Heathkit EA-2 mod question

[PabloL]

A quick question for the tube gurus here. I was thinking of modding a pair of EA-2's (see attached schematic) for a fun project. First off I was thinking of removing the tone controls, basically going from C21 straight to pin 8 on the 6AN8 erasing everything between (R15 to R18 and C14 to C15). Would this be ok? The second thing would be to remove the selector switch and the Xtal input and replace it with an on/on switch (Tuner (Pin 7) and Phono (Pin 4) to C9). Lastly I would change the Vol pot to a dual ganged stereo pot and control the volume from one unit. These are cheap so I'm not too worried about hacking them up, likely I'd make a new front plate. I'm thinking I would also need to change value of the divider after the tuner input to use with a CDP?

[soundmotor]

A quick question for the tube gurus here. I was thinking of modding a pair of EA-2's (see attached schematic) for a fun project. First off I was thinking of removing the tone controls, basically going from C21 straight to pin 8 on the 6AN8 erasing everything between (R15 to R18 and C14 to C15). Would this be ok?

The second thing would be to remove the selector switch and the Xtal input and replace it with an on/on switch (Tuner (Pin 7) and Phono (Pin 4) to C9). Lastly I would change the Vol pot to a dual ganged stereo pot and control the volume from one unit. These are cheap so I'm not too worried about hacking them up, likely I'd make a new front plate. I'm thinking I would also need to change value of the divider after the tuner input to use with a CDP?

For the direct mod you need to tie pin 8 to ground via a resistor. I think though what I would do is rebuilt it as a UA-1/UA-2 as it uses the same output & power transformer set.

UA-1 Schematic (http://www.nijnkonijn.nl/machmat/schema/power/ppp/heath.gif)

[PabloL]

That would make things much simpler on one hand, but it would be more than a simple rewire. However it would probably allow me to use a better phono/preamp. Thanks for the suggestion

[radioactive]

i'd do what soundmotor suggested and redo them as separate monoblocks using the ua1/ua2 schematic.get yourself some nice chassis order up some new caps etc(they'll probally need them anyways unless recently rebuilt)and away you go.i'm actually going to do this with a sa2 that i have sitting on the shelf one of these days.

[dnewma04]

I am planning on doing something just like that with a pair that I have. The ugly little brutes will be much better off on a new chassis. :)

[soundmotor]

i'm actually going to do this with a sa2 that i have sitting on the shelf one of these days.

That will be a ripping little amp too!

I have (1) EA-2 (or EA-3, can't recall) and need to find another with matching transformer set. (I sold off my AA-61's (last version of UA-1/UA-2) way back when in a weak moment and have always regretted that. They sound so fine.) For my mods on the EA-2's though I'd planned to just saw off the front portion of the amp as the output & power supply occupy the back. That would leave me with a nice beefy amp-only chassis that I would put a hardwood border around in typical DIY console amp fashion.