Rhartt1234
233 posts
Apr 23, 2017
2:35 PM
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The 12ay7 in my Pro Junior died. For years I've been reading BBQ Bob's various posts about GE 5-Star Black Plates and I just can't quit force myself to pull the trigger on a $50 tube.
In my research for an alternative I came acrosss some info in the ECC832 which is half high gain half low gain? I don't know how all that sh!t works but it seems interesting.
Any other thoughts or advice? Like "Ryan, just get a JJ 12ay7. All that other crap isn't worth the time or money."
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hvyj
3271 posts
Apr 23, 2017
3:39 PM
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An ECC 832 is one half 12AX7 and one half AU7. So, in an amp that uses both sides/triodes of the phase inverter tube, an ECC 832 will UNbalance the phase inverter. For harp, this is supposed to thicken the tone, but there is some debate about that. It also will reduce gain somewhat which DOES help control feedback. Personally, I use an ECC 832 in the phase inverter slot of my Super Reverb and I like it.
This is contrary to conventional wisdom, but when substituting lower gain tubes to control feedback, I usually like to tube down the BACK end of the preamp tube chain rather than the front end because I think I get better tone that way. But I don't use a bullet mic if that makes any difference. Anyway, using the ECC 832 is consistent with that approach (tubing down the back end rather than the front end). It works for me.
I also use an ECC 832 in the middle slot of my Peavey Delta Blues, because it steps down the gain on the drive channel which makes the otherwise feedback prone drive channel usable for harp by controlling feedback. I don't actually use the drive channel all that much, but with the ECC 832 I can if I want to.
FWIW, JJ also makes an ECC 823 which has the triodes in reverse order. My Princeton Reverb's Phase Inverter uses only ONE triode of the tube and the position of the AU7 in the ECC 823 allows you to have the equivalent of a AU7 for the PI which I think helps control feedback.
I think you may like like the ECC 832 in the PI slot of your Pro Jr.
Last Edited by hvyj on Apr 23, 2017 3:54 PM
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SuperBee
4636 posts
Apr 23, 2017
3:51 PM
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Ecc832 aka 12dw7
One triode is like a 12ax7, the other like a 12au7
Besides the gain factor, I'm not sure of the other important electronic characteristics of the tube, that is, whether it is the same as the the ax/au in those regards also.
I dunno the pro jr very well. I mean I've done some work on one but I don't know how well they handle tube subs. I'm always wary of using 12AU7 (and 12AT7) in positions which were designed for 12ax7 as the current draw is significantly higher and can stress the plate resistors.
My hotrod Deville for instance would not be a good candidate for 12au7 without also uprating the plate resistors to handle more current. Pro jr is from similar design school but I don't know for sure. Just something to check into maybe.
Or you could just get a jj12ay7 and not bother with all that other crap.
The $50 tube will probably last a few years too.
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hvyj
3272 posts
Apr 23, 2017
4:02 PM
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As I understand it (and I may be wrong) the 12AT7/ECC81 and the 12AU7/ECC82 have the CAPACITY to handle higher current but do not necessarily draw higher current all the time just by being there. I've had two ECC81/12AT7 tubes in my DB for the last few years with no ill effects.
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1847
4081 posts
Apr 24, 2017
7:32 AM
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12ay7
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barbequebob
3407 posts
Apr 24, 2017
10:17 AM
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As far as the NOS stuff, my favorite is the GE 5 star, but for less money in the NOS market, the next best thing would be anything from RCA, especially if it's made prior to the mid 60's. I'm not a fan of the new production from EH but I have heard good things about the JJ's, but since I haven't tried one myself, I can't comment on that.
On my Pro Junior, which is one of the last ones to have the same blue alnico magnet speaker used on the original Bassman RI's made by Eminence, I've been using the NOS versions of the stock tube numbers, but they're all made by GE. An alternative to that is to use the Tung Sol reissues of those (all Fender tweed amps and most of the vintage Gibson amps all use those right out of the factory back in the day.)
If you can score a super rarity, a NOS Tung Sol 12AY7, get it.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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shakeylee
631 posts
Apr 24, 2017
1:03 PM
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oh darn Ryan,i was just in CT and i have tons of them.
my favorites are rca 12ay7 and mullards,but i have ecc832's and 12wd7's etc.
if i go back on mother's day,i'll let you know.
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www.shakeylee.com
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Joe_L
2692 posts
Apr 25, 2017
11:24 AM
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I ran an Electro Harmonix 12AY7 in my Pro Junior. It sounded fine. I experimented with 12DW7. If it thickened the tone, I couldn't hear it. Same thing in my reissue Bassman.
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The Blues Photo Gallery
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shakeylee
634 posts
Apr 25, 2017
7:26 PM
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But it performed satisfactorily,albeit with no noticeable tone change?
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www.shakeylee.com
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Joe_L
2694 posts
Apr 26, 2017
4:23 PM
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Yeah. It amplified the sound just fine. It wasn't tremendously different in the feedback resistance department.
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The Blues Photo Gallery
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chromaticblues
1771 posts
Apr 28, 2017
11:02 AM
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Ryan that is the tube I use in my Kalamazoo. It works and sounds great. If you use it in the first section it should work fine. Just don't put it in the socket next to the power tubes.
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hvyj
3274 posts
Apr 28, 2017
12:28 PM
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I don't know anything about a Kalamazoo, but in most other amps, I think putting a 12DW7/ECC832 in v1 will step down gain so substantially it will erode tone. The preamp tube next to the power tubes is the phase inverter in most amps which is where I put this tube (it works well there for me) and where others have recommended it to be used. A Kalmazoo may be different. I don't know. IMHO, an AU7 in v1 will erode tone, but if you like using an AU7 in v1 then a 12DW7/ECC832 should work as well or better for you.
I also use it in the middle slot of my Peavey Delta Blues to dramatically step down gain on the drive channel to make it usable for harp, but, again, I would think that such a substantial step down would not sound good in v1--but maybe a Kalamazoo is different in this regard. OR for those who like using an AU7 in v1 then an ECC832/12DW7 should work as well if not better for you.
Last Edited by hvyj on Apr 29, 2017 12:04 PM
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SuperBee
4651 posts
Apr 28, 2017
2:28 PM
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It would depend on how your tube socket was wired. Some amps the signal goes in on pin 2, others use pin 7.
It usually doesn't make any difference because most twin triode tubes I.e. 12 ax/at/ay/au 7 are gonna give the same result both sides.
If you put a 12dw7 in V1 you will either have stage 1 as an au, or an ax. Typically the signal goes from stage 1 to the volume control and tone stack if applicable, then comes back to stage 2 of the preamp, which is usually the other half of the same tube.
So depending how the socket is wired, if you use a dw you'll have either stage 1 an au and stage 2 an ax, which might be ok, or vice versa which would probably be terrible.
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hvyj
3275 posts
Apr 28, 2017
2:38 PM
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That's why JJ makes an ECC823 which has the triodes in the opposite position/order than in an ECC832/12DW7.
Last Edited by hvyj on Apr 28, 2017 2:44 PM
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chromaticblues
1772 posts
Apr 29, 2017
6:03 AM
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hvyj it depends on what mic your using! Most amps are built for guitar so playing harp you can't turn it up about 3 anyway before it starts feeding back. I don't know what experience you have with amps? I've played through about 100 or more different amps and almost all of them over powered for high impedance harp mics. That is why people put them in the first slot in amps! Most amps Do Not Have The Correct Driver To Put This Tube In As A Driver! BAD IDEA! If you have an amp with a Cathodyne drive which only uses one half the tube then this tube can be used. A 1958 Fender Deluxe 5E3 is the most well known example of this driver set up. The pro Junior may have this I don't know. What I do know is MOST amps do not!
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hvyj
3277 posts
Apr 29, 2017
8:13 AM
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@chromaticblues: that makes sense. Personally, I don't use a bullet mic as I said in my first post in this thread. I do use a volume control, however, and I use it to attenuate the signal going from the mic to the amp to cool it out which controls feedback and (along with tube swaps) gives me a wider usable range on the amp's volume control. For the most part, I play through guitar amps and I don't use harp specific amps unless I'm playing through someone else's rig. I've tried dozens of amps over the years.
For whar I do using the type of set up I play through, I find that I get an unacceptable erosion of tone if I use a 12AU7/ECC82 or a12AY7 in v1/ M. The lowest I find I can go in v1 and still preserve acceptable tone is a 12AT7/ECC81. But I know some players who use a more traditional mic/amp set up who do use lower gain tubes like an AU7 n v1. But that just doesn't work for me. FWIW.
Last Edited by hvyj on Apr 29, 2017 12:07 PM
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1847
4091 posts
Apr 29, 2017
10:38 AM
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check out these tubes i found this morning at the swap meet.
grand total out the door.... $20.00
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hvyj
3278 posts
Apr 29, 2017
12:20 PM
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On the subject of tubes, generally, I've been using JJs and the JJ 12AX7 equivilant called ECC83S. JJ now has another 12AX7 equivalent called ECC83MG. The ECC83MG sounds GREAT! I've replaced all the 83S tubes in all my amps with 83MG tubes and I really like the improved sound. A guitar player I work with did the same thing with his amps and has a similar positive experience.
I know some players denigrate anything but NOS tubes, but as far as current production 12AX7's are concerned, I think the JJ ECC83MG sounds really good.
Last Edited by hvyj on Apr 29, 2017 12:21 PM
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SuperBee
4654 posts
Apr 29, 2017
2:38 PM
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I've never tried a dw7 in the PI, in any amp. I was struggling with wondering how it would be good, ever, but chromaticblues post helped click the grey matter into gear.
So of course if the PI only uses one half of the tube, using a 12 dw 7 is gonna work the same as using either a AX or AU in that position, depending on which way around the socket is wired.
The claims for 'fatter tone through unbalanced signal' that I've seen made as a case for using this tube in the PI can only make sense in relation to amps which use both triodes as part of the PI circuit.
it doesn't appeal to my mind as a desirable arrangement, just on a theoretical basis, but if you haven't tried it, don't knock it I guess.
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