howling hound
2 posts
Dec 22, 2009
7:43 PM
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I just bought a Kustom tube 12,has anyone ever dealt with these before , its from what I have been reading you want a tube amp for these dirty sounds but its tube preamp is this what I need for that dirty sound from an amp
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Hobostubs Ashlock
209 posts
Dec 22, 2009
8:06 PM
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i got a kustom12a i think its not bad for the money i have it hooked up with a fender 15r dual amp setup,but the fender sucks by itself to crispy but works good with the kustom.On the other hand the Kustom aint bad by itself.I havnt tried a lot of amps for harp but there nice priced and you can definetly get a better tone than the fender15r ive thought about switching out the pre amp tube to a different one but im not in a hurry
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wheezer
131 posts
Dec 23, 2009
2:31 AM
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I had a Kustom Tube 12. At the time I bought it, about 7 years ago, it was the best by far cheap amp for harp I could find. It has always been 100% reliable.
If you find feedback a problem (depends on the mic. you are using) you may like to try a 12at7 tube instead of the 12ax7.
My Kustom is now owned by John O'Leary (Savoy Brown)
who, like Hobostubs, uses it as a pre-amp and utilises
the line out to connect it to his Crate.
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Hobostubs Ashlock
212 posts
Dec 23, 2009
2:44 AM
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I Was running it like that though my line out into the fender and it has a awsome sound but was scared to really crank it the lower end was so deep that i was afraid i might hurt it.And the fender needed some low end But. here lately i have a Y cable spit the signal from a effects peddal that is just there to spit the signal turned off.into both amps,Not as much botttom end but still nice fatter sound than the fender alone had but i feel like i can push it louder and not run into problems.But i havent played live with the setup sence i got it.But big open mic party New year eve just might have to test her out.
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LIP RIPPER
157 posts
Dec 23, 2009
3:52 AM
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I had one and didn't care for it. I thought it was ok until I restored a Gibson Skylark. Sold that bitch in a hurry after that. I have since bought the Epi Valve Jr and I like it better than I did the Kustom as well.
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Hobostubs Ashlock
214 posts
Dec 23, 2009
4:08 AM
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yea ive heard alot about the Jr being a good amp i got the Kustom on ebay allmost new for 60$ didnt have a clue as to haow it might sound for harp but it had a tube preamp and was in my price range,i really like it though most time i play it alone around the house not have to hook up 2 amps and the Kustom does the job fine in conparrison to the fender 15r by its self.Dont get me wrong there not gona compare to a nice harp built amp,but im a broke man and for 60$ i cant beat it no how.Im wanting to change out the preamp tube ive heard a lot of people suggest it but not sure which tube .im wanting to say ive heard a
12u works good,But Wheezer said a 12at7 i know nothing about tubes any help as to which is better and why would help out alot thanks
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Ray
83 posts
Dec 23, 2009
5:05 AM
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I would change the 12ax7 to a 12au7. You can crank amp up more before feedback. I think it helps the tone a little also.
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Kingley
560 posts
Dec 23, 2009
5:56 AM
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I would only change the 12AX7 to a 12AY7.
If you use a 12AU7 you'll cut the liveliness of the amp too much and if you use a 12AT7 it'll most probably still feedback too early.
Last Edited by on Dec 23, 2009 5:56 AM
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Ray
84 posts
Dec 23, 2009
8:07 AM
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Best advice would be to buy an AT, AY and AU. Try them to see which you like best and sell the ones you don't use on ebay. Thats the ONLY way you will know for sure.
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Rick Davis
31 posts
Dec 23, 2009
8:51 AM
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Ray, I would avoid using the 12AT7 in the preamp seciton of this amp. It is normally used as a phase inverter or reverb driver. As a tone generator I think it sounds thin and shrill. It also draws a LOT more current than the other members of the 12A family of tubes. It was meant for VHF circuits like TV tuners, not audio preamps.
I prefer the 5751 tube when looking for a moderate reduction in gain factor. It is a perfect swap for stock 12AX7 tubes, with no compatibility issues.
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-Rick Davis
Blues Harp Amps Blog
Roadhouse Joe Blues Band
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MrVerylongusername
720 posts
Dec 23, 2009
9:01 AM
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Sorry Ray, but I'm with Kingley. The 12au7 only has a gain factor of just under 20%, you'll struggle to get any preamp clipping with that. True you'll have no feedback, but you'll have a totally clean sound that defies the point of have a tube preamp.
The 12at7 has a gain factor of 60%, you'll probably not notice much change in the gain before feedback.
The 12ay7 is in the middle - 40% of the gain of a 12ax7 - it's a good compromise and from personal experience in 4 different valve amps (1W, 5W, 30W and 40W) is the only one I'd recommend.
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Bluzdude46
339 posts
Dec 23, 2009
9:31 AM
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Depends how many pre amp stages the amp has. If it has more then one then combining a 12au7 with a 12ay or 12ax works. For single stage preamps the 12au doesn't have enough balls. In the Bassman I use V1-12au7 V2-12ay7 v3-12ax7 and it gives me the whole world of tone and punch I need.
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Hobostubs Ashlock
216 posts
Dec 23, 2009
10:23 AM
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wow theres a lot to think about on which preamp tubes if i had the extra money rays idea sounded good
Last Edited by on Dec 23, 2009 10:25 AM
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congaron
358 posts
Dec 23, 2009
10:27 AM
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I second the 5751. My preferred tube in the valve junior, but the more I play, the less it matters to me. I can use a 12ax7 without feedback issues now. I also use a pretty feedback resistant mic.
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Kingley
565 posts
Dec 23, 2009
11:16 AM
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Bluzedude is right it does depend on the type of preamp stage.
However when I owned a Fender '59 Bassman LTD, I used 12AY7, 12AX7, 12AX7 as that is what the original Fender '59 Bassman tube set up was. I never had feedback problems with that set up.
Of course mic choice, cupping technique, amp placement, stage volume, monitors, room size, etc. Can all affect the sound and feedback level of any amp as well.
Last Edited by on Dec 23, 2009 11:24 AM
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MrVerylongusername
722 posts
Dec 23, 2009
1:31 PM
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I've been doing a little reading about the Kustom 12. According to a reviewer on harmony central the single tube only drives the clean channel's preamp. The drive channel is solid state.
Now I'm not sure if lowering the tube gain is going to have any benefit; certainly not if you're using the drive channel.
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Hobostubs Ashlock
218 posts
Dec 23, 2009
1:51 PM
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i use the clean channel most times with it.My green bullet gives me enough of a overdrive,but then again i kinda like just a little bit of distortion the way i see it its a harp not a les paul lol
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howling hound
3 posts
Dec 23, 2009
2:03 PM
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any good sites to buy the tubes
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LIP RIPPER
158 posts
Dec 23, 2009
2:47 PM
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Vacuumtubes.net is a good site. I tried all of the afore mentioned tubes and the amp just didn't have it man. Sell it!
LR
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MrVerylongusername
723 posts
Dec 23, 2009
2:57 PM
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Leave it as a 12ax7 (although you might want to swap the crappy stock one for a decent brand) any lower gain and you'll lose the bit of crunch that you have.
There's no point in doing a tube swap.
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Hobostubs Ashlock
219 posts
Dec 23, 2009
3:11 PM
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hell only paid 60$ ebay for mine and i wouldnt take 120$ for it maybe i guess i got a good one cause it aint that bad with stock preamp tubes,a lot nicer than my fender 15r but then again that aint a harp amp either,but the Kustom has a tone that im happy with.and find a harp amp that cost the price of a harmonica is hard to find,If i was back to work i would check into nice harp amps that cost 500$ or more but hey i play poker as much as a harp you do the math lol
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MrVerylongusername
724 posts
Dec 23, 2009
5:47 PM
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Look guys! I don't want to get all stroppy, but read the thread!!!
THERE IS NO POINT SWAPPING THE TUBE FOR ANYTHING!...
because the tube only drives the clean channel. Presumably it is there to give the clean channel a nice tubey warmth. The drive channel is 100% solid state; it has nothing to do with the tube. A tube swap will not improve the driven sound at all. I'm not saying the drive channel sucks or that solid state is bad, just that the tube has nothing to do with it
If you lower the gain factor in the clean channel, you're just going to reduce the volume and what little coloration the tube adds. Pointless and a waste of money.
Last Edited by on Dec 23, 2009 5:54 PM
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Hobostubs Ashlock
221 posts
Dec 23, 2009
11:04 PM
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couldnt you use the clean channel with a overdrive peddal to get use of the tube if the clean channel is the only one using the preamp tube
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Bluzdude46
342 posts
Dec 24, 2009
9:09 AM
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the overdrive pedal is solid state, yes? I think the whole point gets missed. Clean channel or not, an overdriven 12ax7 tube will still distort, or am I missing something here?
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Rick Davis
35 posts
Dec 24, 2009
9:17 AM
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MVLUN- I doubt the drive channel will be harp-friendly. Drive channels on small guitar amps often feed back like a screaming banshee.
A harp player should switch off all Boost/FAT/Drive switches, and avoid high gain channels. They are evil for harp.
----------
-Rick Davis
Blues Harp Amps Blog
Roadhouse Joe Blues Band
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Kingley
572 posts
Dec 24, 2009
9:21 AM
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You are correct Bluzdude.
The Kustom Tube 12 is a one channel amp and has a gain boost switch which is powered by Solid State. In most scenarios that feature would be almost useless to a harmonica player. That is why you would play in the "clean" channel and overdrive the tube that way.
In an amp of that size (12 watts) it would overdrive extremely easily with a Hi-Z mic. But the tone of that gain would most likely be harsh and nasty and highly susceptible to feedback. That is why it should be lowered to a 12AY7.
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congaron
359 posts
Dec 24, 2009
10:08 AM
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If the tube preamp stage will be used with a microphone and it is a single 12ax7 stage...clean or otherwise...the 5751 is a tube that is designed to be ruggedized and reduce microphonics in military applications...so it is a worthwile swap if you plan to use the tube stage ever with your microphone....reduced microphonics=higher gain before feedback (gbf).
I honestly don't know the particulars of the tube stage in the kustom amp, as to whether or not the "gain boost" switch comes in before or after the tube, or bypasses it altogether. I DO know that a solid state gain boosting device like a digitech modeler or even the analog preamp stages of my behringer 100 watt amp can give you fantastic sound when introduced before the tube stage. I do this all the time with my valve junior. There is every imaginable harp sound in that little 5 watt head when combined with either of those two ss devices. Classic chicago dirt to crunchy, to trumpet clean, to sax simulation, to actual harmonica by the campfire. The behringer preamp is analog and also sounds amazing into my valve junior on guitar, simulating mesa boogie, fender or marshall sounds to a tee with the little tube amp. Better than with the ss 100 watt stereo amp it's built into....which is pretty darned good too.
Point is, lower the microphonics if you plan to use the tube stage at all with a mic. Perfect your technique and you will be able to play your sound into a beta 57 and a ss PA system or keyboard amp....as far as the audience is concerned. They want right notes and tasty music. You can make it plenty dirty with cupping a vocal mic into a PA.
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