Bare Knuckle Pickups Forum
Forum Ringside => Guitars, Amps and Effects => Topic started by: Nadz1lla on February 21, 2013, 05:12:43 PM
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WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!
My first ever all-tube amp! Saturday is Cab hunting day, going to try out a Jet City 2x12 hopefully. They're going silly-cheap on Thomann at the moment.
So this is a modified JCA20H, I don't have a cab in the house at the moment so I've not been able to actually hook it up and try it out, but structurally and aesthetically it looks solid and fairly unblemished. A few scratches on the corner protectors but that's to be expected.
Here's some of the blurb from the original ebay listing:
"This amp has been modded professionally to provide the following features;
Clean channel + Overdrive /Distoration Channel- making it a 2 channel amp + Boot option for each channel. The secoundchannel being the overdrive channel producing great sounds FROM MILD OVERDRIVE TO FULL SATURATED DISTORTION WITH GREAT CLARITY AND DEFINITION.
Effects Loop.
Variable boost control for both channels.
Also included is a custom adapted footswitch which gives the ability to do the following:-
A/B with another amp.
Channel changing on A and B amps.
Volume boost on both Jet City channels.
The mods done to it make this an extremely versatile amp using the footswitch even for A/B'd with another amp."
The attenuator that the guy chucked in free looks a bit ropey, apparently it's by a proper make, but this looks like it was a "starting out" model, probably made in the guys bedroom, as the company logo is on a pretty cheap-looking sticker on the front. But hey, it's an attenuator, which is great, because I fully intended to buy one anyway. :D
Pretty stoked right now, just hope it works properly, hah! Won't know until Saturday, but until then, this is one happy chap signing off! :lol:
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That sucks you can't use it yet, it must be agonizing!
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It totally is, hah! It's excruciating! I have my mate's amp here that has a 12" that I could, in theory, test it on, but the speaker connectors are a bit dodgy and it shocked the guitar player from my old band at a gig, so I don't want to kill myself trying, think I'll leave it until the weekend. :lol:
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Congrats, they sound nice for the price!
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Another congrats. Great amp for the price and I can only asume that the modded version is even cooler.
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Cool, sounds like a good deal! Where abouts are you? If you don't get sorted quickly with your cab I have a Marshall 1 x 12 you can borrow for a week or 2 if it helps? I'm in West Mids. Hope it all works out though. Congrats.
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sweet :D
that's annoying that you have no cab... i remember when i got my first tube amp the same thing happened, the amp turned up about a week before the cab. that wasn't much fun :lol:
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Enjoy!
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BOOM!
Manson's had one Jet City cab left. Cheapest cab in the store and by far the best sounding for this amp, so JC really know how to pair their heads and speakers. They almost matched the Thomann price, too, so I bit the bullet and paid the £30 difference for convenience to take it away today.
SO happy right now, my first tube-amp and I'm loving it. Going to set it all up right now with my Bad Monkey and tweak the tone. :D
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Looking good!
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Yeah, looks like a fine set!
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nice :D
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Cheers guys. :D
I just need to finish this soundproof partition I'm making for the doorway to the kitchen so I can start recording out there at a decent volume, heh. Then I shall be chucking clips up. :D
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Cheers guys. :D
I just need to finish this soundproof partition I'm making for the doorway to the kitchen so I can start recording out there at a decent volume, heh. Then I shall be chucking clips up. :D
Can't wait!
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Oh - I saw that on ebay and was tempted by it. Did wonder how well the mods had been executed though...
Look forward to your review
I have the combo version , but it may be that it has less gain as it is the Soldano Atomic 16 circuit in that one.
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^ yeah I think so. i've only tried the 50 i have, but i think the 20 has less gain. they brought out the 22 more recently which (i think) is the higher gain preamp of the higher wattage heads coupled with the ~20 watt EL84 power section.
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Aye he's not been able to tell me who did it, yet, which makes me a little bit "hmmm...", but I've not even tried the A/Bing, just been using it as a normal amp. The two channels work well, though.
I have a feeling I will be sending this to someone in the future to see about taking out some of the modding and replacing it with something I'll actually use more, maybe. We'll see.
After a bit more playing, I might want to look at other tube options. It's SO close to "my" sound but not quiiiiiiiite there yet. I have an EQ pedal to try in the chain and my noise suppressor with it's unforeseen but rather nice tonal side-effect. I have a lot of playing around and experimenting to do before I go thinking about mods. :lol:
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Aye he's not been able to tell me who did it, yet, which makes me a little bit "hmmm...", but I've not even tried the A/Bing, just been using it as a normal amp. The two channels work well, though.
I have a feeling I will be sending this to someone in the future to see about taking out some of the modding and replacing it with something I'll actually use more, maybe. We'll see.
After a bit more playing, I might want to look at other tube options. It's SO close to "my" sound but not quiiiiiiiite there yet. I have an EQ pedal to try in the chain and my noise suppressor with it's unforeseen but rather nice tonal side-effect. I have a lot of playing around and experimenting to do before I go thinking about mods. :lol:
What don't you like about the current mods?
Regarding valves what are in it currently? I imagine a set of tungsol 12ax7s in the preamp will push it closer to suiting your style.
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I don't dislike the mods as such, just that whilst it's nifty, I don't think I'd ever use the A/B mod. Just thinking if something else could go in there and make use of the changes to the chassis etc then it might be worth considering what else is out there. I don't have anything particular in mind at the moment, though.
Not sure what's currently in there in terms of valves, when I get the time I'll open her up and have a good old gander. Working all the hours of the day pretty much this week, heh. Will try to do it at the weekend. :)
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post a gut pic. g'waaaaannn!
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So I managed to get some time to take the thing apart for you gut-pic lovers. I haven't got the first clue about which parts you guys find most interesting, so I took close-ups of all of the inside, heh.
Behold!
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...
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...
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Aaaaand last one :lol:
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THREADOMANCY!!!
Been playing this amp for a while now, and I kind of feel that the high-gain could do with some more grunt. There's a bit too much "fizz" and not enough "guts", if you know what I mean?
Regarding valves what are in it currently? I imagine a set of tungsol 12ax7s in the preamp will push it closer to suiting your style.
I was wondering how I would go about learning which valves create certain sounds, actually. I had a look on t'interwebs for those Tungsol, and they were quite cheap compared to a lot of other valves that were on offer in the same section. What options do you reckon I have in this department, and are valves easy to take out and re-install?
:)
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THREADOMANCY!!!
Been playing this amp for a while now, and I kind of feel that the high-gain could do with some more grunt. There's a bit too much "fizz" and not enough "guts", if you know what I mean?
Regarding valves what are in it currently? I imagine a set of tungsol 12ax7s in the preamp will push it closer to suiting your style.
I was wondering how I would go about learning which valves create certain sounds, actually. I had a look on t'interwebs for those Tungsol, and they were quite cheap compared to a lot of other valves that were on offer in the same section. What options do you reckon I have in this department, and are valves easy to take out and re-install?
:)
The preamp valves you can just pull out and swap. The power amp valves will need rebiasing.
I am quite fond of tungsol RI in v1 then JJ ECC83s in the other spots.
Im not sure what to recommend for the power amp as i dont have much experience with el84/6v6 (not sure whats in the jca20)
the JJs will definitely give you more 'guts' the tungsols are pretty high gain and can be bright which is why i only use them in v1.
If you dont like fizz avoid Electro harmonix 12ax7 like the plague. Theyre really bright and aggressive in the high end. They can be great in the right amp though
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you could also try a tubescreamer-style od pedal, or try different speakers (i like eminence v12s with my 50 watt jet city).
I'm guessing JJs would help on the valve front, but that's only from my experience with them in other amps.
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Cheers guys! Very helpful.
Toe-Knee - thanks I'll have a gander at getting some of those. As for re-biasing, I'm guessing I'd have to drop it into an amp specialist to get that done? I'm handy with building and fixing stuff, but I am guessing "re-biasing" is a little more specialist than taking one thing out and putting another thing in? Also V1 = Clean and V2 = Crunch?
Dave - I am currently using a Bad Monkey, which I had researched a lot prior to buying. It seemed to come really close in most of the video comparisons I watched, and actually preferred the tone it gave over the "real" TS in one of the Tone King's vids. I do like what it adds to my tone, just the right amount of tweaking on the pedal side of things I think, heh.
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To be honest if you do your research regarding your particular amp model and read some safety information biasing an amp is quicker and easier than changing strings on a guitar.
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As for re-biasing, I'm guessing I'd have to drop it into an amp specialist to get that done?
Depends on the amp and your own technical skills (and tooling). Some amps don't need biasing at all since the circuit takes care of it ("cathode-biased" aka "self-biased" amps like the Vox AC30 or Tweed Deluxe), some amps have a "bias point" (where you can get a reading of the bias voltage) and a trim-pot to adjust it so all you need is a multimeter, a screwdriver and a few advises from someone more knowledgeable, and finally a lot of amps don't have a bias point or trim-pot in which case, well, getting your amp to a real amp tech might indeed be the simplest (and safest) solution :lol:
wrt/ your own amp it seems that it has a trim-pot but no bias point so if you have a good multimeter (one that can takes 400+VDC) and feel confortable working with lethal DC voltages here's a starter:
http://www.youtube.com/watch?v=V4T83PgEIhc (http://www.youtube.com/watch?v=V4T83PgEIhc)
Also V1 = Clean and V2 = Crunch?
Here again it depends on the amp. In your case V1 is used for the first two gain stages (12Awhatever7 are double triodes - 2 gain stages in one bottle) so it's a very important part of your tone (everything else will reamplify what comes out of it) and it needs to be a very silent (no hum, no microphonics) tube. V2 add some more gain and builds the preamp's distortion on what was provided by V1. Now it's not a channel switcher amp and both V1 and V2 are always on , so you can't really think in terms of "V1 clean / V2 crunch" (and FWIW even for simple channel switchers like the HRDx, Classic30 etc, V1 is still always on, you just have the option to switch V2 in and out of the circuit).
(disclaimer: overly simplified answer - I failed to find a decent schematic for the JCA20 and I'm not an amp tech).
[edit]
Rereading your very first post I see yours has been modded for a "clean / crunch " operation. I can't tell for sure what the exact mod is but I suspect it mostly switches V2 out of the circuit like for most regular channel switchers (cf above), so you would have clean -> V1 only, crunch -> V1+V2.
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To be honest if you do your research regarding your particular amp model and read some safety information biasing an amp is quicker and easier than changing strings on a guitar.
Well, at least there's no lethal DC voltage involved in changing strings :lol:
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As for re-biasing, I'm guessing I'd have to drop it into an amp specialist to get that done?
Depends on the amp and your own technical skills (and tooling). Some amps don't need biasing at all since the circuit takes care of it ("cathode-biased" aka "self-biased" amps like the Vox AC30 or Tweed Deluxe), some amps have a "bias point" (where you can get a reading of the bias voltage) and a trim-pot to adjust it so all you need is a multimeter, a screwdriver and a few advises from someone more knowledgeable, and finally a lot of amps don't have a bias point or trim-pot in which case, well, getting your amp to a real amp tech might indeed be the simplest (and safest) solution :lol:
wrt/ your own amp it seems that it has a trim-pot but no bias point so if you have a good multimeter (one that can takes 400+VDC) and feel confortable working with lethal DC voltages here's a starter:
http://www.youtube.com/watch?v=V4T83PgEIhc (http://www.youtube.com/watch?v=V4T83PgEIhc)
Also V1 = Clean and V2 = Crunch?
Here again it depends on the amp. In your case V1 is used for the first two gain stages (12Awhatever7 are double triodes - 2 gain stages in one bottle) so it's a very important part of your tone (everything else will reamplify what comes out of it) and it needs to be a very silent (no hum, no microphonics) tube. V2 add some more gain and builds the preamp's distortion on what was provided by V1. Now it's not a channel switcher amp and both V1 and V2 are always on , so you can't really think in terms of "V1 clean / V2 crunch" (and FWIW even for simple channel switchers like the HRDx, Classic30 etc, V1 is still always on, you just have the option to switch V2 in and out of the circuit).
(disclaimer: overly simplified answer - I failed to find a decent schematic for the JCA20 and I'm not an amp tech).
To be honest if you do your research regarding your particular amp model and read some safety information biasing an amp is quicker and easier than changing strings on a guitar.
Well, at least there's no lethal DC voltage involved in changing strings :lol:
That is a very good point! It's why i also mentioned to look up required safety info.
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I am currently using a Bad Monkey
FWIW I used a bad monkey for a while, great pedal but definitely a bit of fizz added by the pedal when boosting a hi gain amp. YMMV I upgraded to an OD808 and have never looked back.
Hard to appreciate the differences until you do a shootout in person I find. If you want to stick with the digitech I'd be very conservative with the treble knob
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Thanks for all the info, guys, really helps!
I can usually fix things myself, but when electricity is involved I feel a lot safer handing it over to an amp tech if possible. Just so happens we have a fairly good one in the area who Manson's send people to all the time. He serviced an old Marshall Valvestate I had once before I sold it, and when it came back to me it sounded so much better that I almost didn't sell it, heh. I had to in the end as we lived in a tiny flat and I had my Pod XT, so space took priority over the amp. >_<
I need to try me an OD808, heard a lot of good things. I got the Monkey because it was so cheap, but always open to other options.
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Thanks for all the info, guys, really helps!
I can usually fix things myself, but when electricity is involved I feel a lot safer handing it over to an amp tech if possible. Just so happens we have a fairly good one in the area who Manson's send people to all the time. He serviced an old Marshall Valvestate I had once before I sold it, and when it came back to me it sounded so much better that I almost didn't sell it, heh. I had to in the end as we lived in a tiny flat and I had my Pod XT, so space took priority over the amp. >_<
I need to try me an OD808, heard a lot of good things. I got the Monkey because it was so cheap, but always open to other options.
I recently built an od808 and they really are perfect for metal. As is the od820
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Dave - I am currently using a Bad Monkey, which I had researched a lot prior to buying. It seemed to come really close in most of the video comparisons I watched, and actually preferred the tone it gave over the "real" TS in one of the Tone King's vids. I do like what it adds to my tone, just the right amount of tweaking on the pedal side of things I think, heh.
ah right no worries, if you already have a BM it should be fine. Never tried one, but from what i hear it's more or less a tubescreamer with a bass knob. i'd swap speakers long before getting a "better" tubescreamer, but that's just me. i only tried the stock jet city speakers for a couple of minutes (as i already had the v12s and couldn't wait to get them in :lol: ) but they seemed a bit brighter/fizzier than the v12s. Granted breaking in should help that a lot, but even out of the box the v12s tamed the jet city down a good bit.
Well, at least there's no lethal DC voltage involved in changing strings :lol:
you haven't seen me changing strings :oops:
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I can usually fix things myself, but when electricity is involved I feel a lot safer handing it over to an amp tech if possible.
Well, it ain't rocket science neither and wrt/ high voltage it's just a matter of learning and applying the safety rules. To-knee's suggestion to google for more infos about biasing this particular amp is a good one, then you'll see if you feel you could do it or rather leave it to someone else.
wrt/ OD pedals, the BM is indeed Yet Another Variation on the ubiquitous Tube Screamer circuit, so if doesn't work for your amp and guitar you may want to first try another kind of OD circuit. FWIW the TS doesn't really work for me on my amp's SLO-like channel (tried both my old TS9 and my homemade TS808), the Dano CTO1 (Cochran Timmy copy) is a way better match (not that this channel needs any more gain...).
Well, at least there's no lethal DC voltage involved in changing strings :lol:
you haven't seen me changing strings :oops:
High tension has proved be lethal for guitar strings too, indeed :mrgreen:
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Just watched that video.... yeah... I'll be giving that to someone else to do. :?
I have a benign tremor which makes doing anything where you have to keep a steady hand very interesting, to say the least. I love to paint miniatures, but if you get a bad tremor, the worst case scenario is you have to re-paint that part. When an electrical current is concerned, I think it best to give that task to someone with a more reliable set of digits... :lol:
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High tension has proved be lethal for guitar strings too, indeed :mrgreen:
excellent :lol:
i've used the dano timmy copy too with my jet city and also the joyo ts copy. timmy is a lot more transparent, ts is middier. just depends on what you want. I tend to use the timmy as my always-on boost for rhythm tones and the ts for leads. but as you said, the jet city has a ton of preamp gain and it's not like it "needs" a boost.