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Thread: 7868 Power Tubes?

  1. #1
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    7868 Power Tubes?

    I have a wurlitzer tube amp with 7868 power tubes. Is their a guitar amp that used this type of tube or could i use different power tubes with the 7868 output transformer setup? Just trying to find a new project.

    thanks
    BD

  2. #2
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    The 7868 is identical electrically with the 7591A. They're in between a 6V6 and a 6L6GC for power output, and they have a lot of gain for a power tube...almost as much as n EL84, so the preamp can be low gain and still drive them well. They're my favorite power tube personally. EH makes a new 7868 that sounds good, though NOS of course sounds better. The transformer set will work fine with the 7868, 7591A, or even the 6L6GC for a slight mismatch. The 7591A's were used in a lot of Ampeg stuff so you can look to those for circuit ideas, though they ran them conservatively and you can get a lot more out of them if you run them like Fender ran the 6L6GC.

    Greg

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    Thanks Soundmaster

    I want sure about the tubes. Maybe i build a fender curcuit around them and see how it sounds.

    Thanks
    BD

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    A lot of 60's era Bogen amps used 7868's. I like them--maybe just because they have their own sound, which isn't a 6v6, 6L6, el34, etc.

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    7868

    Hi, There was a company named Sound Musical Instruments out of NY that made tube guitar amps in the 60's that were based on the 7868 tubes. That was the first amp I bought, back in '81. I since then converted the amp head into a 1-12 combo. The 7868 tubes sound very well. clean headroom with nice break up when turned half way up. It is a very gig worthy amp with the pair of 7868 tubes. I retubed it about a year ago the EH tubes, which sound good, see pics,
    Attached Thumbnails Attached Thumbnails img_0155.jpg   img_0157.jpg   img_0158.jpg  

  6. #6
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    Cool amp Gerald

    Thanks for the pics and info

    Baddog

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    Quote Originally Posted by Gerard View Post
    Hi, There was a company named Sound Musical Instruments out of NY that made tube guitar amps in the 60's that were based on the 7868 tubes. That was the first amp I bought, back in '81. I since then converted the amp head into a 1-12 combo. The 7868 tubes sound very well. clean headroom with nice break up when turned half way up. It is a very gig worthy amp with the pair of 7868 tubes. I retubed it about a year ago the EH tubes, which sound good, see pics,
    First post here!
    Great pics Gerard.
    I have a Sound Amp as well. It is a X-305-R. It has a 15" Jensen speaker in the combo cabinet.
    Do you have any additional info on these amps? I have been trying to find more info for a while. I bought mine for $5 at a garage sale. I am going to retube, clean pots and see what it sounds like. At this point it squeals and when it is not it sounds like poop.

  8. #8
    Member Gerard's Avatar
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    $5 is a great but for that! Sorry, but I don't have any info on these amps. I do see them on ebay for around the $100-200 range. It seems that most of them I see for sale are usually in NY where they were made. Mine is a model 900 which is a funky looking amp head with reverb and tremolo. I turned it into a combo. It also seems that all the other Sound amps I have seen are all pretty similar with there tube compliment. Let me know if you find anything out about these amps. They sound very good with lots of volume, Thanks

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    Here's a clip of a 7868 x 2-- 35 watt modded Plexi circuit head i built with Bogen CHB35A iron and chassis---- it orig ran 7868's----i've used the EH 7868's in some amps and they are pretty good sounding----- the 7868's in the clip are Sylvania's...........gldtp99


    Clip--- click on "Mule 35 Plexi"-- http://www.soundclick.com/bands/defa...?bandID=741589

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    Quote Originally Posted by Gerard View Post
    Hi, There was a company named Sound Musical Instruments out of NY that made tube guitar amps in the 60's that were based on the 7868 tubes. That was the first amp I bought, back in '81. I since then converted the amp head into a 1-12 combo. The 7868 tubes sound very well. clean headroom with nice break up when turned half way up. It is a very gig worthy amp with the pair of 7868 tubes. I retubed it about a year ago the EH tubes, which sound good, see pics,
    Nice amp Gerard.

    I have the same head (still in head form) I picked up at a flea market 20 years ago without any tubes in it.



    Have you ever found any technical information on them like the schematics?

    Also, I've heard a lot of rumors/comments about Sound being an Italian company. Was there another Sound amp made in Italy, or did this company build anything over there?

    It's hard to find info on Sound amps online.

  11. #11
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    Hi,

    I saw the thread on the 7868 power tubes. I have owned a Sound X505R Amp since I was 16 many years ago. Here are scans of the schematic I have for it.


    Andy
    Attached Files Attached Files
    Last edited by Andy B; 05-27-2010 at 03:04 AM.
    Jazz P Bass likes this.

  12. #12
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    I have Precision Electronics PA head that uses 7868s and makes a fine guitar amp in stock configuration. Prices that I've seen are pretty crazy - I wouldn't chase them.

    Since you already have a presumably well designed output section with a well chosen transformer in the wurlitzer - maybe try beefing up the front end

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