New amph day: Jet City JCA22H

[marnold]

Hi all! It's been a very busy past few months (and extraordinarily cold past few weeks), so it's been a while. Yesterday I got myself a new toy, though, a Jet City JCA22H! A local shop was no longer going to be carrying them, so I got the head for $340. I rescued it from being shipped back.

It is in many ways similar to my JCA20H, both in looks and function. The JCA22H has two channel as opposed to one on the JCA20H. The crunch channel is just like my JCA20H. The overdrive channel is the famous Soldano SLO preamp circuit. Lots of gain on that one, although past six on the knob it adds more compression and "girth" than there is more distortion. Sustain for days! It comes with a footswitch to go between the two channels.

One of the big features I was looking for was an effects loop. The JCA22H has a tube-driven serial loop. It certainly gives new life to my pedal collection. I've been dialing in my DD-6 for a good metal lead delay tone. I tried my EX-7's A/DA flanger model and ran through a bit of "Ain't Talkin' 'Bout Love." Both made me cackle maniacally.

I'll probably want to swap the tubes (especially in the preamp) for JJs so smooth out the distortion a bit and make is less hissy. Those tubes did the trick on my JCA20H. Now I just have to try to sell my old one . . .

 

[Robert]

Whoa, you got 2 Jet City 20ish watter heads! Crazy guy!

Nice to have a clean channel on it though, I bet.

I sold mine - wasn't using.

 

[piebaldpython]

Hey Marnold.......nice score. How's the clean on those Jet City amps? Is there alot of headroom before it breaks up?

 

[Tig]

Cool! HNAD :dance
Nice to hear from you, marnold.

 

[marnold]

Hey Marnold.......nice score. How's the clean on those Jet City amps? Is there alot of headroom before it breaks up?

No, there isn't. Clean headroom is virtually non-existent on the overdrive/SLO channel. On the crunch channel, just like on my JCA20H, humbuckers start to break up with the preamp at about 1. Single coils, of course, are more forgiving. If people want cleans out of this, most dime the master and slowly turn up the preamp. Some mod theirs to give more headroom or put a 12AT7 tube in the V1 position. One thing I've noticed is with a delay pedal in the loop, it gives the illusion of being cleaner than it really is at low preamp settings.

I had looked at a JCA20HV which is basically the JCA20H except that it is voiced somewhat darker with less gain. It also has a depth switch and a Mojo Tone solid state effects loop. I tried one out at the store, but there was something majorly wrong with it. It sounded like I had a bad cord and someone was constantly jiggling it.

Since I play mostly bluesy or hard rock/metal stuff, it has enough cleans for me. If you're looking for a Fender clone, look elsewhere. If you are looking for a hot rodded Marshall, this will do the trick.

I didn't get it because I hated my JCA20H. If you look at old posts, I wanted an effects loop on it from day one. Delay sounds SOOOOO much better now.

 

[piebaldpython]

.Since I play mostly bluesy or hard rock/metal stuff, it has enough cleans for me. If you're looking for a Fender clone, look elsewhere. If you are looking for a hot rodded Marshall, this will do the trick.

I didn't get it because I hated my JCA20H. If you look at old posts, I wanted an effects loop on it from day one. Delay sounds SOOOOO much better now.

Thanks for the input Marnold. I play mostly blues and don't need an amp to go into metal territory. I like the idea of a 2-channel amp, especially if one of the channels is mostly clean. The Tubemeister 18 tickles my fancy.

BTW....I am so sick of this snow and cold that we have had over here in Philly lately. Yeah, nothing compared to what you went through but it hasn't been this cold in 20 years. The Delaware river froze over and if we have a quick thaw with an inch or two of rain today, it could make things interesting for some areas along the river. UGH!!!

 

[marnold]

Thanks for the input Marnold. I play mostly blues and don't need an amp to go into metal territory. I like the idea of a 2-channel amp, especially if one of the channels is mostly clean. The Tubemeister 18 tickles my fancy.

I think this video does the best job of showing the range on this amp:

 

[Eric]

Congrats on the new amph, marnold. I liked the jet city I had, but I was never in a position where it was applicable to turn up when playing with others, so I sold it. It was good though.

 

[duhvoodooman]

Sweet pick-up there! Nice to have the flexibility of the two channels.

I didn't get it because I hated my JCA20H. If you look at old posts, I wanted an effects loop on it from day one. Delay sounds SOOOOO much better now.

Yeah, I've come to the conclusion that an effects loop is a NECESSITY with a gainy amp, if you use time-based effects (reverb, delay, chorus, phaser, flanger, etc.) with any frequency. Running them through the cranked preamp sounds like ****....

 

[piebaldpython]

Marnold......thanks for the video showing what the amp can do. It was cleaner than I thought it would be. EFX loops are most certainly a necessity on a gainy amp.....no doubt about it.

 

[marnold]

The only problem with the effects loop is that it is renewing my desire for a reverb pedal. And here I had been GAS free for so long...

 

[marnold]

Maybe DVM can help me with this one:

One thing that I've noticed with my JCA22H, when I first power on the amp (with it in standby), the bottom of the V3 preamp tube seems to glow brighter for a brief moment before warming up like the other ones do. I don't know if I've got a tube going bad or if it is "reflected" light from underneath from V1 and V2 warming up. On my JCA22H V1 and V2 have shields on them while my JCA20H did not.

I've got my original Chinese tubes from my JCA20H in case of emergencies. I guess I could swap one out and see what happens.

Edit: I can answer my own question. I swapped the tube out and the new one doesn't glow like that. Also the amp became remarkably less noisy--even though I didn't think it was terribly noisy to begin with. I was surprised. At first I thought I had screwed something up because the crunch channel was dead silent. I mean, it wasn't turned up THAT loud, but still. Simplest solutions are the best.

 

[marnold]

Speaking of help from DVM . . .

As I understand it, the V3 tube is half shared between the crunch and OD channels and the other half is a "cathode follower." Every article I've read gives a technical explanation of what a cathode follower does, but none of them say in layman's terms what practical benefit there is for the guitarist.

 

[duhvoodooman]

As I understand it, the V3 tube is half shared between the crunch and OD channels and the other half is a "cathode follower." Every article I've read gives a technical explanation of what a cathode follower does, but none of them say in layman's terms what practical benefit there is for the guitarist.

A well-stated summary description from the Valve Wizard website:

"The AC-coupled cathode follower is normally used as a means of coupling a high output impedance to a low input impedance with minimal "insertion loss" (i.e., not much loss of signal amplitude). The cathode follower has very low input capacitance and a very high input impedance so it will not load down the previous stage, and very low output impedance so very little signal is lost even when driving a fairly low input impedance. The cathode follower is an excellent buffer stage for driving a tone stack or effects loop, or any circuit which would otherwise present a heavy load to a "normal" stage."

So, in a nutshell, a cathode follower stage (with its low output impedance) has the ability to drive a subsequent circuit (a tone stack is the typical example) that would otherwise cause a significant amount of signal loss if it was connected directly to the previous gain stage (which has a high output impedance). Basically functions as an internal buffer in the amp.

BTW, I can help you with that Reverb pedal thing; PM me if interested.

 

[sunvalleylaw]

Nice! Happy belated new amph day!

 

[marnold]

Thanks for the explanation, DVM. It makes sense now.

 

[kidsmoke]

Very cool Rev. I too purchased a gainier amp with a loop, and I've not really explored that angle on things. This thread helps. I'll have a NAD thread soon.

 

[Monkus]

HNAD !!! Congrats!