Jet City Mods

Re: Jet City Mods

Very relevant thread for me, as I've been eyeing a JCA22h for a while now. Thanks for the links.
 
Re: Jet City Mods

I'm sure I can apply this to my JCA20H crunch channel, since it's the same thing. I found the slope resistor mod to be pretty useless, so I already have a hole drilled. Need to buy the switch, but I was planning on getting back in there anyway. Thanks for the research.
 
Re: Jet City Mods

changing the slope resistor is only really useful with other mods. In the stock form you dont really get much of a noticable change.

You are right you should be able to apply these to the jca20 also.
 
Re: Jet City Mods

A quick question, Toe-Knee. When I read the description of the crunch/clean mod, I don't really get it. As it stands, there's a single resistor feeding the gain pot. He talks about replacing it with three, but I don't really understand how it's configured. It sounds to me like the 1M in place there is switchable between one 475k or two, but I don't understand how the 39k is hooked up or what it would look like on the schematic or why or if it requires two switches. It's a mod I'd love to do, even better if I could put a mid cut mod on the same switch, but I just don't get it.
 
Re: Jet City Mods

The second switch is a bright switch. What he's done is taken the clean/crunch/bright section from the SLO.

The 39k resistor is connecting the signal to ground. You can see it in the schematic below. I have also added a photo of how it is done in the SLO as it is a lot easier to make out. The 39k resistor is the one that is going from the switch to the bus wire.

Switch1.jpg

clean crunch.jpg
 
Re: Jet City Mods

One more question. The gain pot in the JCA20H is 1M, as is the resistor that is marked here as R10. I assume that the 470k would no longer be correct here? Do they each need to be about 1M, and the 39k bumped to about 100k?
 
Re: Jet City Mods

Hi sorry about the late reply i've been meaning to get back to you but it kept slipping my mind. Ideally you will want to change all of the values to the SLO values for the mod to work as intended.
 
Re: Jet City Mods

Toe-Knee said:
The second switch is a bright switch. What he's done is taken the clean/crunch/bright section from the SLO.

The 39k resistor is connecting the signal to ground. You can see it in the schematic below. I have also added a photo of how it is done in the SLO as it is a lot easier to make out. The 39k resistor is the one that is going from the switch to the bus wire.

View attachment 47929

View attachment 47928
Click to expand...

That has to be some of the neatest wiring/soldering I've seen on here.
 
Re: Jet City Mods

Tony, do you know if the HDM and 22H are wired the same for the footswitch? I know the 22H (and I forgot to look at it on the one I had apart) is different than the 50/100, but I can't remember if the HDM is different.

For the 50H and 100H I modded, all I did was add a switch to the front and replace the switching mono jack with a shorting jack. That way, the front panel switch is defeated when the footswitch is plugged in.
 
Re: Jet City Mods

Soulcrusher_X said:
Tony, do you know if the HDM and 22H are wired the same for the footswitch? I know the 22H (and I forgot to look at it on the one I had apart) is different than the 50/100, but I can't remember if the HDM is different.

For the 50H and 100H I modded, all I did was add a switch to the front and replace the switching mono jack with a shorting jack. That way, the front panel switch is defeated when the footswitch is plugged in.
Click to expand...

I believe theyre all the same.
 
Re: Jet City Mods

I'm resurrecting this because I'm curious if people still play this amp and what mods they have done to it?
So far I only did the 'choke' mod but I'd like to do some other stuff like making the crunch channel more clean and maybe do some voicing tweaks on the lead channel.
Oh, and btw thank you Toe-Knee for posting those links!
 
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Re: Jet City Mods

I've played these Jet City amps in a shop that also brings Hughes & Kettner.
At least tonewise, IMO the Jet City amps are way better than any of the H&K heads I've tried.

The tone is a bit looser, doesn't sound as cold/clinical. The Jet Cities (?) sound a bit more elastic and "alive" for lack of a better term, whereas the H&Ks are too compressed and just sound and feel extremely "Modern".
 
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Re: Jet City Mods

Nightburst said:
Thanks, I tried but it seems locked down?
Click to expand...

You have to register to view the content. You can't just lurk like you can here. Just a warning the mods mods mods section is a monster! If you want something specific you can just ask too, you will get no shortage of answers.
 
Re: Jet City Mods

Joey Voltage said:
You have to register to view the content. You can't just lurk like you can here. Just a warning the mods mods mods section is a monster! If you want something specific you can just ask too, you will get no shortage of answers.
Click to expand...

ok thanks, I registered now
 
Re: Jet City Mods

Hi all, sorry for resurrecting an older thread, but I've tried registering at slocloneforums but it is asking about Joey's favorite cat!
I've tried guessing it, but how am I supposed to know that! :-) (or is it a subtle way of closing registration for a while or something...?)

Any cat names appreciated!
 
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