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Dirty-South Blues Harp forum: wail on! >
modified HR Deville
modified HR Deville
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SuperBee
273 posts
May 26, 2012
2:53 AM
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I just got my HR Deville back from the workshop. this is a barely-used, 15 year old 4x10 model. Thanks 5F6H and Val King for the mod suggestions.
this is what was changed:
R3 from 1meg to 4.7meg
R4 and R11 to 120k.
R9 to 820K
C1 to 220uf.
R75 to 50K
upgraded power rating of V3 plate resistors.
Rebias power tubes 15mA per tube.
rewired speakers to 2 ohm parallel.
schematic:
LINK
I just did a little testing this afternoon, and i am quite happy with it.
it is perhaps not as loud as i hoped it may be, but it is quite loud and i think it should cut through.
what i have found is that if i push the volume to feedback threshold it is probably too dirty. that is almost at 4. if i drop it back to about 3 and 1/2 where there is no threat of feedback it sounds really good. its dirty enough if i push for it but not so dirty that the notes are lost, and chords and difference tones are room-filling.
i'll have to play around with it some more...band practice tomorrow so that will be a good test...
i think its at least as good tonally as my Silverface Princeton Reverb, and much louder. and heavier. i am gonna have to keep my back strong.
Thanks again Mark, for your suggestions.
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Last Edited by on May 26, 2012 2:56 AM
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S-harp
37 posts
May 26, 2012
4:58 AM
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Very interesting ...
I also have a HR Deville about 15 years old ... and been looking for some mods ... It gets the job done just fine as it is, especially the warm acoutstic tone with dynamic mics, but I'm courius what it can deliver after some mods.
Here are some questions from somebody who don't understand much about amps insides and specs.
The speakers ... stock or replaced?
The channels ... mod on ch 1 of course .. 2 and 2HR?
The tone .... Difficult question, but when and how does the tone break?
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The tone, the tone ... and the tone.
Last Edited by on May 26, 2012 5:01 AM
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SuperBee
277 posts
May 26, 2012
7:01 AM
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speakers are the stock Eminence "fender special design"
i dont plan on using the higher gain channels. i guess the mods would affect them all, though the R9 change i'd have to think about. to some extent these mods are to calm the preamp; i cant see much point in using the high gain channels. if i want to play at lower volumes i'll use a smaller amp.
the idea as i understand it is that this amp has loads of clean headroom which in stock form you just arent gonna use before feedback strikes...one approach is to retube the preamp. i've heard n HR deville which has just had the R3 and R4/R11 changes as above, and retubed with a 12AU7 in V1 and 12AT7 in V3 and it was great. I decided to stay with the 12AX7s and try these other changes to calm things down. i may yet try a 5751 in V1 and a 12AT7 in V3. the upgrade of the V3 plate resistors was primarily to deal with this possibility as the retube places a bit more strain on them, and they sometimes fail in normal use.
i'm really not the guy to answer this, but i think 1 thing ive done is lower the point at which the amp starts to break up (if you like). the bigger C1 should perhaps give it some more bass, but changing the OT tap and speaker wiring should lighten it up. i am playing high impedance mics into it...my crystal is relatively weak, and my CMs are hot...the crystal feeds back before it gets as loud as the others, but it has a quite nice clean tone...not what i'd want all the time, and my main driver for this amp was LOUD, so i can hear it with a loud band. at 3.5 it breaks up nice, to my mind. at (just touching the tail of the) 4 it is right on the cusp of feedback and distorted as all get-out. i dont really like it that distorted, though i think many do. these amps have annoying volume pots too i think, which have a very steep taper between 3 and 4. its a bit late tonight to try recording samples
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Last Edited by on May 26, 2012 7:02 AM
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5F6H
1213 posts
May 26, 2012
7:52 AM
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Hi Super Bee,
Glad to see the changes are going in the right direction. A 12AT7 in V3 will give you more clarity & bite at the expense of a little bass (may not be an issue as it is a very bassy circuit to start with).
There are more tweaks, fairly minor & easy to do, but I'd live with it for while & try & determine what might be the next course of action.
You have a little scope to go cooler on the bias, but the tone will get progressively fuzzier.
R56 (PI tail) could go larger, say to 10K-20K this will lower gain in the PI, go too far & the amp will be too "loose".
With the 2ohm speaker load, R69 value could be halved by tacking another 47K in parallel (56K or 68K would also work for the additional resistor). Again this will slightly drop gain.
I think the changes you have made already are likely to give the bulk of any improvement.
All the best, Mark.
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SuperBee
279 posts
May 27, 2012
3:56 AM
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Tried it in the band room today. How nice to feel like I could always get enough volume. Sometimes it was a little drowned out but more often I was toning it down a little so as not to drown out others. Used my VC more than ever before! Takes my pedals very well, lonewolf delay and octave. Sweet and round with delay, paper tearing with octave. It'll do me for a while I think. Now, what to do with my old Ashton Viper 30?
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