Cisco
1 post
Jun 30, 2009
11:02 AM
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I have these amps and I want to start using them for playing blues harp. I know that in their stock configuration that the 12AX7 pre-amp tubes are too much gain and cause a lot of the feedback issues. I would like to hear what have harp players discovered are good pre-amp tube combinations (tube type and position) to make these amps harp friendly.
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Kingley
149 posts
Jun 30, 2009
11:16 AM
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On both of those amps as you look at them from the back.
Change the tube / valve on the far right (V1) to a 12AY7. That'll cut down the gain and allow you to drive the amp more for harp.
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LIP RIPPER
71 posts
Jun 30, 2009
11:22 AM
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Let's see if I can get this right.
12ax7 = 100 gain
12at7 = 70 "
12au7 = 17 "
I am using JJ tubes. They're about 10 bucks a piece. I'm using the 12au7 in my Epi Valve Jr and it allows me to crank it up quite a bit more before the feedback starts. I think their number is a ECC82 for the 12au7 and ECC81 for the 12at7. But this all from my middle aged memory so double check.
LR
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Kingley
151 posts
Jun 30, 2009
11:36 AM
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Lip Rippers gain values are right I think.
A 12AY7 is between the 12AU7 and the 12AT7 in gain factor.
A 12AU7 will really allow you to crank the amp, but it'll also cut back a lot on the liveliness of the overall tone. That's why the most desirable preamp tubes for harp are 12AY7 and 12AT7
There are numerous set ups for the Bassman which allow for different tonal nuances, but the classic (and original) set up is (left to right) 12AX7, 12AX7, 12AY7.
Different brands do also have tonal differences. NOS RCA sound different to JJ's for example.
Also the Power tubes have an effect, for example JJ Tesla 6L6GC tubes sounds different to the Tung Sol 5881 tubes.
Different rectifier tubes will also increase or decrease the sag factor in the amp. A GZ34 for example will give you a harder edge than a 5UG4.
But be careful. If you start swapping over power tubes (6L6) and rectifier tubes you really need the amp rebiased every time or you could risk doing some damage to it.
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Tuckster
204 posts
Jun 30, 2009
11:39 AM
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I think you're correct,if my OLD memory serves me right. AY's are about 40,I believe. I use AU's in my Bassman head,cause that's what I had lying around. They really knock the gain down. AY's might be a better compromise.
Sorry-posted that before I saw Kingley's comments.
Last Edited by on Jun 30, 2009 11:44 AM
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LIP RIPPER
72 posts
Jun 30, 2009
11:57 AM
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That settles it,I gotta order me a "y" to try.
This damn hobby is costin me a small fortune!
I just had to throw that in,
:>}
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Cisco
2 posts
Jun 30, 2009
1:38 PM
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I already have a couple 12AY7s and 12AU7s ordered but I wanted to get everyone's experience on this for harp amp changes.
On the side I mod Fender Hot Rod Deluxe & DeVille amps to make them more user friendly and understand how to properly tube them according to what the guitar customer wants. But this is my first plunge into the world of harp tweaked amps. Here are the gains for different tube types:
12AX7 - 100%
5751 - 70%
12AT7 - 60%
12AY7 - 44%
12AU7 - 20%
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ianharpo
2 posts
Aug 15, 2010
7:26 AM
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Resurrecting an old thread I know but I cant find the answer anywhere with the search facility. I got a blues deluxe re-issue and play guitar and harp through it. Whats the best tube swap for controlling the feedback on the green bulet that I use. I play a clean guitar so I guess I can sacrifice gain
many thanks guys
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Greg Heumann
710 posts
Aug 15, 2010
8:42 AM
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For most people, a single swap isn't enough. I replace V2 and V3 with 12AU7's and leave the 12AX in V1, subbing a 5751 or 12AT there if necessary.
Everyone I've ever done this for was very happy with the results.
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/Greg
Last Edited by on Aug 15, 2010 8:51 AM
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DeakHarp
153 posts
Aug 15, 2010
8:48 AM
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Here is what i run in my 59 RI
from left to righ
5U4 RCA . 5881 Tunsol 12AX7 GE 12Au7 GE 12Au7 GE .. All tubes are NOS .. Except for the 5881 ... i can get the gain in both channels up to 6 with a pacth cord to jump the channels ..Treb on 3 Bass on 12 Mid on 3.5 Presence 3.5 ... I varry the Mid/Pres a little higher if i need to cut more ... also the Treble i might jack up to 4 sometimes ...if i want to Cut real good ....the pacth wire jumping the channels are in channel 1 high imput .. criss crossed to channel 2 in the Bright .. I plug my Mic in channel 1 Normal ...
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Have Harp Will Travel
www.deakharp.com
Last Edited by on Aug 15, 2010 8:57 AM
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Tuckster
720 posts
Aug 15, 2010
8:51 AM
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Deak-Does that mean you're keeping it a secret? :)
If you retube for harp is it still OK for guitar?
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DeakHarp
154 posts
Aug 15, 2010
9:06 AM
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No tuck ... it dont sound good for guitar if you are cutting with a band for guitar it needs X7's across the board ....No secret ... I like to share my info i gatherd through my 37 yrs of playing ....Its not healthy to bottle up all yur info ...You wind up a bitter old man ..LOL
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Have Harp Will Travel
www.deakharp.com
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ianharpo
4 posts
Aug 15, 2010
9:20 AM
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Deak, sorry man but still a little confused (probably my fault for not being clear) I want to use the amp for both Harp (with a green bullet) AND guitar using both inputs. The inputs on a blues deluxe are hi z and lo z but as I understand it act the same when both used. Anywayhooo, I want to change out some tubes to stop the pesky feedback whilst still having it useable for the guitar.
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DeakHarp
156 posts
Aug 15, 2010
9:40 AM
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Good luck with that Ian ....Its like a woman some got all the bells and whistles ... and others have one or the other ...... You can always invent a amp that does both ... with two Amps in it .... It would be great for street buskers ....Hell throw in a PA Channel too ......Those old Basemans had 4 imputs in them for a reason ...the old dogs sang and played through them while on Maxwell St .....
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Have Harp Will Travel
www.deakharp.com
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hvyj
531 posts
Aug 15, 2010
9:59 AM
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Eurotubes sells a set of 3 preamp tubes (JJs) as a kit to re-tube the BJ for harp. Very effective tube swaps. You have to call or email them to ask about it as the kit is not listed as a separate item on their website.
The kit consists of an ECC81 (12AT7), an ECC 83S (12AX7) and an ECC832 (12DW7). They are to be installed in the BJ in that order from V1 to V3. The 12DW7 is a tube with an unbalanced triode that goes in the phase inverter slot and is supposed to fatten tone for harp if used that way in certain amps. Opinions on the effectiveness of using an unbalanced PI tube vary, but I think it sounds pretty good in the BJ and in my Super Reverb. Doesn't work in all amps, though--for example it doesn't do anything in a Princeton Reverb.
Last Edited by on Aug 15, 2010 10:07 AM
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LittleJoeSamson
404 posts
Aug 15, 2010
12:09 PM
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For the Blues Deluxe RI and the '59 Bassman RI, I would try subbing the pre-amp tubes thus: V1-5751, V2- 12AY7 or a used 7025/AX7, V3- 7247/12DW7 or 6829 . ( IMO the 6829 works better as PI than a 12AT7 ).
Same thing for the Blues Jr. except leave the 12AX7 in V2. It uses only 1/2 to run the reverb.
The 7247 as phase inverter has worked great for me. Sure would be interesting if an unbalanced dual triode were made that was 1/2 12AX7 and 1/2 12AY7 !
( 7025, NOT 7205! Dyslexic in the morning ! )
Last Edited by on Aug 15, 2010 1:05 PM
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Greg Heumann
711 posts
Aug 15, 2010
12:17 PM
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@ianharpo: Are you playing harp in a rack WHILE playing guitar? If so, forget everything that's been said. Different animal.
If however you want good fat cupped tone, then unless you have independent control of the gain on both input channels, you'll either have a good harp amp that's feedback-friendly and fat, with a dead guitar sound, or a good guitar amp that will suck for harp.
Deak is the MAN - and you'll notice his more complete tube recommendation jives with what I said - the FIRST STEP is (from left to right) 12AU 12AU 12AX.
These tubes (unlike some of the others mentioned) are very easy to find and reasonably priced.
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/Greg
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barbequebob
1130 posts
Aug 15, 2010
12:55 PM
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I own a REAL '59 Bassman, and this is the tube layouut I use from 1st preamp tube to rectifier tube and these numbers are the stock numbers they all came with:
12AY7 -- (I use NOS GE or RCA 12AY7/6072A)
12AX7 -- (I use a 1962 NOS GE 12AX7, and most 12AX7's today are really 12AX7A/7025's, which are more trebly by comparison)
12AX7 -- (I use NOS GE or Phillips/Sylvania 12AX7A/7025)
5881 -- (I use NOS Phillips/Sylvania, which is real close to the orginal equipment Tung Sols and I haven't used the reissues yet)
5881 -- (Ditto from above)
5AR4/GZ34 -- (I use an NOS Mullard)
I've owned this amp since I bought back in 1983, when I got with a silver faced Fender outboard tube reverb thrown in the deal for a grand total of $425.00.
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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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DeakHarp
158 posts
Aug 15, 2010
1:12 PM
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Greg i forgot to mention im looking at the back of the amp from the back .. left to right .. 5u4 . 5881 tun sol RI .. 21ax7 .. or 5751 .. 21AU7 21AU7.
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Have Harp Will Travel
www.deakharp.com
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ianharpo
5 posts
Aug 15, 2010
1:24 PM
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Not not in a rack.......jeez thats just too clever. It's just on some numbers I play harp and on others guitar.
I dont play guitar through the gain channel though ....like I say I play that clean with some reverb
So to sum up...........I cant swap some tubes and get that dual purpose amp?
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strawwoodclaw
93 posts
Aug 15, 2010
2:20 PM
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I think 5751 tubes are the best you wont be able to turn the volume right up but it wont be as bad as a 12ax7. 12au7 will probably sound too tame & will take away your amps mojo you don't want that happening. try changing all the ax7 to 5751 & maybe 12at7
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walterharp
424 posts
Aug 15, 2010
4:27 PM
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in the bassman, the 12dw7 might work in first position for both guitar and harp it as a 12ax7 on 1 side and a 12au7 on the other. this is why some people like it for harp in the 3rd position because it causes the two power tubes to get a bit out of sync and offers some more distortion.
If you use the 12dw7 in the first tube position, you could not bridge the channels 1 and 2 channels and plug into the high gain side with guitar the the lower gain side with harp, because the first preamp tube is split between the 1 and 2 inputs. One potential thing that might interfere with this is if the side with the 12au is on the "bright" channel, this channel does not sound as good with harp, and you might have to clip out the bridging cap to make it work.
in all, i am with bob, and the lower gain tubes tend to take the spank out of the bassman type amps for harp (and really for guitar). the volume control is more sensitive and you turn it up less to get the same volume and get less sweep out of it with the higher gain tubes, but once you get it dialed in it sounds better to me with the higher gain tubes. A volume control on the mic can help here too.
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5F6H
274 posts
Aug 16, 2010
12:53 AM
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Blues Deluxe & Bassman have significantly differing circuits, by al means try lower mu tubes in V1 & V2 (there's no right wring & whatever works...well, works) but I only usually change V3 next to the power tubes with 5751/12AT7/12AY7 (12DW7 is an option too) on a Blues Deluxe/De Ville.
The RI Bassman can be a kick ass amp with even the stock preamp tube set up (AY/AX/AX from R to L), 90% of the players I know use this set up. Sometimes a 5751/12AT7 in V2 can soften & sweeten things nicely too, for very high output mics a 12AU7 in V1 can work too. For a very overdriven sound a 12DW7 in V3 might do the trick.
Remember also that gain is a factor in the power section too, try differing rectifiers like 5U4G and if you have a LTD with bias pot (or a bias rite & some spare tubes) try and find some tubes that idle around 15mA each - anything from 7mA per side upards will work, lower currents will be very dry & crunchy, higher currents will be smoother & get brighter once you are much past 20mA. The stock 5881WXT are plenty adequate & compare favourably to most current production tubes.
Last Edited by on Aug 16, 2010 5:15 AM
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Joe_L
540 posts
Aug 16, 2010
9:13 AM
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Bob - has your REAL 59 Bassman been modified for harp?
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5F6H
275 posts
Aug 16, 2010
9:50 AM
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Joe, don't mean to butt in...(but doing it anyway...why do people do that, like when they say, "I'm not being rude but...") Bob has written many times (here & elsewhere) that his bassman is how it left the factory, e.g. no harp specific mods...I'm sure he'll correct me if I'm wrong...(I'm pretty sure I'm not)...:-)
A "good" bassman is a pretty useable tool for harp, just as it comes...that's not to say a few tube subs/circuit tweaks can't make it a better match to a particular player (it's their amp and their buck afterall). And to me, that's really the nub of the matter...if, with your chosen mic, you're perfectly happy with your bassman then great...but I also don't hold to the "real men don't need mods" attitude either, basically because the 5F6A has only 1 published circuit, but in practice has a dozen different permutations of components from beginning of the run to '60. Subsequently, 2 REAL bassmans (or reproductions) can sound very different, especially when typical tolerances are taken into account. So in many cases it's as much about matching the amp to the player as to the harp, per se.
The only real "harp specific mod" that can be made to a bassman is the very hi Z input resistor load...some don't feel this is necessary with all mics...anything beyond that is up to taste & tuning the amp for a particular setting (say going for max vol over "classic" tone, or a specifically desirable response/feel). Most old ones could do with a rebias, just because wall AC voltages have gone up with time (contemporary builders fit bias pots to allow for this).
I typically prefer a drop in preamp voltage, just enough to curb a degree of feedback, & warm the amp a little with harder rectifiers... a soft rectifier & a tube sub may do the job also... just my GB£0.02.
Last Edited by on Aug 16, 2010 9:50 AM
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barbequebob
1136 posts
Aug 16, 2010
10:16 AM
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Joe_L, it has never been modified in any way shape or form since I've owned it. When I bought it, it didn't have the tweed and from doing a little research, I found that it was a factory recovering job, and in the mid 60's, when you brought it back to the factory to get that done, they didn't retweed it, and used the same grill cloth and script the Super Reverbs used and covered the amp with vinyl tolex.
The only thing I had to do in the late 80's was replace the speakers and no one at the time were doing alnico magnet speakers remotely close to the original Jensen P10R's that were stock (the new ones are NOT the same), and so I had 25 watt Celestions in there that they now don't make anymore as the closest thing to it.
Filter caps at the same time were replaced with original equipment Astrons and so, essentially things are unchanged.
I've never done any mods and found most of those not realy worth a damn in my experience and I subscribe to the GIGO theory, AKA garbage in, garbage out, meaning if the tone is crap going in, the tone is gonna be crap coming out of it.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
Last Edited by on Aug 16, 2010 10:17 AM
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Joe_L
542 posts
Aug 16, 2010
11:34 AM
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Mark - I was just messing with Bob a bit, but I do enjoy the story. I didn't know about the Tolex though. It's an interesting story.
I agree. Garbage in, garbage out.
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swampboy
11 posts
Aug 18, 2010
8:43 AM
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I'm not sure about the Bassman, but on my Vibroverb, V1 is the preamp tube for the normal channel only and V2 is for the Bright channel only.
I sub V1 for a 12AY7 and play harp through the normal channel. V2 is a 12AX7, and the guitar goes through the Bright channel totally unaffected.
Try it.
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barbequebob
1143 posts
Aug 18, 2010
8:54 AM
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One thing I should mention about all Bassman RI's is that all of their preamp tubes since day one has been 12AX7's and have never had 12AY7's in them as original equipment. All original real '59 Bassmans all came with 12AY7's in the first preamp tube slot.
When setting tone controls for Vibroverbs and 4-10 tan Concert Amps, it is a TOTALLY DIFFERENT circuitry than 90% of all other Fender tube amps because wheras amps like Bassmans, Twins, Super Reverbs uses what's called passive tone controls, meaning that when you turn the tone controls all the way up, you are actually setting it at flat, being the already preshaped sound out of the factory and then the only thing the tone controls actually do is cut and they don't boost ANYTHING at all.
Vibroverbs, 4-10 Concerts and some 2-10 Supers use what you see on all solid state amps and late 60's Marshall, HiWatt, Orange amps use and that's active tone controls, meaning that either side of half way, you are boosting for real and so when setting the tone controls on the Vibroverb/Concert/Super, start everything at half way and most likely you'll either leave that their or turn them down, not up.
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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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swampboy
12 posts
Aug 18, 2010
9:06 AM
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That's right about the tone circuit,Bob.
Do you know if V1 and V2 on the Bassman are for the seperate channels? I mean if you take out V1 completely will the Bright channel still work? If so you can sub a lower gain preamp in V1 and have harp and guitar in different channels each with their own peamp tube like I do with the Vibroverb.
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5F6H
277 posts
Aug 18, 2010
9:45 AM
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@ BBQ Bob:"When setting tone controls for Vibroverbs and 4-10 tan Concert Amps, it is a TOTALLY DIFFERENT circuitry than 90% of all other Fender tube amps"
I have to disagree somewhat here. All Fender tube amps use passive tone controls (they all just cut)...some of the tolex Fenders, such as the 6G14 Showman (NOT ALL, certainly does not applly to all amps of a certain model/year) use a tone stack closer to the James (sometimes wrongly called Baxendall, they are different things) tone stack.
The real big difference between say a tweed 5E#A/5F Bassman/Bandmaster/Super/Twin/Pro and the tolex amps, is that the tweeds had the volume after the input triode, but before the tube that drives the tone stack. The tolexes (inc. Vibroverb/Concert etc) have the tone stack right after the input triode, running directly into the volume control, with no tube stage separating them.
The Vibroverb & some Concerts/brown Bandmasters/Pro/Twin/Super etc had what's called a tapped treble pot...this is a minor alteration to the well known BF/SF tone stack & can be fitted/removed as you please (or even hardwired with a cap & resistor on the treble pot).
The treble, mid, bas controls otherwise are in the same circuit in either a tweed bassman, or a tolex amp, be it brown/BF/SF. The difference really being that the tolex circuit has a much greater "sweep" & even uses smaller value bass pots because of this (though they effectively do more with 250K that the bassman does with 1Meg). This is because the tweed bassman volume is isolated from the tone stack & the tone stack has to deal with more gain.
I do agree that the tolex tone knobs, especially the bass, can be massively overused (which is Bob's principle observation), for a SR/Concert I usually end up with this between 5&6, treble around the 4 mark. Tolex amps have smaller mid pots (where fitted) than tweed amps, so a SR with the mid at 10 still has less than half the mid of a tweed bassman at 12 (though the cathode follower tone stack in the bassman makes for a middier tone at most settings, which is partly why Fender eventually dropped it for the cleaner, mid scooped tolex style).
Another little known trick is to use the tone controls of the channel you aren't using with a tolex amp, there is still some bleed through, though not as much as with a tweed amp. With vol & bass all the way up, the other channels treble control can subtly effect cut, like a 2nd presence. you would only use this if you already have the presence full up & need more cut. May not work on old Concert/Bandmasters with centre volume, due to larger channel mixing resistor on the mic channel?
Swampboy - Only V1 in a tweed bassman is split between the channels. You could try, as has been suggested, a 12DW7 in V1, Normal channel is now lower gain & might be more useful for harp (no guarantees), Bright channel is regular 12AX7 gain, if too bright just snip the 100pf bright cap & you effectively have 2 normal channels.
These are the facts...the circuit/wiring bits, not where/how to use the pots...just turn them to where they sound best, like any amp :-).
Last Edited by on Aug 19, 2010 2:12 AM
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walterharp
427 posts
Aug 18, 2010
12:20 PM
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yes, just v1... that is what i suggested. what i was not sure about is which side the lower gain of the 12dw7 would be on, and it is good that it is on the regular channel, because that channel sounds better with harp than the unmodified bright channel. The bright channel with the higher gain would be more likely to provide an acceptable sound for guitar without snipping the cap. Thanks for clearing that bit up mark.
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barbequebob
1147 posts
Aug 18, 2010
12:46 PM
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The presence control on tweed Bassmans is basically a secondary treble control and when I use a crystal or ceramic JT30, I usually turn the treble completely off and set the presence at 8.
Anothor not well known thing on Tweed Bassmans is the fact that the two volume controls interact with each other. Once I get what I want set with the tone controls for the channel that I'm plugged into, and in this case, I use the normal channel, as soon as the volume control for the normal channel is set how I want it, I then turn the volume control for the bright channel on 6.
Now what does this do?? When you turn up the volume control for the channel you're NOT plugged into, and turn it up to 6, it puts the amp into maximum gain, and also boosts the bass and the lower midrange for real. However, if you put that past 6, you will lose volume and the higher you set it past 6, the more substantial the loss becomes.
I've found that this works much better than bridging channels on this amp, which to my ears, thins things out too much and the notes lose definition.
This also works the same on the Bassman reissues, but the only other amps I've seen this work on are the tweed Twins from the same era, the Custom Shop Vibrolux, and the Custom Shop Vibro Kings and no other Fender amps does this.
The best information available on the differences between the real '59 Bassman and the reissues is in a chapter of the book, "A Desktop Reference of Hip Vintage Guitar Amps," written by Gerald Weber, the owner of Kendrick Amps (which put out the very first harmonica only amp, the Texas Crude Classic in 1992) and is available thru his site http://www.kendrick-amplifiers.com or thru http://www.amazon.com.
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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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5F6H
279 posts
Aug 19, 2010
1:26 AM
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@ BBQ Bob: "This also works the same on the Bassman reissues, but the only other amps I've seen this work on are the tweed Twins from the same era, the Custom Shop Vibrolux, and the Custom Shop Vibro Kings and no other Fender amps does this."
The Custom Vibrolux Reverb has exactly the same tone stack as the 6G#A Fenders (with treble & bass controls) & the brown vibroverb, they work the same, but with the tolex amps you need to turn up all the controls, not just the volume, the treble is critical too.
The differences between the RI & real bassmans is construction method (PCB over eyelet board, transformer quality), ...basically the things that let Fender build & sell the amp for under half what a handwired repro costs. The 59 RI has the same circuit as the later bassman amps (just has filter caps wired for higher voltage, which amps like the Kendrick 2410 also do), runs similar voltages under current load (most of the time, you do get a few weirdos)...when biased up with good tubes & speakers the best sounding amp will be the best sounding amp, maybe an original/repro, may be a RI. It doesn't matter who made this resistor, or cap if it is not the most desirable value. I appreciate it sounds like I am bucking conventional wisdom, but this is something I have seen, many, many times...(I have seen/played/worked on all the commercially available bassmans).
Gerald Weber is right in his bassman article, but remember that he is writing from the guitarists perspective, he tends to promote his harp amp (different animal altogether) over his 2410 with harp players.
The thing is that nobody commercially makes a hand wired repro of the 59 RI, the Clarke is the closest thing. Victoria will make some "in keeping" adjustments on request.
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Harpman Moe
1 post
Feb 14, 2011
9:14 AM
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Do NOT use a 12DW7 in the phase inverter (V3) on a Blues Jr. It has no effect on feedback or tone and will lower the output. Billm does not approve of a 12DW7 in the V3 position either but instead recommends it in the V2 position ONLY if you have done the "cathode follower mod" as it take some of the load off of the tone stack. If you have not done the mod it will have no effect as that section of the V2 tube in the original configuration is actually not used.
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5F6H
536 posts
Feb 14, 2011
9:56 AM
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@ Harpman Moe - The Blues Jr (like the Pro Jr/Blues Deluxe/5F6A Bassman/Super Reverb/Twin Reverb/Blues Deville) uses a "long tailed pair" phase inverter in V3. Fitting a 12DW7 here unbalances the phase inverter...this has a distinct effect on tone, it effectively drops gain, it may/may not affect power output....but it can't have "no effect on feedback or tone". I don't think it's always, or even particularly often, a silver bullet...but I wouldn't rule it out. In some amps it sounds better than others & is easily subbed if you don't like it.
The practice of unbalancing phase inverters to reduce feedback & change the tone is well documented in harp amps, even Peavey have a method for doing this in some of their new guitar amps.
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daharpo
1 post
Nov 30, 2014
11:26 PM
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Hello, I own a Fender Bassman Re in its original configuration. I just changed the preamp tubes with this configuration V1 = V2 = AX7 au7 V3 = AU7. With this configuration I have no feedback, but when I played with harmonicas low than G harp, like LA or G i lose a lot of brightness and clarity. I play with a ElectroVoice RE 10 mic and LW HarpDelay pedal. An idea for this loss of brightness ? Thank you.
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Wendell
38 posts
Dec 01, 2014
5:36 AM
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My bassman tubes, all nos hamfest finds:
v1 6072 (ay)
v2 5751 (70%)
v3 6189w (au)
6L6WGB
5U4GB
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daharpo
2 posts
Dec 01, 2014
6:35 AM
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Oups error ...
Thanks for the answer.
My config is v1-->12AX7 V2-->12AU7 and V3--> 12AU7 ... SORRY
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Greg Heumann
2886 posts
Dec 01, 2014
8:41 AM
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No matter WHAT you do, if you can still get feedback with the volume controls all the way up, YOU HAVE NOT REDUCED OUTPUT below the maximum usable level. in practice, lowering gain with the recipes above does not equal lowering output. It simply adds travel to the gas pedal. (And it can have subtle impact on tone.)
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
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Barley Nectar
576 posts
Dec 01, 2014
11:24 AM
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I have a '95 Bassman. I run 12AY7, 12AX7, 12AX7, 2x6L6WXT with a 5U4 rectifier. Mic is a Shure 99A86 element in a Turner shell. Amp is not modded.
Set your amp how you like then set the unused volume control to "6". This will fatten the tone. I do not jump channels. I feel that the 5U4 rectifier helps prevent feedback by reducing the voltages throughout the circuit. My highs are high, my lows are luscious and it will feedback if I want it to...BN
Last Edited by Barley Nectar on Dec 01, 2014 11:29 AM
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arnenym
326 posts
Dec 02, 2014
12:50 AM
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Just a little warning!
I repaired 2 Bassman with overheated resistors caused by AU tubes in V3. One RI and one LTD. I heard about other amps from other amp tech's.
I measured temp on the new resistors i replaced and they got a temp over 80 degrees C / 180 degrees F with a 12AU7 in the socket!!
With a 12AX7 it be 40 degrees C /105 degrees F.
I measure without back panel. When you put on the backpanel the temperature rise very much.
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daharpo
3 posts
Dec 02, 2014
11:24 PM
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Thank you for your answers. What we I try your configurations and I'll let you know. I called a technician confirms me the danger of au7 lamps for bassman amplifier for heating.
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barbequebob
2776 posts
Dec 03, 2014
10:35 AM
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One thing about using 12AU7 tubes to make amps distort more and be so called "harp friendly," is that tho the amp to your ears may sound good to you when you stand about 3-5 feet from the amp, once you go beyond 10-20 feet, everything sounds like total mush and the amp loses definition quite badly.
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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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hvyj
2600 posts
Dec 03, 2014
11:10 AM
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I was hesitant to say this until I saw BBQBob's post, but my personal experience with AU7 tubes is that they just don't drive hard enough to get good tone out of any of my amps. But i don't use bullet mics or harp specific amps. FWIW
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barbequebob
2778 posts
Dec 03, 2014
11:54 AM
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@hvyj -- I see that very same problem regardless of what mic is being used, plus you lose TONS of dynamic range on top of that and if you've worked hard on breath control in order to achieve better tone control as well as tonal color variety, it puts a HUGE hurting on that as well.
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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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hvyj
2601 posts
Dec 03, 2014
12:02 PM
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@BBQBob: Yes. What you are saying is entirely consistent with my personal experience.
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Kingley
3764 posts
Dec 03, 2014
12:20 PM
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I'm generally speaking not a fan of 12AU7 valves in amps for harmonica. I find they tend to kill the amps tonal qualities far too much. In the case of amps like the Bassman and the Pro Jr they kill the amps liveliness and make the amps sound too mushy and muffled to my ear.
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arnenym
327 posts
Dec 03, 2014
1:55 PM
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1+ on Kingley and hvyi
Last Edited by arnenym on Dec 03, 2014 1:56 PM
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MJ
744 posts
Dec 03, 2014
2:55 PM
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I have a 5f6a which I built to the specs of the original. I use 12ay7' 5751 and 12ax7 V1 to V3. I lie the way it sounds for my style of playing.
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