Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: taylorc315 on April 11, 2017, 12:27:50 pm

Title: Plexi 50 Question
Post by: taylorc315 on April 11, 2017, 12:27:50 pm
Just a quick question on the 50 watt Marshall I've built, what would it take to replace the EL34's to KT88's. I'm not sure what the correct voltage is that i need for the KT88's and not sure if the output transformer can handle them. I used the kit available from Hoffman Amps, any advice would be greatly appreciated.
Title: Re: Plexi 50 Question
Post by: shooter on April 11, 2017, 12:41:41 pm
Quote
what would it take to replace the EL34's to KT88's
the specs are close enough that with re-biasing they should fly, don't hold your breath on magic but maybe a nice smile
Title: Re: Plexi 50 Question
Post by: taylorc315 on April 11, 2017, 03:44:01 pm
Thanks Shooter  :headbang:
Title: Re: Plexi 50 Question
Post by: Ritchie200 on April 11, 2017, 11:06:58 pm
Oh, I'd say hold your breath!  Marshall made the Park 75 back in the early 70's which was a 50 with KT88's.  I played one at a music store back in the late 70's.  I think they wanted $200 for it - still a lot of jack back then, but man I should have bought it.  It reminded me of a slightly scaled back Hiwatt with that beautiful ringing high end but still enough low end grunt to move your pants.  This is why I love the KT88, it is such a musical tube that doesn't wimp out when the going gets tough.  The first link gives a little history about it - but I would not give any credence to the "Marshall made this hotter..." etc, etc....  The video at the bottom of that link does NOT sound like a real one.  That one sounds like it is in major need of a cap job.  The second youtoob link is about the current reissue and it nails THE tone.  I would hope your tube switch will yield this tone.  Post some clips when you make the change!  Welcome to the KT88 dark side..... :icon_biggrin:

Jim

http://www.vintageguitar.com/15454/park-75/ (http://www.vintageguitar.com/15454/park-75/)

! No longer available (http://www.youtube.com/watch?v=iEN_I531mr0#)

https://www.youtube.com/watch?v=1Q3RxpD_5KU (https://www.youtube.com/watch?v=1Q3RxpD_5KU)