4ch PTP all film rude tube/r47

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soundcollage

Well-known member
Joined
Dec 11, 2007
Messages
71
many thanks to bernbrue! many thanks to the knowledgable members of the forum! ok i lied a bit- i used 3 electros in the phantom section as i would have needed another 3 space rack to fit another 2000µf of film caps in, but i made them easily accessible to any future techs.
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monstrous power 'brick' front side
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I had to mount the 47µf solens  vertically or everything would not have fit, so i put all the power circuitry on the boards i used to sandwich them.
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super-over-rated resistors  are, shockingly, cheaper than appropriate ones and 2 single solder turrets.
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BEEFY
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seperate shielded twisted pair for all ten tubes, because i'm ridiculous.
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16lbs of edcor iron hanging off the back of this one.

currently working with my wife to layout the front panel graphics to silk screen on.
hopefully the 6 cinemag transformers will arrive sometime this year.

 
How on earth do you solder to those tube sockets mounted on stand off? Do you solder them up first and then mount them?

Cheers

Ian
 
mounted them first to make sure spacing of other components was ok then removed and soldered  leads/ resistors to them.
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clear shrink over all exposed pins/ leads so no shenanigans when screwed into place. i wired them in last so as to be replaceable but i'm hoping for at least 20 years out of the nos tubes before i have to pull them so i doubt they'll ever need to be replaced.
 
thanks! it was hard taking a photo of it because of the mirror red powder coat and high gloss nazdar ink. could not use the flash or have lights on in the room. finally got my cinemag iron and NOS amperex 6922's i've been waiting for so should be finished soon after the ink cures.
 
Ha! Talk about a nice project! Any chance we will ever see the schematics for this? With all those crazy controls like "bias", "capacitor", "squish" and "inductor" one have to get curious
 
nothing crazy different going on in the circuit all credit goes to bernbrue, this forum and EMI.  i split his multifunction switch into separate components so i can have the peak mode in pentode or triode (the star and the triangle).  the capacitor and inductor switches are only active when the peak boost switch is flipped to the right. i added two extra caps the original rude tube did not have-- a 0.047µf and a 1µf and i added a 470µH inductor. i flipped the order of the caps and inductors so the caps would drain to ground, eliminating pops without extra resistors (though i guess they would drain fine through the inductors). all of this could be done on a 24p switch with some creative wiring if panel real estate is at a premium or  keeping it similar to the vulture layout is desired.
for now the squish switch inserts a 470k resistor between the 0.22µF cap coming off the 6AS6 screen and ground, though i may put a trim pot in there or another fixed value if i feel like fiddling around.
i wanted to use the rude tube with mics too so i have cinemag input iron and 40dB pads on all 4 channels. cinmag output iron on 3&4 (the pure redd 47's) and edcor XSM15K/600  5:1 iron on channels 1&2 which are less beefy so i imagine will saturate if pushed hard and this is a distortion generator (not to mention they're less than  1/10th the price of the cinemags).
the direct jacks bypass the input iron and go through a 68k resistor to the EF86 grid. i skipped the 100k resistor across the primary of the output in the rude tube schematic that i imagine was there to tame the output level because i believe the higher ratio transformer should do the same, and i added a 100ohm resistor in series with the bias pot to to have some resistance there at all positions of the pot- though maybe 300ohm would be safer- at least 6AS6's are super cheap for now.
 
almost finished wiring, but i have a quick question regarding the cm-9661ah: http://cinemag.biz/output/CM-9661A_schematic.htm
this is all the documentation on it on cinemag's site, and i could not find an answer here or the drip forum on how to wire  it up. my guess is brown to the 1µ output cap, brown/white and red tied together and insulated,  red/white to ground on the primary side. orange to + output and yellow to -output on the secondary. is this correct?
 
Hi Soundcollage,
I just found this thread and I have to say I´m speechless  :eek: :eek: :eek:
This is indeed a FANTASTIC APPARATUS . Did you already test it? I´m building a new Rude Tube at the moment and also splitted the function switch. One for triode/pentode/squish I+II and another one for 6 different peak modes. The 100K resitor at the outputs primary is just for the 1uF cap to discharge. When using it unbalanced it could destroy your mixer input. There should be no difference soundwise. Why did you use an 68K resistor from DI to the grid of the EF86? You did it, man!! Congratulations!!
regards
Bernd
 
Not tested yet-still a few wires to connect and i'm waiting for conformation on the output transformer wiring.
Mine will be used balanced exclusively and its wired floating to the outputs so the transformer should block the dc even if an unbalanced cable is plugged into the patchbay.
The 68k is a habit from my guitar amp building. rather than take the input transformer secondary through a switching jack to the grid i wired the secondary and the 68k directly to the grid. in my limited knowledge, it seemed like it would make the wire going to the direct jack less antenna-like when using the balanced ins.
More knowledgable folk please chime in and correct my ignorance.
 
faceplate completely wired in. the green spaghetti wires are all at ground (mostly connections to the shields of the white wires), so i did not fret over making them super neat.
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the powder coated handles came out even shinier than the brushed aluminum faceplate.
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all is wired in now except the two cm-9661ah OT's that i am still waiting for a wiring conformation on.
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The wiring scheme that you mentioned is correct if the transformer has a split primary, which I think is the case. It is listed as "dual primaries" which could mean that there are two identical 30k primary windings for some reason. In that case you would want to put the primary windings in parallel (brown and red to cap, brown/white and red/white to ground). It will work in either case - you will just get more or less impedance/level step-down than you meant to. You should be able to test this with a steady signal and volt-meter. Connect a signal to brown and brown/white. Measure the voltage across the primary (brown and brown/white) and across the secondary (maybe load the secondary with 10k). If the voltage on the secondary is about 7 times less than the voltage on the primary, than there are two 30k primary windings and you want to put them is parallel (assuming you want 30k:600). If the voltage on the secondary is 5 times less than the voltage on the primary then there are two 15k primaries and you want to wire them in series (like you said).

Best,

Ben
 
Thank you for the heads up on the empirical solution Ben. I fed it a 1.36v sine wave from my modular paia synth and the transformer spit out 0.384v, even when the pitch was swept. 3.54 times less is much closer to 5 than 7, so i went ahead and wired the primary in series as we both suspected was correct to begin with. now i have to dig through my mess for some appropriate fuses and start testing.
 
i'll probably do more tweaking in a bit (low pass is a bit extreme- think dub bass,  bias meter only is useful for a limited range of the pot, peak boost is super subtle as it stands, and i need to lower the 500k on the squish switch) but it sounds amazing so far. got a great harmonica tone on a session over the weekend plugging a green bullet direct into channel one with the gain switch in the middle position and the pre and post drive pots at just under 4.
http://soundcloud.com/fantastic-apparatus/harmonica

i also recorded some songs for my good friend ian to peddle at the kent bluesfest. vocals recorded with an AEA R84 into channel 3 (regular 47) with the gain maxed out. the snippet is from the john lee hooker song "hobo blues"
http://soundcloud.com/fantastic-apparatus/main-hobo-vox

here they are sitting over guitar. the princeton reverb i built for him is close mic'd with an AT ATM250DE going into two channels of green preamps.
http://soundcloud.com/fantastic-apparatus/hobo-rough-bounce
 

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