EZ Tube Mixer
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KMB-AUDIO
Well-known member
Ian,
What is the pin spacings for the options you have on the board now? From the cinemag data sheet (http://cinemag.biz/line_input/PDF/CMLI-15-15B.pdf), it looks like the pin spacing is 5.08 mm. The jensen is a bit narrower at 3.81 mm (http://www.jensen-transformers.com/datashts/11p1hpc.pdf).
What is the pin spacings for the options you have on the board now? From the cinemag data sheet (http://cinemag.biz/line_input/PDF/CMLI-15-15B.pdf), it looks like the pin spacing is 5.08 mm. The jensen is a bit narrower at 3.81 mm (http://www.jensen-transformers.com/datashts/11p1hpc.pdf).
ruffrecords
Well-known member
KMB-AUDIO said:
For the mic pure I made a single foot print that combined the pins of the Sowter, Jensen and Cinemag mic transformers. I used this same footprint for the twinlineamp. Looking at line input transformer data sheets I find it is only the Sowter that has the same pin spacing.
Cheers
Ian
Edit: I have just phoned my PCB manufacturer to stop its production while we fix this. With luck they will not have started on it yet.
ruffrecords
Well-known member
anjing said:
Well done, it worked. They have stopped it at zero cost to me.
Cheers
Ian
ruffrecords
Well-known member
@Pierre
This may not be as bad as it seems. As far as I can make out, all the following transformers have an identical pin out/spacing:
CMMI-10-PCA the original Cinemag mic input transformer
CMLI-15/15PCA a Cinemag line in transformer
JT-11P1-HPC a Jensen line in transformer.
So it seems the only one that won't fit it the Cinemag CMLI-15/15B[PCA]
which means if you use the compatible Cinemag we do not need to change anything.
Cheers
Ian
This may not be as bad as it seems. As far as I can make out, all the following transformers have an identical pin out/spacing:
CMMI-10-PCA the original Cinemag mic input transformer
CMLI-15/15PCA a Cinemag line in transformer
JT-11P1-HPC a Jensen line in transformer.
So it seems the only one that won't fit it the Cinemag CMLI-15/15B[PCA]
which means if you use the compatible Cinemag we do not need to change anything.
Cheers
Ian
ruffrecords
Well-known member
Pierre, looking back at my last post I realize there are two versions of the Cinemag PCB mounting input transformer with different footprints. The larger (which you have) takes inputs up to +20dBu and the smaller up to +18dBu. That and the size of the footprint seems to be the only difference between them. The silly thing is there is only a single letter 'B' difference in the part numbers. So, as the smaller one fits in the Cinemag mic transformer footprint I propose we standardise on that one - the one without the 'B'. This means the PCB layout is correct and I can get them made.
Cheers
Ian
Cheers
Ian
KMB-AUDIO
Well-known member
In real world practice, is the difference between +18dBu and +20dBu substantial? I looked up the specs for my converters and they have a max output of +22dBu; I imagine that I would have to get pretty close to "digital zero" to hit that.
I'm with you Ian, keep it as is unless there would be a huge benefit to include the footprint for the larger transformer.
I'm with you Ian, keep it as is unless there would be a huge benefit to include the footprint for the larger transformer.
ruffrecords
Well-known member
KMB-AUDIO said:
Yes, your converters would have to output almost exactly digital zero to hit that. The other thing to remember is that the spec of +18dBu is for 1% distortion at 20Hz. How often will you have that high a level at 20Hz? And as you go up in frequency the distortion drops and the maximum level increases. CJ would be the best person to elaborate on that topic. And of course most people set 0VU to be -15 or -18dB below digital zero leaving a good margin for occasional peaks.
So overall, I think the extra couple of dB makes no noticeable difference for normal program material
@Ian
Good then, i will find a way to use my transformers anyhow, i'll just be more carefull on my next order. I haven't contacted Dave yet. I have been busy soldering, soldering and soldering!
Sorry for the trouble and thanks!
Pierre
Good then, i will find a way to use my transformers anyhow, i'll just be more carefull on my next order. I haven't contacted Dave yet. I have been busy soldering, soldering and soldering!
Sorry for the trouble and thanks!
Pierre
ruffrecords
Well-known member
anjing said:
OK, Pierre I will re-start the PCB order.
For using the bigger transformer, perhaps you you use my old method of turning it upside down and glueing it to the PCB then use short leads from the transformer pins to the PCB pads.
Cheers
Ian
ruffrecords
Well-known member
I have been thinking about the end profile of and fitting wooden sides and front buffers to the EZTubeMixer. The idea is to give the mixer a professional appearance without requiring exceptional mechanical expertise (so it is ideal for me!!). I spent some time trying various schemes and my favourite is is this one:
This is looking at the mixer end on. To the right you can see the nose where the faders would go. Above them is a 9U space for the main electronics. You can divide this into a 6+3, or a 3+6, or a 3+3+3. At the bottom left (the rear of the mixer) is another 3U space for extra line amps, transformers etc. Above this a 3U high panel space for mounting XLRs. The holes marked 'W' are for screws to hold the wooden side on.
I drew this in front panel designer and the one of price comes out at about 125 Euros.
Cheers
Ian
This is looking at the mixer end on. To the right you can see the nose where the faders would go. Above them is a 9U space for the main electronics. You can divide this into a 6+3, or a 3+6, or a 3+3+3. At the bottom left (the rear of the mixer) is another 3U space for extra line amps, transformers etc. Above this a 3U high panel space for mounting XLRs. The holes marked 'W' are for screws to hold the wooden side on.
I drew this in front panel designer and the one of price comes out at about 125 Euros.
Cheers
Ian
Nice one, Ian, more or less the direction I want to go. But I haven't found the time to design it.
IIRC Frank Röllen has a new CNC machine, he could probably make these panels.
IIRC Frank Röllen has a new CNC machine, he could probably make these panels.
ruffrecords
Well-known member
@Pierre, Holger
Yes, the idea is these replace the Schroff side cheeks. All you need to buy then is the various extruded rails. The cheeks are 3 mm thick so you can countersink the screws and butt them together. I thought of adding some tapped holes to make it easy to bolt them together.
I am thinking of using one inch wood for the cladding. The shape of the wood would be the same as the metal but extend downwards one extra inch and mate with an inch thick rectangular sheet that forms the bottom of the mixer. There would also be a wooden rear panel above the XLRs and the woden cheek would also extend an inch at the top to mate with a wooden top piece and similarly extend and inch in front of the fader section to mate with an arm rest.
Frank told me about his new machine. I think it could do this job but I have not asked him yet.
Cheers
Ian
Yes, the idea is these replace the Schroff side cheeks. All you need to buy then is the various extruded rails. The cheeks are 3 mm thick so you can countersink the screws and butt them together. I thought of adding some tapped holes to make it easy to bolt them together.
I am thinking of using one inch wood for the cladding. The shape of the wood would be the same as the metal but extend downwards one extra inch and mate with an inch thick rectangular sheet that forms the bottom of the mixer. There would also be a wooden rear panel above the XLRs and the woden cheek would also extend an inch at the top to mate with a wooden top piece and similarly extend and inch in front of the fader section to mate with an arm rest.
Frank told me about his new machine. I think it could do this job but I have not asked him yet.
Cheers
Ian
KMB-AUDIO
Well-known member
This is pretty much what I was going to do as well! I've been working up a design with my channels coming in at 2" wide, I have big fingers and need the room 
I'm going to wait on the final design once I get the EQ boards from you to see if my design will work ok.
@Ian, are the Helios boards 3U now? Are these the ones you sent me? I ask because from the front panel designs I've seen here, the EQ boards seem to be taller than 3U.
I was going to work with http://www.8020.net/ to purchase the extruded rails.
I'm going to wait on the final design once I get the EQ boards from you to see if my design will work ok.
@Ian, are the Helios boards 3U now? Are these the ones you sent me? I ask because from the front panel designs I've seen here, the EQ boards seem to be taller than 3U.
I was going to work with http://www.8020.net/ to purchase the extruded rails.
ruffrecords
Well-known member
KMB-AUDIO said:This is pretty much what I was going to do as well! I've been working up a design with my channels coming in at 2" wide, I have big fingers and need the room
I'm going to wait on the final design once I get the EQ boards from you to see if my design will work ok.
@Ian, are the Helios boards 3U now? Are these the ones you sent me? I ask because from the front panel designs I've seen here, the EQ boards seem to be taller than 3U.
I was going to work with http://www.8020.net/ to purchase the extruded rails.
There are now two versions of the Helios EQ PCB. The original one is designed to fit into a 6U module along with the mic pre. It is nearly five inches tall which allows the three rotary switches to be spaced out quite nicely. It is too tall to fit into a 3U module. I think these are the ones I sent you. I have now made a 3U version that does fit into a 3U high module but because the board is now less than 4 inches tall the rotary switches are quite a bit closer together.
With your big fingers I guess the taller board would be better.
I think your channels need to be wider than 2 inches. The standard channel width we are using right now is 2.4 inches - much less and the tubes will not fit - so it should be OK for your fingers!!
Cheers
Ian
KMB-AUDIO
Well-known member
I would prefer the taller EQ, so that is good.
When I say channel, I mean fader, EQ, Aux/Pan. I plan on having the twin line amp in a separate bucket from the rest of the controls, so I don't think they need to match up, or am I not thinking about it the right way? Right now my two channel width is 4" as opposed to 2.4" as you have it - does that make any sense?
Another question, since I am not going to be installing any mic-pres, can I use the +48 rail on the backplane as a solo bus?
When I say channel, I mean fader, EQ, Aux/Pan. I plan on having the twin line amp in a separate bucket from the rest of the controls, so I don't think they need to match up, or am I not thinking about it the right way? Right now my two channel width is 4" as opposed to 2.4" as you have it - does that make any sense?
Another question, since I am not going to be installing any mic-pres, can I use the +48 rail on the backplane as a solo bus?
ruffrecords
Well-known member
KMB-AUDIO said:
OK, I forgot you were going to be using the twin line amp boards. In that case, yes, you can make your controls panel any width you like.
And yes, you can use the 48V as a solo bus since you have no need of phantom power.
Cheers
Ian
@Ian - I'm really diggin your design! We are doing something similar as well except ours is divided into mic pre/EQ (6U)
and FET compressor (4U) sections with meter bridge and fader bucket sections as well. Would you be willing to share your fpd file of the side piece design you made?
@KMB-AUDIO - Do you know what you're buying from 8020.net? Is there a certain part#? I ask as I've been on their site before and didn't necessarily find something off the shelf that had all the tapped holes. I can say that I didn't extensively look tho.
Thanks gentlemen,
Dave
and FET compressor (4U) sections with meter bridge and fader bucket sections as well. Would you be willing to share your fpd file of the side piece design you made?
@KMB-AUDIO - Do you know what you're buying from 8020.net? Is there a certain part#? I ask as I've been on their site before and didn't necessarily find something off the shelf that had all the tapped holes. I can say that I didn't extensively look tho.
Thanks gentlemen,
Dave
