JCA22H and so it begins!

[dave_mc]

^ nice :D

[Nadz1lla]

Clips? 

[Dmoney]

I just tried to make a video using my macbook and the built in camera import thing in imovie. the audio however was terrible. All warbled and stuff. I'd like to make a video so people can see what switches do what. Just got to figure out a good way to do it that doesn't require me going out and buying stuff.

[Dmoney]

This gives you a vague idea.
I managed to use a little usb audio in/out on my macbook to take the input from my hotplate and run it into garageband where I could apply a cab sim, then use the monitoring output to feed the built-in audio input so I could record the audio while filming in imovie. bit of pain. Also meant I couldn't hear what the recording was like while playing. So I'm just looking at the audio level in garageband to try and even out volume between changing channels.

Most mods effect the crunch channel. Switches left to right are...
Channel switch (under the jack)
Clean/Crunch switch
Bright switch for the Clean/Crunch channel. Switch in up position is Bright On.
SRV mod (mid scoop with boosted lows and highs). This switch pops when I turn it on but that is expected.
Bright cap switch for the Overdrive channel. Disconnects the bright cap when turned on.

The switches in the down position are considered in 'normal' mode. Up is 'On'. 

It hasn't come out THAT well, but it gives you an indication of whats up. I noticed I forgot to turn down the depth control at one point. urgh. It isn't the best indication of my playing either! Honest!

http://www.youtube.com/watch?v=PGkOpR8AkCA

[Kiichi]

The more I read about these the more I am tempted. Also seems like a great way to make the jump from pedal building to amp modding.

Please do tell more about how effective and easy the mods were. I assume the amp is damn good value for money even without mods. With them it is insane even or what?

I think I might save towards the 50W combo and try to mod the sh*te outa that one...

[Toe-Knee]

This gives you a vague idea.
I managed to use a little usb audio in/out on my macbook to take the input from my hotplate and run it into garageband where I could apply a cab sim, then use the monitoring output to feed the built-in audio input so I could record the audio while filming in imovie. bit of pain. Also meant I couldn't hear what the recording was like while playing. So I'm just looking at the audio level in garageband to try and even out volume between changing channels.

Most mods effect the crunch channel. Switches left to right are...
Channel switch (under the jack)
Clean/Crunch switch
Bright switch for the Clean/Crunch channel. Switch in up position is Bright On.
SRV mod (mid scoop with boosted lows and highs). This switch pops when I turn it on but that is expected.
Bright cap switch for the Overdrive channel. Disconnects the bright cap when turned on.

The switches in the down position are considered in 'normal' mode. Up is 'On'. 

It hasn't come out THAT well, but it gives you an indication of whats up. I noticed I forgot to turn down the depth control at one point. urgh. It isn't the best indication of my playing either! Honest!

http://www.youtube.com/watch?v=PGkOpR8AkCA

It says the video is private!

[Dmoney]

Ah!
what about now?

EDIT: listening to that video on my laptop the day after doing it is pretty embarrassing

[fps_dean]

Those generally unbranded Chinese tubes are usually pretty terrible.  Some of them have a lot of gain so some people like them for that reason, but the tone quality is still downright awful!

For new tubes that are pretty gainy and fat sounding and don't cost an arm and a leg, I like the Electro-Harmonix 12AX7s a lot.  Much better than the JJs which are very thin.  Of course now there's Gold Lions and Mullards and a lot of other stuff to choose from as well.  I also have some German RFTs and Amperex that I like a lot.

[Dmoney]

I that clip im using JJ ECC83S'.

I like them. I feel they offer a good compromise between being mechanically robust and sounding ok.
I have some RFT's, Tungsrams, EHs, Sovteks, a Brimar, a Mullard. A couple different 5751's (JJ, Philips, Sovtek).

I like a nice 5751.

I've kept the chinese valves to one side. In any case, this amp is still bright but not as fizzy up top as before. To be fair though I've made enough changes to the amp to make the original valves sound different again. So a straight valve swap as a test would need to be compared in the amp as it is now. I haven't done that.

[Kiichi]

In my TT hardwired the stock valves were not too bad at all, but I still replaced them with a TAD STR set for the power section and a JJ in V1 + a Tung Sol in V2.

While that is always subject to change (I have not even tried Mullards yet in anything but my tube mic) this really appeals to me. I cannot see though how someone would find the JJs to be "thing". I found them to be quite thick, dark and roary, which I like in V1, but I need Tung Sol in V2 to get that something back in there.

I am currently fiddling again since I just got a boob tube also, but even with the TS and my Klone (yeah I freaking love Johnīs work) adding high end and overtones to the JJ I still sometimes feel that I need more openness. Might just be that I am living in student housing and canīt remotly crank it (and the Weber Mini Mass does only so much...it does change the tone after all)), but there is something missing.

Might get another TS or TAD or something for V1 or 2 and if I get lucky a set of Mullard power tubes some time.



Back from the tubes and on topic: I have read this into your posts so far, but do you actually think that the JCA is good value for money? How much does is improve with mods? How hard to do are the mods that make the difference?

Anyone know if the combos are good also? How is the cab and the speakers? Really looking at the 50 combo right now...

[fps_dean]

I that clip im using JJ ECC83S'.

I like them. I feel they offer a good compromise between being mechanically robust and sounding ok.
I have some RFT's, Tungsrams, EHs, Sovteks, a Brimar, a Mullard. A couple different 5751's (JJ, Philips, Sovtek).

I like a nice 5751.

I've kept the chinese valves to one side. In any case, this amp is still bright but not as fizzy up top as before. To be fair though I've made enough changes to the amp to make the original valves sound different again. So a straight valve swap as a test would need to be compared in the amp as it is now. I haven't done that.

I've done several A/B tests myself...

I guess some JJ's are okay -- they usually don't go microphonic for a long time and have very low noise.   I prefer them to Sovteks and Svetlanas (for preamp tubes) and Eis (because they're very bad for microphonics).

When I AB/D several JJs with a EH though, the difference in sound quality was pretty amazing! And when I compared the EH to the Amperex, the sound got even fatter much in the same effect.

The Amperex could be super compressed in higher gain amps where I thought the EH is pretty safe for any application.  RFTs are also a safe bet with any amp too, especially the German ones.

I don't have the knowledge to do my own mods or anything, but I'm the sort of hands on person who's always curious about the differences between every little thing...  I found myself buying preamp tubes because those are easy to swap out just to test them out for differences in tone.

[fps_dean]

My original point is that the Chinese preamp tubes really are generally pretty terrible.  I don't think it's ever worth the extra gain...

[Dmoney]

I might try one of the chinese valves in my SLO. They are the first Chinese tubes I've had, although they do look very similar to some Ruby 12AX7's I have. I've never read much good about them.

The long plate JJ ECC803S (I think it's the 803S?) sounds pretty good. I didn't like the RFT so much in my SLO V1 but it wasn't bad, I just prefered the Tungsram. The Ei's I had sucked too. The Mullard I have sounds rubbish in everything. Just goes to show you what a name alone is worth.

Sometimes I swap em around and find a new combo I like. I keep meaning to try the Tung Sol Reissue.

The JCA is very good value for money. My JCA22H could do clean unmodded if you cranked the Crunch master up and used the preamp gain knob as a volume. I really like the depth mod. The SRV style mod I did is really cool if you like cleans. It fills out the low and and adds some sparkle. It's decent. That said, I wouldn't say they need to be modded. The lead circuit in there is very very similar to the SLO, which really set the benchmark for high gain tones. There are loads of mods out there. I could add a voicing switch to the tone stack to change the mid character. That is popular. I also would like to try adding a tone stack and cutting down the channel bleed. Channel bleed seems to be a feature of some soldano designs. The parts in them seem good and the PCB's look to be very similar in layout to what you get in a USA made Soldano

[fps_dean]

Ruby tubes are generally branded tubes, they can be anything.  I have some Rubys that are Sovtek 12AX7LPS, a JJ ECC83S and a JJ ECC803S and while I was in the store I saw other tubes branded as Ruby too.

I'm really not familiar with Jet City Amplification to be honest but they seem like they're definitely a great buy for the buck, if nothing else.

[Dmoney]

Ah! I never spotted that, I do tend to ignore Ruby though. The times when I've ONLY been able to buy Ruby valves in a shop, I generally avoided it because it's been expensive. Like when people try and sell you Mesa 6L6's for stupid money. The ones I have are definitely closest to these chinese jobs. Very similar.

The Jet City stuff is generally licensed Soldano designs though the Picovalve was a THD Univalve affair. The Retro Tubes come from another guy, Doug Roberts. They make a bunch of gadgets but the main amps that have lasted have been the JCA20 (Soldano Atomic 16 kind of thing) and the JCA50/100 (Like a Soldano Hot Rod). The JCA22H is a bit different in that it has the Hot Rod style preamp but the power stage is EL84. It has has a post master loop which im not sure the others do. Soldano currently makes a Hot Rod 25, which i think is the Hot Rod 50 on a lower B+. I think, it even uses the 50watt transformers to a degree and has a choke as standard. It also runs 5881's and not EL84's.

A Soldano Hot Rod+ 100 is probably around the Ģ2K mark now. The JCA stuff is built in the far east with different parts, but I don't think the parts are bad. The resistors are pretty beefy, probably 1watt at least. The filter caps are 105degree rated in place so should probably have a long life. Build quality isn't as high as the US Soldano stuff and the circuits differ slightly, but a few resistor changes can sort you out if you want to be anal. The design quality is better than Bugera and better than a lot of amps up the Ģ900 mark I'd say. I'd rather take one of these over a DSL.