JCA OWNERS!!! (RE)JOIN THE JET CITY LOUNGE!!!

[Tortuga]

Well I already ordered the Ruby EL34b

Also I just noticed back a few pages that Grimespace post a video of mike soldano running different tubes in a JCA50. Unfortunately, my connection is too slow to watch it at the moment.

What's up with that video?

Well either way, it sounds doable.

So you got a JCA22h?

That video just came out, so nobody's sure whether the transformers are same as what we have in our older heads. Bottom line was, Soldano stated that you could run pretty much anything up to KT88s with just a few resistor changes - at least on the new head he was working on. They were very specific in that they weren't advising anyone out there to perform any of the mods they were doing, even setting bias, which was done with an oscilloscope.

Good luck, and welcome to the club

[Jay]

Well I already ordered the Ruby EL34b

Also I just noticed back a few pages that Grimespace post a video of mike soldano running different tubes in a JCA50. Unfortunately, my connection is too slow to watch it at the moment.

What's up with that video?

Well either way, it sounds doable.

So you got a JCA22h?

That video just came out, so nobody's sure whether the transformers are same as what we have in our older heads. Bottom line was, Soldano stated that you could run pretty much anything up to KT88s with just a few resistor changes - at least on the new head he was working on. They were very specific in that they weren't advising anyone out there to perform any of the mods they were doing, even setting bias, which was done with an oscilloscope.

Which makes me think the Transformers are still the old parts.

RFPC had a few KT88 vids, but he took them out for some KT66s. I wonder if Doug notified him it may not be in his best interests for prolonged usage.

[Jay]

Well I already ordered the Ruby EL34b

Also I just noticed back a few pages that Grimespace post a video of mike soldano running different tubes in a JCA50. Unfortunately, my connection is too slow to watch it at the moment.

What's up with that video?

Well either way, it sounds doable.

So you got a JCA22h?

No, I have a 20H. Going to start doing a few mods here and there to make it more "mine"

I did a few mods to a 22H and holy hell, it was not the same amp afterwards. Much tighter, fuller, screamier and pleasantly nasty.

[Tortuga]

Well I already ordered the Ruby EL34b

Also I just noticed back a few pages that Grimespace post a video of mike soldano running different tubes in a JCA50. Unfortunately, my connection is too slow to watch it at the moment.

What's up with that video?

Well either way, it sounds doable.

So you got a JCA22h?

That video just came out, so nobody's sure whether the transformers are same as what we have in our older heads. Bottom line was, Soldano stated that you could run pretty much anything up to KT88s with just a few resistor changes - at least on the new head he was working on. They were very specific in that they weren't advising anyone out there to perform any of the mods they were doing, even setting bias, which was done with an oscilloscope.

Which makes me think the Transformers are still the old parts.

RFPC had a few KT88 vids, but he took them out for some KT66s. I wonder if Doug notified him it may not be in his best interests for prolonged usage.

He did pull the 88's - and yes, I do recall him stating that JCA let him know it wasn't such a good idea

[mjtripper]

Hey Dudes...

Jay,
I actually blew the OT on my JCA100, I'm getting an "Upgraded SLO Spec" OT from Heyboer.
Turns out, they're about 30 miles away from me. $150. Custom wind, drop in.

I have a set of those and they are nice trannies, at least as good or better then the onetics. They are pretty close to me as well. I'm down in the Kalamazoo area, where are you?

[Motocooney]

I'm in Grand Rapids.
Do you play out at all?
We (Moto) haven't jammed out in Kzoo in a bit man. Cool town though.
Miss Club Soda for sure....

So you have the Heyboer OT and PT. Is this on a JCA amp?
What differences did you notice?

[Jay]

Hey Dudes...

Jay,
I actually blew the OT on my JCA100, I'm getting an "Upgraded SLO Spec" OT from Heyboer.
Turns out, they're about 30 miles away from me. $150. Custom wind, drop in.

I have a set of those and they are nice trannies, at least as good or better then the onetics. They are pretty close to me as well. I'm down in the Kalamazoo area, where are you?

Did the Heyboers drop right into the stock mounting locations?

[Motocooney]

Just in case anyone was wondering...replacement transformers are $25 shipped from Jet City lol

That seems crazy cheap to me. Even if they are junk.
Don't you think?

I also asked them about the el34 thing and haven't heard back yet.

[Motocooney]

Okay I got a reply from Jet City regarding el34 tubes with stock transformers in a jca100h.....

"Yes, you CAN. I don’t know the exact values, ok, cos I am not an engineer. But I have watched the Soldano himself do the EL34 mod and he just changed the screen grids and the bias. D.

GO Seahawks!"

[Jay]

Something like 1k to 1k5 would probably be a safe bet for the SGRs. For the bias, you will need to see what you get for a reading, but you will probably need to change the resistor. I just don't know where to start you off at the moment to get you a good range for both types of tubes. Then, jump pin one on the sockets to ground.

[overdrivenel34s]

I have a JCA2212C 20W 1x12 20watt combo. I had gotten it back on one of those stupid deals of the day.
I wasn't blown away by it and kinda disappointed with the clean tones but it gets some good crunch and hi gain tones. It does seem to take pedals well (the ones i've tried so far).

I have yet to open her up volume wise. The overdrive channel has lots of gain even with the gain knob set low you get significant drive. The gain on that channel is does get fizzy at lower volumes with any significant gain (can't comment on high volumes yet). Cutting treble and presence helps some but then the crunch channel ends out too dark...

[neilrocks25]

I have a JCA2212C 20W 1x12 20watt combo. I had gotten it back on one of those stupid deals of the day.
I wasn't blown away by it and kinda disappointed with the clean tones but it gets some good crunch and hi gain tones. It does seem to take pedals well (the ones i've tried so far).

I have yet to open her up volume wise. The overdrive channel has lots of gain even with the gain knob set low you get significant drive. The gain on that channel is does get fizzy at lower volumes with any significant gain (can't comment on high volumes yet). Cutting treble and presence helps some but then the crunch channel ends out too dark...

Step 1. Change the tubes, this is a must.
Step 2, turn it up
Step 3, cleans are for pussies
Step 4, look at some mods, the depth mod is a good one


What kid of sounds are you going for? Also try the EQ on 666 it works well.
And for cleans use the guitars volume it works better that way, when dialled into the amp it's a bit meh. Crunch then lower the volume on your guitar.

[Tortuga]

Step 1. Change the tubes, this is a must.
Step 2, turn it up
Step 3, cleans are for pussies
Step 4, look at some mods, the depth mod is a good one


What kid of sounds are you going for? Also try the EQ on 666 it works well.
And for cleans use the guitars volume it works better that way, when dialled into the amp it's a bit meh. Crunch then lower the volume on your guitar.

Don't forget - set the bias, and look into the slope resistor / tone stack voicing mod

[mean_charlie]

ok as for changing out my old stock tubes what would you all recommend i got the jca5212rc its a 2x12 200w combo amp i'm totally open to suggestions as tubes are not my area of expertise i studied electronics but mostly operational amp and digital circuitry so in the realm of tube i'm a novice i've played tube amps for aeons and i love the sound of the amp better than most but replacing the stock tube i dont know where to begin

[Tortuga]

ok as for changing out my old stock tubes what would you all recommend i got the jca5212rc its a 2x12 200w combo amp i'm totally open to suggestions as tubes are not my area of expertise i studied electronics but mostly operational amp and digital circuitry so in the realm of tube i'm a novice i've played tube amps for aeons and i love the sound of the amp better than most but replacing the stock tube i dont know where to begin

My advice is to contact one of the more reputable tube vendors (Eurotubes, ValveQueen, Tube Doctor, Tube Depot, The Tube Store, etc) and tell them what you're wanting to do. I bought a set of JJ tubes and a bias tester from Eurotubes, and have been really happy with them. Their support person gave me a lot of information as to what the bias should be set to (actually varies, based on what plate voltage your PT is supplying).

Note - I'm assuming you're familiar with circuit testing, based on your stated experience with electronics. That said, op amps and digital circuits don't run on the kind of juice your typical tube amp is running - something in the neighborhood of 400 volts. You have to exercise EXTREME caution when poking around inside the chassis, even when the thing is off and / or unplugged.

Getting a good set of starter tubes and setting your bias right will make a HUGE difference in how your amp sounds, and will establish a good baseline for other mods and trying out other tubes.

Oh, and one other thing - it'd sure help my tired old eyes and OCD if you'd try a little bit of punctuation & grammar in your posts - kinda hard to read a three line run-on sentence, eh?

[mjtripper]

Hey Dudes...

Jay,
I actually blew the OT on my JCA100, I'm getting an "Upgraded SLO Spec" OT from Heyboer.
Turns out, they're about 30 miles away from me. $150. Custom wind, drop in.

I have a set of those and they are nice trannies, at least as good or better then the onetics. They are pretty close to me as well. I'm down in the Kalamazoo area, where are you?

Did the Heyboers drop right into the stock mounting locations?

I didn't replace the jet city ones but used them for a from scratch build. I don't have two exact amps to compare them but have some very very similar builds and the heyboers seem a little more hi def then the stock ones. I can't tell the difference between the onetics and heyboers if that helps. The mounting holes ctc are:

PT: 4 1/2" x 3"
OT: 3 3/8" x 3"
choke: 3 3/8"

[mjtripper]

I'm in Grand Rapids.
Do you play out at all?
We (Moto) haven't jammed out in Kzoo in a bit man. Cool town though.
Miss Club Soda for sure....

So you have the Heyboer OT and PT. Is this on a JCA amp?
What differences did you notice?

Not anymore, life got in the way so I just jam with some friends once in a while or fill in on rhythm duties here and there. I spend most of my time tinkering with the amps these days. I put the heyboers in a full ground up build so can't a/b them with the jet cities right now but they seem to be a little more hi def then the stock jet city with more output and I can't tell the difference from the onetics and heyboers. I just sold my jca50 so right now all I have are a couple jca22 and couple pico valves I've been tinkering with and two sloclones one of which is close to stock but the other has been morphed into a modern modded marshall style build in the veins of uberschall, ktre, or vh4. If you are ever down in this neck of the woods you are welcome to check them out and we can compare notes. I keep trying to get up to GR because the guitar center up there just got in a herbert that I really want to check out as I've never had the chance to play one.

Yeah, I miss Soda also, that was a GREAT place. I got to see Prong there shortly before they closed up. Rick's was good back in the day but Soda ruled.

[Motocooney]

I jammed the Herbert at GC. It honestly didn't destroy me like I thought it would. Played through an orange 412. It seemed kind of bright and brittle almost. Of course I didn't turn it up either.
I'd take it if somebody wanted to give it to me:)

[Nova]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

[Jay]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

Have you ever soldered on PCBs before or had any electronics experience.

[mean_charlie]

Big thanks to you Grimespace. sorry about the punctuation, i'm terrible bout run on sentences.

I am very versed with most circuitry, tubes however is a new realm for me. I biased a few tubes back in the day in school, but that was the extent of my work with tubes. Never built any circuits around them or anything, and this was the mid nineties. so my question what kind of precautions should i take, besides the obvious risk of electrocution? I really dont want to burn up anything or screw the amp up beyond repair. So any Do's and Dont's of tube upgrades and biasing would be super appreciated.

[Nova]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

Have you ever soldered on PCBs before or had any electronics experience.

Nothing at all, but I'm trying to learn. Maybe I should start smaller? I bought a DS-1 specifically for modding. Maybe I should tackle that first?

[Jay]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

Have you ever soldered on PCBs before or had any electronics experience.

Nothing at all, but I'm trying to learn. Maybe I should start smaller? I bought a DS-1 specifically for modding. Maybe I should tackle that first?

Good idea! Check out some of the MonteAllums mods. He has a pretty comprehensive list of mods, and they all seem fairly easy.

It would be a bit disheartening if you accidentally melted or pulled up a PCB trace on the JCA. That said....the traces on the JCA boards are pretty tough.

Also, are you handy with a drill? Depending on where you want to mount the depth pot, you may need to make holes. Check out a few vids on soldering, too. It's not extremely difficult, but it's always good to see to get a few pointers here and there.

[Nova]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

Have you ever soldered on PCBs before or had any electronics experience.

Nothing at all, but I'm trying to learn. Maybe I should start smaller? I bought a DS-1 specifically for modding. Maybe I should tackle that first?

Good idea! Check out some of the MonteAllums mods. He has a pretty comprehensive list of mods, and they all seem fairly easy.

It would be a bit disheartening if you accidentally melted or pulled up a PCB trace on the JCA. That said....the traces on the JCA boards are pretty tough.

Also, are you handy with a drill? Depending on where you want to mount the depth pot, you may need to make holes. Check out a few vids on soldering, too. It's not extremely difficult, but it's always good to see to get a few pointers here and there.

Yep I can drill, and am pretty good at figuring things like this out, it just helps to have a somewhere from which to start. Thanks for the directions!

[Jay]

So I'm interested in doing the depth mod, and maybe a couple other basic mods. I heard about a mid boost switch that I would love to throw on. How difficult are these for someone who has ZERO knowledge about the inside of an amp?

Have you ever soldered on PCBs before or had any electronics experience.

Nothing at all, but I'm trying to learn. Maybe I should start smaller? I bought a DS-1 specifically for modding. Maybe I should tackle that first?

Good idea! Check out some of the MonteAllums mods. He has a pretty comprehensive list of mods, and they all seem fairly easy.

It would be a bit disheartening if you accidentally melted or pulled up a PCB trace on the JCA. That said....the traces on the JCA boards are pretty tough.

Also, are you handy with a drill? Depending on where you want to mount the depth pot, you may need to make holes. Check out a few vids on soldering, too. It's not extremely difficult, but it's always good to see to get a few pointers here and there.

Yep I can drill, and am pretty good at figuring things like this out, it just helps to have a somewhere from which to start. Thanks for the directions!

Just let us know when you want to dig in. I'm not doubting your abilities. I would just like to see that you have a good experience when it's all done.