Ceriatone Forum

Custom amp building, Prototypes and other amps => Discussion => Topic started by: sinrman68 on February 08, 2009, 09:02:11 PM



Title: Gotta question for those who may best be able to answer...
Post by: sinrman68 on February 08, 2009, 09:02:11 PM
Ok, here's my issue...I am looking at acquiring one of the 36 wat Ef-86 marshall clones.  I am interested in learning how to build, but am way out of my league here and need some help!
 What I'd like to do is have the 18 watt (50% power) setting power two El-84's (the amp has 4x El-84's).  That way at half power I enjoy all the breakup and compression that the El-84's have to offer.  I would like to have the other two El-84's replaced by 2x 6v6's.  That way, in the full power mode-at 36 watts- I've got the 2x El-84's going at saturation and compression...and the 2x 6v6's will be going as well.
Trouble is...I'm so new to this, I don't even know where to begin analyzing the things that could go wrong.  I spoke with nik about sending me the Pkg 1 kit and requested info on the transformers...thinking I'd save a bit of money buying these stateside...when I saw the Mercury magnetics mod for the Epiphone Valve Junior.  They upgrade the OT/PT/and choke...and add a flippin 6v6 to the power stage.  Not only do I think the mod is the cats meow-I'm tryin to figure out how to do this with the future 36 watt unit.
I wouldn't be so boo-hoo'd if I had a place to open up some big tubes...so I'm stuck in the low watt range.  I am simply not that into the 4x El-84 poweramp section having had a Carvin Belair 2x12 50 watt unit.  Clean-it was heaven sent !!!
The problem was when you added a little bit o' balls-it just smegma'd right out.  I'm thinking the 6v6's will help it retain some control and harmonic saturation without goin to pudding!
Any help,  hint's, or even a "what in the hell are you thinking?" are greatly appreciated.
John Patrick


Title: Re: Gotta question for those who may best be able to answer...
Post by: wyatt on February 08, 2009, 09:26:46 PM
6V6's go "to pudding" a lot faster than EL84's.  EL84's are generally tighter and more focused; 6V6's are middy, but get loose in the bottom end their breakup is less tight, more big and open (lo-fi, brown tone).  obviously with a little attention to pre- and power-amp design, either tone an be tweaked.  What 6V6's will give is a tone a little more traditional Tweed/Marshall-y, more mids, less articulation, mushier breakup.

Power requirements and output are very close for wither to.  They can use the same power transformers (no significant change in current draw) and output transformers (primary impedance will remain the same). Really all you are doing is finding room for the significantly larger octal tube sockets and rewiring for the change in pin layout. 



Title: Re: Gotta question for those who may best be able to answer...
Post by: sinrman68 on February 08, 2009, 09:52:27 PM
wyatt...thanks for getting back to me-what do you suggest?  I was erroneously under the impression that the el-84's were softer than the 6v6...if i wanted to accomplish my goal-would you suggest looking at adding a different tube?  a set of kt-66's or 6l6gc's.  I am looking at harmonic resonance at the 36 watt setting.

Any suggestions greatly appreciated


Title: Re: Gotta question for those who may best be able to answer...
Post by: yumchild on February 10, 2010, 06:49:48 PM
... I spoke with nik about sending me the Pkg 1 kit and requested info on the transformers...thinking I'd save a bit of money buying these stateside...when I saw the Mercury magnetics mod for the Epiphone Valve Junior.  They upgrade the OT/PT/and choke...and add a flippin 6v6 to the power stage.  Not only do I think the mod is the cats meow-I'm tryin to figure out how to do this with the future 36 watt unit....

Related newbie question ...
What set of transformers would be a state side option for the 36 watt?  I wouldn't have considered it but the near $100 shipping increase makes me wonder what other options are out there.  If the price comes out the same as what Nic offers, is there a quality difference?