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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

first tube project

Spooky1

Member
2005-08-11 11:30 am
Looking for a reasonably simple SE design to build as a first project.
Have some XP with electronics and diy, and am currenly on a learning curve re-building and designing tube circuits - not yet knowledgable to design own, but ready to build one (especially as my power amp has been nicked by scrotes).
have a budget of around £300 to spend over here in UK.
Power not too important as it will be driving some Rhedeko 115's with a sensitivity of 96/dd - but will probably need 5+ watts to really move air.Would sooner have sweet lo-power rather than high-grunt!
Would prefer schematics for amp AND psu - any ideas?
Thanks in advance chaps,
Spooky1
 
Do a search here for Mikael's SE KT88 schematic. I built this as a pair of monoblocks and have been very happy with the result. I had been using them with a preamp but recently gave a passive pre (just a volume pot and source selector really) a try and find that I like that combination just as well.

I used James 6123HS OPTs and Hammond iron for the PTXs and chokes.

Here is a drawing for the PS I used with mine. Note that I built monoblocks so there are two of these power supplies. The Hammond PTX I used doesn't have the current capacity for two channels so you would need to beef that component up. The rest should work I think.

Oops, I forgot. Mikael was estimating 4-5 watts per channel. I hooked up the scope a couple weeks ago and ran some tests with mine and I'm getting somewhere around 6 watts.
 

Attachments

  • kt88 power supply schematic.jpg
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Yup, go for this one!

Sweet sounding, highly detailed, excelent sonics, though i need a preamp on some CDs (that's a different story), can be built in an afternoon, as long as the chassis is ready :p
I'm using a Valvo E88CC (if, like me you have difficulty in sourcing the 6N1P), and it gives a little "fatter" sound, unlike Philips E88CC.
The only mod i did to Shermans (thanks ;) ) PSU (powering both channels) was replacing the 100uF cap for a 220uF - 5mV ripple!

Cheers!
 
No changes made, Sherman.
I asked for help at Edonion to see if there was any need to change components on the E88CC side, but they assured me i wouldn't need to.
So far, so good. I tryed a cheap PCC88 first, but the gain was a tad low due to a bit starved filament. Happy now, though :D

Happy mod Sherman!