EZ Tube Mixer Support Thread

[Holger]

I've recently received 1000mm rails from Fischer, here is a first photo

 

[anjing]

Holger could i bother you for the part numbers of the front and rear rails?

Regards,

Pierre

 

[ruffrecords]

We have to think of a name for Holger's monster lunchbox. How about the Picnic Basket or the Party 14?

Cheers

Ian

 

[anjing]

Gargantua's lunch box!

 

[Holger]

Pierre:

GB29-L-1000-ME and GB30-L-1000-ME

 

[jensenmann]

Holger, you are totally crazy. I like that  ;D
Anyway, this mixer sounds incredible and since I´ve heard it I´m struggling with my sanity and purse to DIY or not DIY one.

 

[Holger]

Holger, you are totally crazy. I like that  ;D
Anyway, this mixer sounds incredible and since I´ve heard it I´m struggling with my sanity and purse to DIY or not DIY one.

Jens, you can't hide such a project from your wife 

 

[Brian Roth]

Ian (or anyone else for that matter <g>), what is the DC resistance of the VTB9043 10H inductor used for the LF section in the Helios EQ section?  Colin didn't include that tidbit in his Carnhill PDF file.  It may be buried in this (and other Helios threads) on the forum, but I haven't seen it.

I've been "scratching around" on paper with a Helios-type design.....

Thanks!

Bri

 

[ruffrecords]

Ian (or anyone else for that matter <g>), what is the DC resistance of the VTB9043 10H inductor used for the LF section in the Helios EQ section?  Colin didn't include that tidbit in his Carnhill PDF file.  It may be buried in this (and other Helios threads) on the forum, but I haven't seen it.

I've been "scratching around" on paper with a Helios-type design.....

Thanks!

Bri

I don't have one lying around but I do have one in a channel module. I measured it in situ and got a reading of 816 ohms.

Cheers

Ian

 

[KMB-AUDIO]

Just a quick question, what tubes are you all using? I'm starting to order parts and was curious what other people were using.

 

[ruffrecords]

Just a quick question, what tubes are you all using? I'm starting to order parts and was curious what other people were using.

For the 6922 I tend to use the 6922EH or the E88CC by JJ. For prototype testing I have a whole bunch of Russian 6N23 which work surprisingly well. For the 12AX7 I mostly use the 12AX7LPS by Sovtek but I have just ordered a few 12AX7EH because they are reported to be less microphonic.

Edit 2022: JJ E88CC proved to be rather variable so I have standardised on 6922EH. For the other tube I now use a Sovtek 12AX7WA as time has demonstrated they have consistently low microphonics and noise.

Cheers

Ian

 

[KMB-AUDIO]

Can someone check my numbers. I need to order parts for the HT supply and here is what I've come up with following Ian's document. Let's assume I'm going to power 20 Twin Line Amps.
20x15mA=300mA

Vac = 330 x .071 = 234
Iac = 300mA x 1.61 = 483mA
Pac = (330V x 300mA) x 1.14 = 112.86 Watts
Resistor Values: 10000/300 = ~33 Ohms, 10W
Cap Values: 680uF

Does this look like a good candidate for the power transformer? (Besides it not being in stock)
http://www.mouser.com/ProductDetail/Hammond/182K117/?qs=%2fha2pyFadujXoYrQxf7lkJ9xd4tBeF1Pmt5ZLFgMfOo%3d

Thanks!

 

[ruffrecords]

Numbers look god to me. Transformer looks good too.

Cheers

Ian

 

[Holger]

Almost finished, only few hours of work left 

 

[anjing]

Impressive Holger!

 

[ruffrecords]

That is magnificent Holger. Well done.

The picture is not too clear but it looks to me like you are using nuts and bolts to hold the sub-rack end plates to the wood. It also looks like there are holes in the wood where the extrusions are held to the side plates. Can you elaborate?

Cheers

Ian

 

[Holger]

Ian, my wooden side panels are for testing purposes and not final. I have to talk to a carpenter to find a final (and better looking) solution.
Currently I'm utilizing the existing holes in the Fischer extrusions to fix them to the side panels.

 

[nhaudio]

Just a quick question, what tubes are you all using? I'm starting to order parts and was curious what other people were using.

For the 6922 I tend to use the 6922EH or the E88CC by JJ. For prototype testing I have a whole bunch of Russian 6N23 which work surprisingly well.
Ian

Hi Ian, NOS 6n23 will not work as well as 6922Eh or the JJ ? Due to my little experience with tubes, could you explain why?

thanks

Nico

 

[ruffrecords]

Just a quick question, what tubes are you all using? I'm starting to order parts and was curious what other people were using.

For the 6922 I tend to use the 6922EH or the E88CC by JJ. For prototype testing I have a whole bunch of Russian 6N23 which work surprisingly well.
Ian

Hi Ian, NOS 6n23 will not work as well as 6922Eh or the JJ ? Due to my little experience with tubes, could you explain why?

thanks

Nico

I am never quite sure just how close an equivalent the 6N23 is to the 6922/E88CC. Having said that, I have tested a lot of them and they all perform well in the output stages of the EZ Tube Mixer. I have measured the distortion characteristics of all three tubes types in the SRPP configuration I use in the output stage and they all perform well. The level of distortion is very similar, it is just the characteristics of the distortion that vary between types. The differences are so small that I do not expect there to be any audible difference between them once the negative feedback has been applied. The only reason I recommend the EH and JJ types is because they are in current production.

Cheers

Ian

 

[ruffrecords]

Some of you may know that I have been having some serious buzz problems with the EZTubeMixer prototype build. Thanks to Holger's help I have finally fixed it. Further details can be found on the blog:

http://eztubemixer.blogspot.co.uk/

Cheers

Ian