AN Wonderland/JM 100w layout

[jazzbass]

hello norburybrook,

it's a strange year for the components, probably a world crisis ... in addition to some defective components or shipping errors now I have a serious problem, in the reverb line there is something wrong.
With the latest changes you suggest the amp is splendid and the reverb sounds wonderful too but ... after a while its volume drops drastically, it becomes almost inaudible while the rest of the amp continues to work well.
I have tried everything, check the soldering, replace the connection cables, replace the tank, replace the return pot (I only need to change the send pot), I have also tried with some punches on the chassis but there is nothing to do, it works for a while and then disappears.
Sometimes it starts to work again by unplugging and reattaching a cinch of the connection cable, sometimes I turn on the amp and the reverb is not heard even though the pots are set high then, playing and without doing anything else, it starts working normally again ..... help .... I don't know what to do anymore and I need help.

Thanks
A hug Franco

[rccolgan]

I'm wondering if this is a tube thing. When the signal cuts out, have you measured the voltages again? Perhaps that can be telling. I helped a friend troubleshoot an issue once and it turned out to be the internal coax cabling had a intermittent short to the ground shield. Maybe another place for chop sticks and disconnecting the ground sleeve.

[martin manning]

Leaky coupling cap causing the bias to drift? Again measure voltages before and after.

[jazzbass]

Hello to all,

today the amplifier returns home, moreover it is very much liked by the guitarist friend and I thank Rayan, Martin, Norburybrook, Bombacaototal and all the guys who have studied this amplifier and have "made it sound" as it should.
I'll follow your advice and then keep you informed. I got an idea of the problem and I really think it is the fault of a shielded cable as suggested by Rayan.
I'll check the tensions anyway.
See you tomorrow, a hug.
P.S. thanks to the large TAG community, made up of well-trained and very generous guys, a real community.

A hug

Franco

[jazzbass]

Hellow to all of you,

I followed your suggestions and replaced the shielded cable to and from the Send / Return pots and the reverb is now working smoothly, thanks everyone.

As planned I have inserted a FET card in the JM / Wonderland.

Then power supply of the relay, relay, FET card with a 10K potentiometer inserted in the front panel instead of the Jack-FET. Having only one relay I chose to use a very simple pedal, like the Fender one, to activate and deactivate the reverb adding a switch on the side in case I do not want to activate and deactivate the FET continuously but only for an entire session.
When I activate the card I do not get variations in sound quality but bigger, more authoritative notes. If I activate a distortion or an overdrive in front of the amp, I have a very nice and important sound, much more convincing than the only sound obtainable with the pedals but without FET.
Apparently a successful experiment.
I am attaching some photos.

A hug
Franco

[jazzbass]

Hi,

a short movie,

Franco

[norburybrook]

Franco,

Are you saying that the FET isn't on a footswitch but the reverb is? good to know the FET is working well though

Nice suede cab

oh....., your grill cloth is side ways

M

[jazzbass]

Franco,

Are you saying that the FET isn't on a footswitch but the reverb is? good to know the FET is working well though

Nice suede cab

oh....., your grill cloth is side ways

M

Hi norburybrook,

the amp is a regular JM / Wonderland with the modifications suggested by you, Colgan, Rootz and others on these pages.
To activate and deactivate the FET board that I have installed inside the amplifier I use an external pedal from Fender, the same pedal that is used in a TwinReverb to operate the reverb.
I know that the rhombuses of the front canvas is side ways but I had to do with the same expensive piece of canvas both the front of the cabinet and the amp. I made "of necessity, virtue"

A hug
Franco

[norburybrook]

Franco,

Are you saying that the FET isn't on a footswitch but the reverb is? good to know the FET is working well though

Nice suede cab

oh....., your grill cloth is side ways

M

Hi norburybrook,

the amp is a regular JM / Wonderland with the modifications suggested by you, Colgan, Rootz and others on these pages.
To activate and deactivate the FET board that I have installed inside the amplifier I use an external pedal from Fender, the same pedal that is used in a TwinReverb to operate the reverb.
I know that the rhombuses of the front canvas is side ways but I had to do with the same expensive piece of canvas both the front of the cabinet and the amp. I made "of necessity, virtue"

A hug
Franco

Franco : Excellent , could you show me how you've wired it to work with this footswitch?

Regarding the cloth I hear you I have thought about doing the same from time to time , hence me noticing

M

[jazzbass]

Hi norburybrook,

to take advantage of a FET card and its pot in the front cover I simply copied this layout

2nd_gen_hybrid_rev110410_750_136.pdf

found on page 1 in the discussion "2nd Gen hybrid", contributed by Charlie Wilson.
You can see how to activate and deactivate the relay in the test documented in the attached video which I then made with a Jack to which you can connect a Fender reverb pedal that grounds the relay power supply and then activates the FET board allowing the signal to pass through contacts NO
I have preceded the Jack by a small switch to allow manual activation.
If you want suede I have the shop near home

[nicosci]

Hey all, longtime lurker here. I have a Ceriatone JM and I've been following Ryan Colgan's YT on how it compares to the TR Sig.

Here's something I noticed about the CJM's power supply line/string. See, the AN layout shows 2k2/22k/2k2 dropping resistors at the power board and CJM had 1k5/22k/2k2. So this for me opened a can of worms as I have been passively wondering why I had higher V1 voltages (177v-180+v) 180+ volts at V4 as well, BUT AT THE SAME TIME have lower 6L6 Plate Voltages (430v+ ish) as well, when AN layout shows 445v ...and Nik and even the others saying it should be more like 450+v thereabouts. ...Also, coincidentally, I'm always annoyed how the amp is not really that snappy or marshmallowy as JM's TR Slow Dancing clip for example. Not happy with headroom at loud as well..(plate voltage?) So I went as far as converting the mains to 100uF (50w amp) as suggested in this thread which helped that snap but you can feel somethings still up and I know the voltages doesn't line up. I know its something about the different values on the dropping string. It's only now after re tubing that I got interested again in investigating, also come Ryan's Fairfield County JM build vlogs. > So here's my forensic sort of analysis, from an everyday builder player standpoint of course: (My goal is to ask the knowledgeable ones if this is a good call or if I'm missing something or if I'm wrong) :

>>> 1.) CJM Plate voltages are lower cause the 1k5 3w lets more voltage to the next dropping stage. 2.) CJM PI resistors are 100k & 110K instead of 120/110 cause of the said effect to the next stage, lowering the voltage back to be consistent. 3.) X5 line(Cer. Layout)/b4 line(AN layout) supplies BOTH V4 & V2 on TR/AN layout. WHERAS in Cer. layout, X5/b4 only supplies V4, which is consistent w/ my observation that my V4 voltages were high. 4.) Then Ceriatone has the X6/b5 line supplying BOTH V1 & V2 which could very well be to compensate for not having that "Fet drag" 220k resistor on power board by the last filter (X6/b5), as mentioned by Ryan in his recent Fairfield Build video. As supplying both v1 & v2 instead of just v1 will attempt to tame the voltage (quite unsuccessfully in my case if my theory is right) as the Fet drag would do in AN layout.

So there. My next question is ; If I change the routing like AN with the power line to v4 is same as v2 , v1 is standalone but with an added FET drag resistor, and if I reverse the Ceriatone values changes to be like AN , parts encircled in blue (attached pic), it will be a cohesive reconfigure to be 100% TR/AN circuit?

I'm guessing the Ceriatone differences in power supply config is to technically make it a different circuit enough as to not be considered copying or violation of copyrights etc?

Cheers,
Nick

TAG theory nick.png

[dbharris]

Yes, tweaking the voltages will change the feel and timbre of the amp. Keep in mind TR had a special wind version of the standard twin PT and every build has varying tolerances. So, if you are trying to nail the voltages that may mean diverging from values in the schematic.

One other thought as someone who loves that YouTube clip of John testing the TR amp...that was recorded on a phone over a decade ago. Yes, it sounded fantastic. And yes, it certainly did not sound exactly like that in the room. You can hear the mic compressing and even slightly distorting the sound if you listen closely on good speakers. Just my two cents as someone who built a clone and had that clip as a reference point as well.

-Dan

[sluckey]

430 versus 445 is only a 3.5% difference. That could easily be explained by differences in line voltage, bias setting, meter calibration, etc., or even a combination of all these factors. Even two identical PTs could have this small difference. Not something I would be concerned about at all.

[nicosci]

Yes, tweaking the voltages will change the feel and timbre of the amp. Keep in mind TR had a special wind version of the standard twin PT and every build has varying tolerances. So, if you are trying to nail the voltages that may mean diverging from values in the schematic.

One other thought as someone who loves that YouTube clip of John testing the TR amp...that was recorded on a phone over a decade ago. Yes, it sounded fantastic. And yes, it certainly did not sound exactly like that in the room. You can hear the mic compressing and even slightly distorting the sound if you listen closely on good speakers. Just my two cents as someone who built a clone and had that clip as a reference point as well.

-Dan

Hey Dan, Exactly, I realize I have to adjust a lot of things if I even wanna come close to the AN voltages, as things impact other things , as I pointed, hopefully I am not missing anything, as I am having serious thoughts of doing it someday.

On that Slow Dancing clip, I agree, even my amp will sound more like that if I record it in certain ways. But still you can't deny there's something extra going on, not sure how much of it is the amp and how much is TBO or even the nos tubes lol.

Still you have to consider the voltage differences especially the V1 plates as not being negligible especially with the said power routing/ value differences, pretty significant I'd say and you'd wonder why they did it in the first place.

I appreciate your thoughts greatly thanks - Nick

[nicosci]

430 versus 445 is only a 3.5% difference. That could easily be explained by differences in line voltage, bias setting, meter calibration, etc., or even a combination of all these factors. Even two identical PTs could have this small difference. Not something I would be concerned about at all.

Point taken but the other differences, frankly concerning, in light of people getting excited how similar the circuits were. I mean, at one point I had 425v at plated and 180+v on V1 I was like hey that'd change the dynamics significantly, how on earth can I have a higher voltage down the line and lower up front. Anyway I appreciate the help.