pvision

Re: All Tube Sidecar
« Reply #40 on: January 26, 2018, 07:12:05 PM »
I had lots of ideas.

1 - Recording
If the console is used for recording then likely you'd use each channel direct output straight to the DAW and setup a monitor mix & headphone mix at the DAW via the audio interface. In that case the stereo outs of the console are not used and the direct outs could be post-fader

If you wanted to mix mics you could use the console stereo bus and patch that to the DAW as above

In this mode I doubt you'd need effects sends

2 - Mixing / Summing
In this mode you might need effects sends but I can't see a need for them to be pre-fader. If you need a pre-fader send then you could use the direct out - but setup #1 suggests the DO would likely be post-fader

Rather than provide effects sends I'd provide additional buses. Four buses could be two stereos or one stereo and two mono sends. For a mono channel you could have a send pot plus a 1, 1+2, 2, 3, 3+4, 4 switch to select which bus it feeds

This then suggests you could have two channel outputs, fader & small fader, each with a routing switch as above. This would give LCR panning without a panpot. Add panpots to complicate as required

Add a global pre / post switch to each routing switch and you'd have two stereo bus outs per channel fed from two faders (or pots) each switchable pre / post fader

That would enable a monitor mix and a main output mix

I'll do a diagram to explain...

Nick Froome

« Last Edit: January 27, 2018, 07:39:20 AM by pvision »


ruffrecords

Re: All Tube Sidecar
« Reply #41 on: January 27, 2018, 03:58:50 AM »
I'll do a diagram to explain...

Nick Froome

Diagrams are always good!

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

pvision

Re: All Tube Sidecar
« Reply #42 on: January 27, 2018, 07:36:26 AM »
Diagram attached

pvision

Re: All Tube Sidecar
« Reply #43 on: January 27, 2018, 08:08:16 AM »
This is the XML file for the diagram so anyone can edit it. To do so you'll have to remove the .pdf extension and rename it to .xml

It was created at www.draw.io

Nick Froome

ruffrecords

Re: All Tube Sidecar
« Reply #44 on: January 27, 2018, 10:46:50 AM »
HI Nick,

First question, why would you have the direct out after the fader?

Cheers

iam
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

pvision

Re: All Tube Sidecar
« Reply #45 on: January 27, 2018, 11:12:22 AM »
why would you have the direct out after the fader?
So you can ride levels while recording

It's tied in with the question "Faders or pots?" If you have faders - and we all like faders - then logically you should be able to use them while recording

There is a permanent pre-fader output at the insert send

Nick Froome

pvision

Re: All Tube Sidecar
« Reply #46 on: January 27, 2018, 05:20:47 PM »
Pan schematic

ruffrecords

Re: All Tube Sidecar
« Reply #47 on: January 27, 2018, 05:34:20 PM »
So you can ride levels while recording
OK. Is that common these days?

For a tube mixer this presents an extra difficulty; the fader needs to  be buffered. Its just another op amp in a semiconductor mixer but its an extra triode or two in a tube mixer. There would already be two or three triodes in the mic pre and the same in the EQ. The signal flow in my tube mixers is usually:

mic pre -> fader -> EQ -> EQ gain make up -> direct out

so you can still ride the faders.

You can add an optional unbalanced insert between the mic pre and the fader

Would you expect inserts to be balanced or unbalanced?

Cheers

Ian

www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: All Tube Sidecar
« Reply #48 on: January 28, 2018, 03:26:37 PM »
Direct outs are post fader on cheaper desks, on more expensive units you can switch it pre or post and it has a sperate control Pot. Again balanced inserts is all about price point, presumably that would be a lot of transformers for not a huge impact on sound,  but some folks insist on it

I would say a switch to shift the insert between pre and post eq is a great boon if you're going to go to that much detail.

ruffrecords

Re: All Tube Sidecar
« Reply #49 on: January 28, 2018, 03:36:55 PM »
Direct outs are post fader on cheaper desks, on more expensive units you can switch it pre or post and it has a separate control Pot. Again balanced inserts is all about price point, presumably that would be a lot of transformers for not a huge impact on sound,  but some folks insist on it

I would say a switch to shift the insert between pre and post eq is a great boon if you're going to go to that much detail.

Some people seem to want it pre-fader so you can use the faders for a monitor mix, others want it post fade so you can ride the faders during tracking. In some ways it may be easier to leave the direct out where it is and switch the fader either before or after it.

Back in the very early days, mixers consisted of individual units, all balanced in/out, that you could plug together any way you wanted. Then along came the 'integrated' mixers that did away with all the interstage balancing and provided a fixed set of facilities. Nowadays, people seem to want an integrated mixer that has a bunch of switches that let you reconfigure its internal modules in several ways. How long before we come full circle??

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


Re: All Tube Sidecar
« Reply #50 on: January 28, 2018, 05:17:21 PM »
Ha! That's true. The thing is, we've all got very used to doing whatever we want.

Personally I'd give up all of that stuff for something that sounded excellent, otherwise it starts becoming like a 90s large format mixer like a soundcraft TS12 or Midas heritage 3000 live console which is probably the most routable console ever, where you can do just about anything but all done with handy cheap 5534s.

A tube console is a different proposition

Re: All Tube Sidecar
« Reply #51 on: January 28, 2018, 05:35:17 PM »
---Deleted ---

didn't mean to sidetrack the discussion
« Last Edit: January 30, 2018, 08:49:36 AM by Timjag »

G-Sun

Re: All Tube Sidecar
« Reply #52 on: January 30, 2018, 03:23:00 AM »
Personally, the only thing I'd use a fader for is tone -pushing prior stage less/more.
A  0/-10/-20 pad would be all I needed.
And then, only if it made a difference in tone.

I agree with Timjag, a Tube console should focus on basic excellence.
After that sonic flexibility, like saturation or a different transformer-option etc.
Then routing, auxes and the like.

SS mixers seems just so much better for do-it-all-routing, and even then,
who wants a SS 50ch monster these days?

That said, I'm no tube-purist, and see big benefits in some IC rails present :)

Mind you, I'm a home-studio user,
and speak from these perspectives.
« Last Edit: January 30, 2018, 03:31:06 AM by G-Sun »
HJFP2, ssl9k, Harrison Ford Filters
My music

bluebird

Re: All Tube Sidecar
« Reply #53 on: January 30, 2018, 08:33:43 PM »
The market for a product like this is most likely going to be small studios or small mixing rooms. 90% of people will have pro tools/daw converters. I think you should put a good amount of work into the monitor section so people can throw out whatever they are using for a monitor box, Mackie big knob, Presonus monitor box, whatever.

Do your 8 tube channels simple like you first purposed. People will have 8 great tube recording channels and some cool eq's to mix selected tracks through.

The monitor section would be based around a nice Elma 4 deck 10K stepped pot. That way you could route auxiliary inputs directly to the pot and then to the monitor outputs. So a fully balanced monitor controller even when the whole console was not in use. Perhaps you could have a standby mode where the tube electronics were off but just the relay power would be on so the monitor section could be used without heating the whole room.

The Colman audio M3PHMKIII monitor controller uses a 4 deck Elma and is mainly passive with a headphone amp being the only active part. Simple mechanical push buttons for selection.
http://www.colemanaudio.com/cntrl.htm


So the monitor section would have:
Buss for the tube channels
Stereo monitor out with a selection for speaker set A or B.
Headphone out.
2 or 3 stereo auxiliary inputs for CD player or DAW main out, computer internal soundcard etc.

And if you want to go the extra mile...

16 channels via dsub connector of passive summing. You could feed it directly to the summing stage for the 8 tube channels. Or have a separate summing amp with a stereo output that could just be fed into two of the 8 tube channels. The only difficult (expensive) part is again the input transformers for unbalancing.

My 2 cents....




ruffrecords

Re: All Tube Sidecar
« Reply #54 on: January 31, 2018, 03:34:48 AM »
@Bluebird

I like your sensible uncluttered reasoning.

I had not mentioned the monitor system simply because, for me, that is the relatively easy part. I would base it on the way we did them at Neve - a couple of 10K:600 transformers with the inputs switched to select almost any balanced source you like. The 600 side would go to a 4 bank ELMA 600 ohm stepped level control. There are four reasons for doing it this way. First the monitor becomes a light 10K bridging load so it does not affect the level of the signals being monitored, Secondly it is galvanically isolated so there is no danger of creating a hum loop.he nominal. Thirdly, the +4dBu output is dropped to about -8dBu. This level is ideal for powered monitors and regular power amps alike. Fourthlyy, the monitor output is 600 ohms which is less likely to lose any HF or pick up any interference on its way to the power amp.

At Neve we typically started the monitor section with a big three position rotary switch with a Marconi knob  to select master bus, 2 track playback or other inputs. This allowed rapid switching between source and recording and in the third position levels could be set up and individual sources heard. The two track playback selection often had another switch to select several sources and the master bus position often had another switches if there were groups as well as the master stereo bus. The third postilion usually had further switches to select direct outs, AUX sends and so on. Often this was implemented as a bank of interlocking push buttons.

8 or 16 channels of dsub passive summing is already on the cards. If it is straight passive summing with no trim controls, pan or AUX sends then you don't need the transformers (just the two on the summing amp inputs).

You mentioned cool EQ. For a while now I have been trying to tie down a neat three band EQ. The problem has been that none of my EQs so far manages to have bass boost and cut on a single pole 12 way rotary switch. They all need two pole switches which limits you to a small number of manufacturers. Mid and High are no problem but bass always has been. However, my new mastering EQ design overcomes this - all bands are implemented in the same way and use only a single pole switch for  boost/cut. On another thread here I came across NKK MRK switches which are tiny single pole 12 way switches that are not too expensive. Using thee I have designed a simple 3 band EQ, loosely based on my REDD EQ design. Each band has three frequencies selected by a three position toggle. It all fits neatly into a 3U high 35mm wide module. I got the PCBs back the other day s I will be building and testing it in the coming weeks.

Once again, many thanks for your input.

Cheers
Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruairioflaherty

Re: All Tube Sidecar
« Reply #55 on: February 01, 2018, 11:23:46 PM »
I had not mentioned the monitor system simply because, for me, that is the relatively easy part. I would base it on the way we did them at Neve - a couple of 10K:600 transformers with the inputs switched to select almost any balanced source you like. The 600 side would go to a 4 bank ELMA 600 ohm stepped level control. There are four reasons for doing it this way. First the monitor becomes a light 10K bridging load so it does not affect the level of the signals being monitored, Secondly it is galvanically isolated so there is no danger of creating a hum loop.he nominal. Thirdly, the +4dBu output is dropped to about -8dBu. This level is ideal for powered monitors and regular power amps alike. Fourthlyy, the monitor output is 600 ohms which is less likely to lose any HF or pick up any interference on its way to the power amp.

Hey Ian,

Before I offer any input let me say that I am not the target audience for this console, my tracking & mixing days are in the past.  That said a transformer in the monitor path is an instant deal breaker for me in any pro audio application.

In my work setting up high end speaker systems I've had the opportunity to set up large ($50 to $100k) speaker systems in several Neve rooms with transformers in the monitor path.  I have a standard procedure where I always start listening from a Prism Sound DAC and then after some time route through the console monitor path.  The difference is often astounding and while it can be a fun sound, it's not what the source actually sounds like....

I've never heard a transformer that I would want in a monitor path, a WE111C gets close but even then it does change things subtly, and those changes mean different engineering choices based on flawed information.

An opamp buffered attenuator is the way to go here, I know it doesn't fit the retro aesthetic but it is the right tool for the job. The last one I built from a kit measured 0.0004% THD+N, hard to beat that.

 

ruffrecords

Re: All Tube Sidecar
« Reply #56 on: February 02, 2018, 04:01:56 AM »

I've never heard a transformer that I would want in a monitor path, a WE111C gets close but even then it does change things subtly, and those changes mean different engineering choices based on flawed information.

An opamp buffered attenuator is the way to go here, I know it doesn't fit the retro aesthetic but it is the right tool for the job. The last one I built from a kit measured 0.0004% THD+N, hard to beat that.

 

I agree that a transformer in the monitoring path inevitably colours the sound and that is the last thing you want in the monitor path (but I do wonder if it is significant in comparison the the colouration added by the monitor amp and speaker). Op amps are fine in this respect but unfortunately they do not provide galvanic isolation so tiny changes in noise/hum can and will take place and I think these are as important as colouration. In short, neither method is perfect.

The answer is probably to use a 10K balanced stepped pot for the monitor level and dispense with the transformer or op amp. In other words make it 100% passive. The downside with this approach is the output impedance can be as high as 2500 ohms which means that cable capacitance to the monitor amp can be an issue. For little or no phase shift at 2)Hz you want the 3dB down point to be about 10 times this frequency which gives a maximum cable capacitance of a little over 300pF. Using 40pF/metre cable means you can have over 7 metres of cable before you get that much capacitance

Thanks Ruairi, you just knocked couple of hundred bucks of the price of the mixer and improved its performance!

Cheers

Ian.
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

L´Andratté

Re: All Tube Sidecar
« Reply #57 on: February 02, 2018, 05:19:52 AM »
The answer is probably to use a 10K balanced stepped pot for the monitor level and dispense with the transformer or op amp. In other words make it 100% passive. The downside with this approach is the output impedance can be as high as 2500 ohms which means that cable capacitance to the monitor amp can be an issue. For little or no phase shift at 2)Hz you want the 3dB down point to be about 10 times this frequency which gives a maximum cable capacitance of a little over 300pF. Using 40pF/metre cable means you can have over 7 metres of cable before you get that much capacitance

Hi!
I take it you mean 20kHz, great explanation, thanks!
"Why not get an assistant to work the faders? Real vintage! And maybe cheaper... ;)"

ruffrecords

Re: All Tube Sidecar
« Reply #58 on: February 02, 2018, 06:46:54 AM »
Hi!
I take it you mean 20kHz, great explanation, thanks!

Yes, sorry for the typo - my brain continues to outpace my fingers.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: All Tube Sidecar
« Reply #59 on: February 02, 2018, 10:22:12 AM »
Hehe, Yeah with transformers in the monitor path you might end up making a terrible sounding album like Rubber Soul or Kind of Blue

 ;) :D