Divided by Thirteen CeeJay Eleven

Tube or solid-state, this section goes to eleven!

Re: Divided by Thirteen CeeJay Eleven

Postby dread pierat » 21 Apr 2010, 08:27

Sorry, my bad. :oops: It does look like a single 47k loading resistor.
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 21 Apr 2010, 09:18

Looks like a 47k to me too but that doesn't mean that it is. There may be a component under the board, etc.

However, it does make sense to attenuate some signal before V2a.
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Re: Divided by Thirteen CeeJay Eleven

Postby snyder80 » 21 Apr 2010, 12:28

you may be right with the 47k to ground (yellow-purple-orange). By the way TW liverpool uses 56k or 68k to ground but a 2n2-4n7 cap...this gives a different freq rolloff.

But again, does anybody know the voltages or what kind of PT they could be using? Because this has an effect on the preampvoicing.
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Re: Divided by Thirteen CeeJay Eleven

Postby topbrent » 21 Apr 2010, 21:07

Here are some additional views of the CJ-11
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Re: Divided by Thirteen CeeJay Eleven

Postby snyder80 » 22 Apr 2010, 22:25

thank you very much for all those detailed pics :applause:

there definitly seems to be a 47k to ground!

But could you be so kind and check the B+ voltages in the PSU and/or voltages at the Preamp/PI Tubes. it would be good to know if there are about 280 V or 320 V floating around...

Greetings,
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 06 May 2010, 13:46

Hello,
I've been finetuning my Ceejay clone lately and found that 47k dump resistor
definetly works well.
I built it almost completely like in schematic but my trannies are from deluxe reverb.

I had to put 5y3 rectifier in to lower my voltages, b+ is now around 370v. It was
420v with GZ34 (Ouch!). I also used 330 ohm cathode resistor to keep 6v6's happy.

I don't know whats B+ in real Ceejay but my guess is that with 250ohms cathode
resistor it can't be much more than 320-330v.

This is actually quite nice sounding build but I added 100k grid resistor after volume pot,
and 1M grid resistor before cathodyne. I had some blocking distortion when gain was maxed.

I also dont like master volume very much, it seems to be effective only when set lower than about 10 a'clock.
VVR would be much better choise IMHO.
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 06 May 2010, 13:54

sagajam wrote:This is actually quite nice sounding build but I added 100k grid resistor after volume pot,
and 1M grid resistor before cathodyne. I had some blocking distortion when gain was maxed.


So did the grid stoppers cure the blocking distortion?

Also thanks for the update. Interesting that the 47K works well.
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 06 May 2010, 20:34

conger wrote:
sagajam wrote:This is actually quite nice sounding build but I added 100k grid resistor after volume pot,
and 1M grid resistor before cathodyne. I had some blocking distortion when gain was maxed.


So did the grid stoppers cure the blocking distortion?

Also thanks for the update. Interesting that the 47K works well.


Hello,
yes grid stoppers did help, now I can turn volume all the way up.
Overall sound is little bass-heavy and boomy if bass knob is turned
above 9-10 a'clock. But I guess it is just the way Fender tonestack should sound like...
I guess it would be easy to cut some bass with smaller coupling caps, I probably will try that soon to get
more useful range for bass knob.
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 07 May 2010, 15:59

I was trying to cut some bass today and I found that reducing
v2a cathode bypass cap from 22µ to 4,7µ gave really nice balanced tone.
Bass is less boomy and there is a little less gain, but there is still plenty of it.
I also have 47p bright cap and 25k mid pot. This thing is really starting to sound
wonderful now :D
Oh and I'm using Eminence GB12 speaker, which seems to be really good
match with this circuit.
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 07 May 2010, 17:10

I just realized why master vol didn't sound right.
In schematic it is wired like cross-line master but it definetly
looks like lar/mar in pictures. So I think it should be wired like this:

http://verosurfcam.com/Lar-Mar_PPIMV.jpg


I haven't tried it yet but I'm pretty sure it will sound better.
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 08 May 2010, 11:39

I have drawn up a schematic based on what what has been learnt in this thread. Have a look and see if I have missed anything.

I have left out the MV because I will implement this in a 5E3 with a VVR - which is a better way to go IMO. If anyone can point me to a well drawn LaMar MV I will include it in the schematic.

Question for sagajam:
Looking at the schematic now, it would also make sense to add a grid stopper to the third triode. Did you try this?
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 08 May 2010, 16:14

conger wrote:I have drawn up a schematic based on what what has been learnt in this thread. Have a look and see if I have missed anything.

I have left out the MV because I will implement this in a 5E3 with a VVR - which is a better way to go IMO. If anyone can point me to a well drawn LaMar MV I will include it in the schematic.

Question for sagajam:
Looking at the schematic now, it would also make sense to add a grid stopper to the third triode. Did you try this?


I didn't try grid stopper with third triode because I didn't find it necessary..
I rewired master today as LarMar and now it works fine. It is actually really good master volume, but I would still replace it with VVR.
Cleans and semi-cleans are really gorgeus and punchy, higher gain sounds are ok too but maybe a litte fizzy to my ears.
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Re: Divided by Thirteen CeeJay Eleven

Postby Ellis Redding » 08 May 2010, 20:55

In a nutshell, it is all Fender deluxe...but a clever blend of two classic era's.


Looking at your schematic It appears to be a cathode biased black face Princeton without feedback loop, a few mods and value changes. Or just a black face Princeton with a few mods keeping it short. I would be with you on the tweed deluxe part, except that this uses the GZ34 (also same as the black face Princeton), the 5E3 used the 5Y3. That's a major difference in performance out of the amp. Thank you for the schematic.
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Re: Divided by Thirteen CeeJay Eleven

Postby Ellis Redding » 08 May 2010, 20:58

sagajam wrote:I just realized why master vol didn't sound right.
In schematic it is wired like cross-line master but it definetly
looks like lar/mar in pictures. So I think it should be wired like this...

I haven't tried it yet but I'm pretty sure it will sound better.


You are correct. I would guess that the author of the schematic took liberties?
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Re: Divided by Thirteen CeeJay Eleven

Postby Ellis Redding » 08 May 2010, 21:27

Image


Carbon comp resistors, "For that Mojo vibe"... :lol:


Image


20uf caps for supply filtering? Was that value chosen to get more Mojo out of that 5AR4? :scratch: The whole thing sounds like it would be great in the studio. :roll:

$2000 for a cobbled together Princeton clone? Pick up a silverface Princeton and put the bias supply (cathode/fixed) on a switch. Put the NFB loop on a switch, cap values to taste. You'll have a more versatile amp at 1/4 of the cost. :wink:
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 09 May 2010, 11:07

A couple of errors corrected:
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Re: Divided by Thirteen CeeJay Eleven

Postby sagajam » 09 May 2010, 11:34

conger wrote:A couple of errors corrected:


Hello, you have 470ohms cathode resistor for v2a, should be 4k7 ohms,
otherwise that looks good :)
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 09 May 2010, 11:40

topbrent wrote:The pull boost switches in a 100k resistor in series with the fixed 6.8k mid resistor on the bass pot and switches in a 250pF with the existing fixed 100pf bright cap to enhance the sparkle factor when pulled.


Are you sure about the way that the boost is implemented? From the pictures it looks like the 6k8 is permanently wired between the bottom of the bass pot and ground (back of pot). All the switching takes place on the back of the Vol pot. Also there is an unusual brown (ground wire?) going from the Vol pot switch to the first triode ground point. Not sure why that is there.
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Re: Divided by Thirteen CeeJay Eleven

Postby conger » 09 May 2010, 16:55

sagajam wrote:Hello, you have 470ohms cathode resistor for v2a, should be 4k7 ohms,
otherwise that looks good :)

Yes, I think you are right. An awful lot of cold biasing going on in this amp. Schematic updated.
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Re: Divided by Thirteen CeeJay Eleven

Postby snyder80 » 09 May 2010, 19:34

conger wrote:
topbrent wrote:The pull boost switches in a 100k resistor in series with the fixed 6.8k mid resistor on the bass pot and switches in a 250pF with the existing fixed 100pf bright cap to enhance the sparkle factor when pulled.


Are you sure about the way that the boost is implemented? From the pictures it looks like the 6k8 is permanently wired between the bottom of the bass pot and ground (back of pot). All the switching takes place on the back of the Vol pot. Also there is an unusual brown (ground wire?) going from the Vol pot switch to the first triode ground point. Not sure why that is there.



I think the boost is designed in a different way, too.
It looks like there is that cc 100k goes between the pot´s (ungrounded) GND-Side (lug 1) and GND (the brown wires). Just have a look at the pics on page1 !

But that should give you just a tiny amount of "boost" and unusual for me. Its more common to insert the 100k in parallel from wiper to GND and in "boost" it simply gets switched out...

Anyhow, keep the solder hot

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