Helios EQ (version 1) with inductors and grayhill switches
4 x EZ Mixer Twin Line Amp V1
5 x backplane PCBs (with 2 connectors per card)
12 x Carnhill VTB2291 Transformers (more on this in a moment..)

At this point, I can’t even remember what my plan was for the mixer, but I’m not really needing a mixer any more. What would be a lot more use to me now would be if I can cobble together 6 mic preamps with EQ. Any suggestions on how to do this using the PCBs I have? Will I need some kind of make-up gain for the EQs? Or some sort of buffer for the outputs?

I have a reasonable amount of experience with DIY but haven’t done much with tubes (except a couple of guitar amp kits). Obviously I am aware of the electrocution risk etc, but I feel like I’m ready to take on this project now.

Also regarding the transformers. I clearly messed up at the time and bought the wrong ones. I’m not entirely sure how this happened but it was several years ago so there’s not much I can do about that now! I must have spent a lot of money on these at the time! The VTB2291 that I have is the ungapped version, and from what I understand I should have bought the VTB2290 (gapped) version. Can these still be used?

I realise there's going to be a lot of work (and a fair bit of money) involved in getting this finished, but I just can't bear to look at the PCBs sat on my shelf any longer!

Thanks!

Jamie

 

[ruffrecords]

The EZTubeMixer Eurochannel and Helios PCBs are designed to work together. The Eurochannel has a mic pre AND a gain make up amp for the passive EQ. So you feed signal into the mic and line inputs of the Eurochannel. You come out of OUT1 into the EQ. The from the output of the EQ back to the Fader in of the Eurochaanel which internally you connect to IN2 (which is the input of the make up gain amp) It output is OUT 2 which you then send to the output transformer.

The good news is you got the RIGHT transformers. You need the ungapped version.

I think somewhere I have the fpd file for a 6U high front panel for the Eurochannel and Helios EQ. So you could make 6 x 6U modules and fit them in a 6U sub-rack and power it from an external power supply.


Cheers

Ian

 

[Jamie1234567]

Ah ok that is seriously good news about the transformers - I'm not sure where I got the idea that I had the wrong ones but I must have got confused somewhere!

Thanks for the info. That's exactly what I'm hoping to do - 6 modules in a 6u sub rack with an external power supply. I found your fpd files for the Eurochannel with the Helios EQ and will use this for a starter (and modify it a bit as I won't be needing pan etc.).

Thanks for a great DIY project. I'm sure I will be back with many questions as I progress through it!

 

[ruffrecords]

There is a bunch of info under the DIY tab on my web site: Custom Tube Consoles - DIY

Just scroll down and click on the EZTubeMixer folder.

Cheers

Ian

 

[Jamie1234567]

Thanks Ian, I have read through a lot of your information now already - but there's a lot to take in!

I'm just trying to figure out which subrack I need for a 6u build (6 x channels with helios EQ). I think I will probably chance it with unshielded individual modules rather than trying to track down 6u fischer cassettes. I can always construct some sort of shielding between the individual modules as an afterthought if I am having problems.

Does this look like the right thing for the 6u subrack?
https://uk.farnell.com/schroff/24563-434/subrack-6u-355mm-84hp/dp/1455793
Thanks!

 

[ruffrecords]

That looks about right. It is definitely the backplane version which is what you need. It also looks deep enough - you need some space behind the back plane to mount the output transformers. You an either mount them on a rear panel with the connectors or you can mount them on the side panels, three on each side.

Whereabouts are you in the UK. I may have a spare 6U rack you can have for a lot less than the Farnell price.

Cheers

Ian

 

[Jamie1234567]

That looks about right. It is definitely the backplane version which is what you need. It also looks deep enough - you need some space behind the back plane to mount the output transformers. You an either mount them on a rear panel with the connectors or you can mount them on the side panels, three on each side.

Whereabouts are you in the UK. I may have a spare 6U rack you can have for a lot less than the Farnell price.

Cheers

Ian

Hi Ian,

I’m on the Isle of Wight, so not exactly convenient but if you were willing to post the rack I would gladly buy it off you. No problem if not though!