TOS next build?

[dennyg]

Hey guys - I'd like to do a pentode pre-amp for next build.  Tubenit's TOS gets great reviews on here.  Let me know your thoughts:
* Any better ideas for a pentode pre build?
* This would also be my first PP build - want to use 6V6 though as i'm hooked on small 20Watt amps with the various SE amps I've done.  Has anyone used 6V6 with this pre-amp?  If not I plan to use the PA schematic from Hoffman's 6V6 Plexi
* I'm also hooked on old-school term strip building, using gothic ring layouts. Does anyone have a term-strip layout handy?
* Thinking about trying a toroidal PT from Antek.  thoughts?
 
Denny

[sluckey]

The TOS is a great choice. If you like a Voxy sound then consider this simple Dual Lite. You could easily drop the Marshall preamp and just do this as a Vox AC-15 Lite.

     http://sluckeyamps.com/dual_lite/dual_lite.pdf

[tubenit]

All good choices, IMO & you can add Geezer's HoSo56 with 5879 V1 preamp tube.  Another proven build.

The TOS is somewhat complicated for a 1st push/pull build.   I might lean towards Sluckey's idea or the HoSo56 IF you're not ready to take on a complicated build with relay channel switching etc .......   

Sluckey always has great info, schematics and layouts to guide you thru the build.

with respect, Tubenit

[dennyg]

hey guys thanks for the tips.  i'm ready to take on a bigger challenge.  i've built four SE amps over at AX84, all two channel with foot-switchable relays, and 3 high gainers which i learned a ton about proper layouts and grounding schemes.  i like that the TOS is cathode bias so i don't have to deal with the complexities of fixed-bias yet.
is there a BOM anywhere?  i'll also be using term strips so if anyone has a term strip layout would be useful otherwise i'm ready to start drafting that up.

[tubenit]

Given your experience includes relay switching and high gain amps and being attuned to the need for good layouts, I'd say you should be up for building a Tweed Overdrive Special.
 

There is a BOM here along with an ExpressSCH "editable" schematic and layout: 
http://el34world.com/Forum/index.php?topic=9636.0

IF there is not a paralleled terminal layout on that thread, I may have one available at home.  FYI,  Hoffman does sell a layout board for the TOS.  And that layout board is a good proven design.

IF you use a PT that is 275-0-275 or 300-0-300  with 140ma (or more) and then go cathode biased, you should be able to change between 6V6's or 6L6's/5881's without rebiasing.  And I'd advise using a tube rectifier socket so you can use a 5Y3GT, 5V4 or 5U4, or a GZ34 or solid state rectifier plug in.

With respect,  Tubenit

[dennyg]

I've decided to have this be my first PP amp and like the simplicity of cathode bias before I take on a fixed-bias design.
I'm going to run 6V6's and use an 18Watt OT - are the component values for the PP section the same as for the original TOS schematic for 5881's? 
You mentioned that 6L6's/5881's could be used but I'd think they'd blow an 18W OT - they're like double the dissipation of a 6V6?

[dennyg]

I think I found what I need for 18W 6V6 PA for the TOS - the Stout is a cath biased 6V6.
I'm using a Hammond 270EX 275-0-275 144ma PT which should have plenty of juice yes?

[tubenit]

Hammond 270EX 275-0-275 144ma PT which should have plenty of juice yes

Yes, that should work fine for 6V6's.  You can use a 5Y3GT, 5V4, GZ34 or solid state rectifier.   You may be able to even run 5881's as well?  You could install 5881's and then see if the heater 6.3v voltage drops compared to the 6V6's?  If not, then you may be Ok even running 5881's? The Hammond PT's are under-rated & overbuilt, IMO. 

The old Silvertone tube amp had very undersized OT's and some of them really sound great.

With respect, Tubenit

[mozz]

Question on the dual lite. Can i jump the channels if i use mixing resistors and send that into the top of the PI?

[sluckey]

Yes. Don't forget to ground the coupling cap for the bottom input of the LTP if you do this. Or you could use the bottom for some NFB and a presence control. Not sure how any of this would affect the sound of either preamp. If you try this please give us a report.