DRRI questions

Discussion in 'Amps and Cabs' started by Jack Dotson, Aug 31, 2008.

  1. Jack Dotson

    Jack Dotson Supporting Member

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    I recently purchased a DRRI and have some questions I hope you guys can help me with:

    1. I want to replace the power tubes so I will have to re-bias the amp. The manual doesn't cover this other than saying to take it to a tech. I have a multi-meter to test with, but I need to know what the test points are, what the correct bias voltage is, and where the bias adjustment pots are located? If anyone knows of a site with step by step procedures that would be great.

    2. I've read that you can jumper between the two channels. Why do people do this and what is the advantage? How is it done?

    3. For you tube rollers, what have you found to work well with the DRRI? I don't want to spend a fortune on NOS tubes, but would like to put in some quality tubes that can be had a reasonable price. I would like to roll in something that would tame the brightness and bit and get warmer a more round sound if possible.

    Your help is appreciated and if you have any other suggestions on how to get the most out of this amp I would love to hear them.

    Thanks.
     
  2. re-animator

    re-animator Senior Member

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    1. can't help ya... i don't mess with that stuff, sorry.

    2. you can.... sort of. The channels come up out of phase with eachother so you can do it, but it won't sound good. a/bing between both channels on the other hand is teh sechsy.

    3. JJs in the power for sure. JJs in the pre are also alright, especially if you want a darker sound, but i find that they lack clarity. The Tung Sol reissues on the other hand are very clear. If i had a DRRI again I would put a tung sol in v-1, then JJs in the rest of the pre and power.
     
  3. pullagnm

    pullagnm Member

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    JJ's in the power section!
     
  4. M I K E D.

    M I K E D. Supporting Member

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    some of the folks around here dig the Brimar NOS 6v6's in DRRI's; usually available from KCA tubes. the proprietor is a member here and is usually very helpful in threads like these if you do a search you can find a lot of info -or- check out his site it has good info on these topics - highly reccomended.

    a lot of folks also prefer a different speaker than the stock jensen- I ve heard a Cannibus Rex is real nice.

    best of luck!
     
    Last edited: Aug 31, 2008
  5. sinner

    sinner Member

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    In my reissue:

    1. JJ's all around
    2. Weber Copper Cap Rectifier (adds punch, and a bit more headroom)
    3. Weber 12F150 Ferromax speaker
     
  6. 5E3

    5E3 Member

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    You can get a power tube socket like this from Eurotubes.com or Weber (I got mine for Eurotubes) and plug it right into your multimeter:

    [​IMG]

    About 20~22 mili-amps is what you are shooting for. There is a bias trim pot just recessed behind the power tubes, takes a small standard head screw driver. There are some How-To bias videos on the Eurotubes.com site, and one example is for Fender. It is very easy to do.

    I put new Tung Sol power tubes in my DRRI and have been very happy with them.
     
  7. BigPapiFan

    BigPapiFan Member

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  8. Presc

    Presc Member

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    I've got JJs in mine except for a NOS tube for the tremolo...I'm not sure which as they were put in by the previous owner. I haven't had to swap yet as it sounds good to my ears.

    I don't jumper the channels, but I recently built myself a true bypass A/B box based off the schematic found on the Fulltone website. I use the vibrato channel for cleans and light dirt as I find it a bit glassier and more open (plus the verb is nice), but the normal channel has more clarity for the higher gain settings esp. at low volume (using pedals, an OCD and Barber Direct Drive) so I bounce back and forth depending on what I'm using. Definitely a cool way to run the amp.
     
  9. Deadduck

    Deadduck Member

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    Ditto on this. Mike, aka Blue Strat, is the man to buy from, and his website is a very good guide. Tung-Sol Reissues are supposed to be a very good choice for new production 6V6's.
     
  10. Jack Dotson

    Jack Dotson Supporting Member

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    How do you know if a 12AT7 is balanced?

    BTW, a friend gave me an old GE-5751. I put it in V1 and the difference was huge. The 1st channel was a little smoother than the 2nd to start with, but now it's just incredible.

    I also tried a GT 12AT7C that I had as a spare in V3 to see if it would cure the slight crackling I was hearing when the re-verb is used. It made matters much worse. It's actually labeled GT 12AT7C. Is this different than a standard 12AT7?

    Thanks to all of you guys for you inputs thus far. The links have been very helpful. I've been on the amp/pedal go round for a long time (I'm getting off topic here, but wanted to share some things) and the best move I made was buying a T.C. Electronics Nova system. Pretty much everything I need in one pedal. Unlike most, if not all, multi-effects units, every effect is very good and useful. Not true bypass and not totally transparent, but I don't care, it sounds great.

    The 2nd thing I did right was trading a tele for the DRRI. What a great little amp and the perfect platform for good pedals. I can see why so many people love this amp. I figure once I get her to full potential she'll be a beast. BTW, I have yet another question. Have any of you converted yours to PTP? If so I'd like to hear what difference it made, who did the conversion and what it cost?

    Lastly I want to share with you an amp experience. I ran across a Black Star Artisan A-15 1X12 combo the other day while doing some shopping at a GC in San Antonio. I knew nothing about these amps, but it was expensive and the build quality was obviously exceptional, so I took it for a run. Wow! What an amp. Maybe the best I've ever tried. Two great amps in one really. I want one bad! :drool
     
  11. rkymtnhi

    rkymtnhi Member

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    ...for a different sound, try using el-84s via yellow jackets... your DRRI will really chime!
     
  12. BigPapiFan

    BigPapiFan Member

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    I test both triodes with a tube tester. You can also buy balanced tubes.

    Roger that on the GT in V3. My understanding is that V3 in Fender amps is very demanding. I use a Mullard cv4024 there now but I have tried RCA 12AT7's and they sound great there as well. Almost any old-stock tube I put there sounded better than the stock Fender GT. This includes the GE 6201/12AT7 (of which I have a bunch).
    I have been very fortunate in that a friend gave me a stash of used and NOS tubes from an electronics shop (and lent me his tester!), so I have been able to try quite a few. My experiences:

    V1 and V2: the Mullards I have in there sound the best of the tubes I presently have.
    Close 2nd-place: RCA 12AX7, Brimar 12ax7, USA Tung-Sol 12AX7.
    Strong 3rd place finishers: Sylvania 12AX7A/Ecc83/7025, GE 7025, GE 12AX7A.
    Lower gain: GE Five Star 5751, Raytheon 5751, GE 6072/12AY7.

    V3: Sweet: Mullard and Brimar cv4024, RCA 12AT7 black plate.
    Good: RCA grey plate 12AT7, GE 6201, USA Tung-Sol 12AT7, Amperex 12AT7.

    I haven't tested too many in V4 - V6. The RCA 12AX7 in V4 and the 12AT7 in V6 are fine.

    I bought the Jan Philips 6V6GTs from Penn amplifiers through Ebay and they were such a marked improvement over the Ruby Tubes that were in the amp when I bought it that I just stopped looking around. Apparently there are better.
     

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