36 Watt ( long )

[PaisleyAmps]

Hi all ,

1st of all : great forum and an excellent site !
After building some Matchless and VOX inspired pre-amps in a couple of EL84 pp amps I really gotto try the Marshall one .
Right now I do have an old Eko SuperDuke over here with two 12AX7s and four EL84s , big choke , 2 inputs , 3 pots and aotput 350 Volts on the plates with cathode-biasing . Eko was an Italian budget-brand from the 60/70s and this amp does have a baxandall-a-like-tonestack ( don't like the voicing ) and/but the OT is sounding pretty good , really chunky .
1st I did have the idea to build something like an old VOX AC30/4 with the EF86-preamp but after hearing so much amazing results with the Marshall 18 Watt circuit I ( almost ) did change my mind .....
What about a "36 Watt" , the normal-channel into PI into four EL84s ? Any suggestions and/or experiences are welcome .

tia & kindest regards from Driebergen , The Netherlands

Chris

[markh]

hi Chris,

Welcome - I think a 36 watt would be an interesting experiment. Some folks have actually done 18watt builds using a more Vox-ish PI and have had good results as well. Try it out and see!

--mark

[MarkB]

I asked the same question a while ago. If you give each pair of EL4s its own cathode resistor, you could put a ground lift switch on one pair for half power. I may try it after I finish the AC15 I'm working on now.

MarkB

[PaisleyAmps]

Thanks guys !
This will be my first 18 Watt style amp so I do have a couple of questions before rebuilding this vintage-cheapo :
- does the 18 Watt have enough high-end to add a VOX style cut-control ?
- halfpower-switch or standby-switch ? ( the amp does have a ss-rectifier and no standby-switch )
- what "input-mode" is used more often : parallel or single ?

tia !

Chris