Hi Gain SE Amp

[TIMBO]

Hi guys, On a bit of a hi gain kick at the moment.
Looking at these circuits for some hi gain blues rock.
After doing the 10w SLO clone and the trouble I had with the SLO preamp slamming the little output valves (some more tweaking has got it in a good place  )
I'm hoping to reduce the output  by using the SE and maybe the EL84 will handle the ABUSE.

[DummyLoad]

can't help but think that a switch to a grid with that much gain on tap isn't going to be anything but trouble. cap switching the cathodes like that is going to POP LOUD.  put a 47K-100K under each cap and use he switch to short across the resistor to enable. that's A LOT OF GAIN. 


--pete

[bmccowan]

I find this page an interesting discussion on SE- high gain amps:
http://chasingtone.com/dvnator/the-seplex/
I myself have not found SE EL84 amps to sound very pleasing, and the higher the gain, the more harsh they sound to my ears. I started playing around with them a few years back, following somewhat the Weber Smokin Joe 1 schematic. Finally ended up switching to a big bottle.  The best sounding SE amp I've built was a conversion of a SE Bogen CH8. 6AV6 - 6SJ7 - 6L6. I think there is a Jack Hester thread with a similar conversion of that Bogen. There may be some interesting thoughts in that thread.

[DummyLoad]

here ya go. steel toe boots a must. hernia free a big +.


--pete

[TIMBO]

MAN, that is some beast....

[TIMBO]

Hi guys, Keen to hear this one, so shed got a workout today.

[TIMBO]

A little progress...

[sluckey]

Coming together nicely. 

[Ritchie200]

Pete,


I expect to see your build progress on the Toe Crusher shortly?


Jim

[DummyLoad]

Pete,


I expect to see your build progress on the Toe Crusher shortly?


Jim

mr. jimbob: sorry to say that i'm not much a fan of the soldano tone, so not building that. i did have a request to build a SP77 for an acquaintance and why i drew up the preamp plans - nothing materialized. i have other plans for the toe crusher/hernia discovery tool so stay tuned.

 

--pete

[TIMBO]

Wiring complete......

[TIMBO]

Hi guys, Pushing on with this one.......
I've worked out a switching matrix, although I'm not sure this how it's meant to be, it works for me.
I'm wanting to use the heater power to supply the bridge rect as per the Hoffman site.
I have added two 100r resistors for the artificial CT even though the PT had a centre tap for the heaters ( the voltage either side of the CT were very uneven)
I had the heater CT connected to the cathode of the power valve to elevate the heater supply.
My question is....
Now that the heater supply is elevated is it OK to use the heater supply to power the bridge rect to power the relays.
Thanks

[shooter]

is it OK to use the heater supply to power the bridge rect to power the relays.

did you set it up so the bridge and everything in the switching circuit was "isolated", NO ground to chassis on the DC side of the bridge or relays?  If so then it was already "floating".
the AC into the bridge doesn't "know" a DC reference or ground reference.  The DC - out off the bridge becomes "ground" for that circuit.  As long as that ground doesn't come into contact with real ground everything's happy as a clam

I think 

[kagliostro]

Ciao TIMBO

OK, you are already on the route, however maybe you can find something of interesting here


http://el34world.com/Forum/index.php?topic=12774.msg119114#msg119114





--


On that thread there is (at post #4, by Sluckey) a link to a .pdf file that is out of service, here attached you can find the .pdf file


Franco

[nandrewjackson]

Shooter + 1


Your new "ground" at the bridge rectifier feeding off of the heaters IS NOT the same as your chassis ground,  so keep them separate. 

[TIMBO]

Hi guys, I'm getting some what PISSED off with the relays I've been using.
I built a little circuit board for the relays and all works as it should to a point.
I'll also add that the foot pedal will have two switches one for each relay.

Pretty simple....
But the drop in volume when RLY1 is activated (47k grounded)is very minor.
If I have RLY1 as it is on the schematic I can ground the 47k with a jumper and get the desired drop in volume.
So I'm rather convinced that the RELAYS that are being supplied these days are CRAP or I'm doing something wrong.
My next move is to remove the relays and wire the footswitches the same as the relays.

[TIMBO]

Hi guys, Moving this one along.....
Cab is mostly done..






Foot switch completed..


And replaced the EL84 with a 6V6GT

liking the 6V6 much better

[kagliostro]

WOW !!! that tolex is Fantastic TIMBO

Franco

[Colas LeGrippa]

definitely that the 6V6 will sound better !


very neat job Timbo ! the two colours Tolex look awesome !

[jojokeo]

Timbo,Your build quality has improved a lot! I'm thinking of the Beverly Hillbilly's opening song..."Black tweed, Texas tea..." Nicely done mate! Hurry up so we can hear what she sounds like!