Looking at Buliding a Stereo MILA

I have found it!

Here

Here is the configuration. This is the third time I'm posting this. My computer keeps crashing. :?

T1 = CM 2940
T2 = JT-11p
J2 = Inst jack

Positions are 37.5, 150, 150 -20 db, 10k

P1 to XLR 2

A1 to T1 ct
B1 to T1 pri +
C1 1k resistor to B1 and 220 to P4
D1 to T2

P2 to XLR 3

A2 to T1 pri -
B2 to A2
C2 1k to B2 and C4
D2 to T2 pri -

P3 to J2

A3 to T1 sec
B3 to A3
C3 to B3
D3 to T2 sec

P4 to C1 (through 220)

A4 n/c
B4 n/c
C4 to C2
D4 n/c

Any holes in my logic?

BH

Today I have built the power supply!

Is the neon bulb supposed to shine? It is 117v and it has voltage...

The whole PSU is spitting out about %15 unloaded across the board. I am not concerned with the plates, but 6.95 for the heaters bothers me. Is there a pad I should throw in? Is this normal for and unloaded AC heater circuit?

1 more supplier and a stepper bit to go before I can start the rest...

Thanks!

6.95 sounds o.k. to me. There will be a bit of a voltage drop with the tubes in...

Thanks Pucho...

I just sort of sussed my neon problem out... I'm blowing bulbs. Duh-

I'll go think about some V=IR stuff and come back...

:guinness:

I just blew my last fuse and I stole that one... so no more DIY tonight...

I think I have it, though.

Application sheets are marvelous.

:guinness:

Found another fuse and got it lit up. Amber neon :idea:

One small note, in the turret board layout pdf posted here:
http://musiciansgig.com/mila/MILA2_updated.pdf
I think you can leave out the wire bridge between the two turrets on the upper left, that is the wire that connects the Zobel network resistor to R5 = 1M Ohm - otherwise the input transformer will not get disconnected when you use the HI-Z input.

I did my own layout with all of the B+ mounted on a JJ 32+32.

The heater bias has it's own turret board that looks a lot like the schematic.

I'm going to start the chassis mounted components tonight if I don't play poker...

Hmmm... Where'd that layout come from? It's not mine. I don't believe I ever published one.

[quote author="NewYorkDave"]Hmmm... Where'd that layout come from? It's not mine. I don't believe I ever published one.[/quote]

came from a member I forgot who. I believe there was a thread about it....

Hi Dave, Pucho,

A member named "Nadege" published that layout some time ago. I built mine according to that layout and it works fine. Sounds very nice BTW. I dumped it on my webspace here along with other MILA info: http://musiciansgig.com/mila/

Thanks for the design,

M.

Hey All-

I have all of the transformers, can caps, turrets and anything else you might bolt to a chassis and have begun wiring... So:

Is pin 9 connected to anything?

Or is that for 12.6v operation...

She is looking like a pinup girl from the 50's. (with teflon wiring)

Thanks.
:guinness:

So yeah.

A little research answered the above.

I'm sure I'll have better questions next post.

Well...

She's alive!

Now for the hard part... she is sick. I am able to pass signal, but it 's a clipping distortion and a hpf.

Volts:
(proper volts) my volts

B+ (+300) +314
R21/C8 ((+246.6) +248
R22/C9 (+197) +196

V2
R17/C6 (+132.3) +105.9
R16/C5 (+2.58) +3.26

V1
R8/C3 (+91.5) +86.9
R12/C4 (+70.6) +60
R7/C2 (+2.3) +2.43
R11 (+1.73) +1.88

How out of tolerance am I?

Oh yeah... 5.94v AC for the heaters.

Anything to help a brother out?


:guinness:

I have a solid sine wave up the grid 1 of V1, but it starts to overload at the anode.

I am double checking the wiring for V1... I think it's right...

I'm starting to wonder if I have a batch of bad 12av7s.

The same problem happens with V2 when I inject signal through the grid resistors R14 & R15 and collect it at the anode.

Any troubleshooting advice would be grand...

Glorious success!!!

This is true DIY. And absolutely the most complex thing I have done. I still have to wire up the other input switch and finalize the faceplate. Then I will post pics.

Thanks NYD. I owe you lots of beer, tea, and knishs...

hi babyhead,
good job! can't wait to see her.
for the sake of others (though you've obviously done well with figuring things out yourself) what was the cause of the problem? your voltages seemed o.k. and within tolerance (to my untrained eye and mind). was it your 12AV7 tubes?
cheers,
grant

The biggest lesson was making sure the test rig was correct. I had a bad cable.

Why were the tubes distorting? The tone gen was too hot. I pushed it because of the short leg... then I hit the db switch at found myself at +10. Imagin that the tubed would have a, how did I say it, clipping distortion and hpf? Dooh.

Learned a lot. Enough not to get shocked yet!

A good set of test cables goes a long way. As does a decent scope and tone generator. good Job in figuring it all out. :thumb: