Cole Max - Feed Your Vinyl to this:

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Cole Max


Some quick facts

phono stage:
Tubes are E180F and 2C51
LCR direct coupled
Silk Step up transformers 10x/20x
Mute and stereo/mono
All the best bits inside


power supply:
FCUPS film cap power supply
5AR4 tube rectifier
ULNFS (ultra low noise filament supply)
connected by umbilical
Next: more.
 

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I am really trying to use this phono stage very soon and would greatly appreciate some help. Absolutely nothing is labeled which makes it quite difficult, so I popped the bottom off and tried to trace the circuit.

I am attaching a pic of what I think I've figured out thus far, but have quite a few questions left. Also make sure my notes are correct please!

The inputs closest to the ground post (right side when looking from the front) are the MC as they go to the stepup switch (gain of 10x/20x). MM obviously the other. In the back the two switches (always viewed from the front as the picture) are MM/MC on the left and Gain on the right. But which position is which for both? The stepup transformers are on the left and the LCR transformers are on the right leading me to conclude that the 2C51 tubes are on the left and the E180F output tubes are on the right.

That leaves the front two switches as mute and stereo/mono. Which is which? Also which position for each?
 

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I sent them emails using their website and no response. It looks as though my phono stage is not working correctly. For one the mute switch does nothing. The gain is very low even though I did figure out which is 10x and which is 20x. I tested my tubes and they test very strong, so that isn't the issue.

I could really use a bit of help.
 
It would make more sense for the E180F to be the input tube, low noise and high gain, directly after the input step up transformer, the LCR would be between the two tube stages but is placed where it is for aesthetic reasons.

Remove the bottom plate, the E180F will have heater connections at pins 4,5. The 5670 at pins 1,9.

What does it look like when you remove the bottom plate?.. This was probably designed by Thorsten Loesch, he posts regularly enough at diyhifi.org, you could try there.
 
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I did send Thorsten a message since noone at DIYHFS answers emails. I removed the bottom plate when I was trying to trace the circuit, I didn't get as far as figuring out which pins were which, I guess that is the next step.

Thanks.

Viewed from the underneath of socket, 1 thru 9 starting at the spacer and moving clockwise, yet if the heaters light up, then the tubes are in correct location already as they are not pin compatible.

Nothing looks burned out or broken/loose?.
Problem is the same, and at the same level for both channels?

Was this built as a kit?, what can the previous owner tell you about it, or did you buy it from Brian Cherry?

Be sure that your turn table and amplifier are both functioning correctly.

In circuit voltage measurements will tell you a lot more..
 
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Thanks Hanze,

I did confirm that I had the tubes in the right sockets by the heaters. I will need to measure voltage soon.

This was built at the factory, not a kit. Everything looks top notch under the hood. My system works will all other sources, so I've rule that out and the table spins at the correct speed. I haven't ruled out a bad cartridge yet, but seems a bit unlikely.
 
It lives!

Ok, through tracing the circuit I realized that I was totally off on the inputs and outputs. What I thought was the MM input was really the Output and visa versa. I still don't know what most switches do, but I figured out the mute and the step-up gain switch.
 
So in the first picture you can see my light pencil marking of which input is which (and output).

Second photo shows what I figured out for gain (although technically the label should be 10x/20x), tube locations, I think the right front is mute and right left is stereo/mono. Not 100% sure.

The phono is dead quiet with my ear in the horn of my 95db speakers, that is good news and it images like a mo-fo.
 

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