2204 Tube Rectifier

ironskull · Post by **ironskull** » Mon Nov 21, 2005 2:40 pm

I am considering a switch to tube-rectification for a 2204. Does anyone have any insight to this, i.e. which rect tube would work better than others, other mods necessary, etc? I was thinking about using a GZ34 type tube. Would it just be a matter of cutting out the diodes and appropriately wiring a tube socket?
Thanks

Billy Batz · Post by **Billy Batz** » Mon Nov 21, 2005 2:48 pm

Well tube rectos run on 5v so youd need a 5v filament power tranny. Im not sure what you want to do this for but putting a 470ohm/5W resistor in line after the choke simulates the resistance sag of a tueb recto.

Flames1950 · Post by **Flames1950** » Mon Nov 21, 2005 3:54 pm

The GZ34 would be the way to go. If you choose to do this I think I'd see if the tube socket would mount up in one of the two filter cap holes by the power tubes. Then I'd move one of the cans under the chassis somehow -- I'd probably make a custom mount to bolt onto the tranny bolts, then bend up at a right angle to hold the cap can horizontally, so there's no extra holes to devalue the amp any more than necessary.......
That leaves a non-intrusive way to get a 5V tap, I don't know what's out there for PT's that would do the job and fit your existing holes......

Billy Batz · Post by **Billy Batz** » Mon Nov 21, 2005 4:01 pm

You could bolt the can to the side over the PT like JTM45's.

Flames1950 · Post by **Flames1950** » Mon Nov 21, 2005 4:42 pm

Yeah, I just hate to add more holes.

Billy Batz · Post by **Billy Batz** » Mon Nov 21, 2005 4:55 pm

Yeah its original isnt it? Im just affraid bending the can mouting rings so you can mount it inside will eventually bend down again and stress the solder joints since its hanging upside down. Unless you tie it down with something for extra-support. Im curious why do this with a 2204 anyway? What are you trying to acheive? The sag resistor thing is a good thing to try if thats what your after.

scottosan · Post by **scottosan** » Mon Nov 21, 2005 5:50 pm

ironskull wrote:I am considering a switch to tube-rectification for a 2204. Does anyone have any insight to this, i.e. which rect tube would work better than others, other mods necessary, etc? I was thinking about using a GZ34 type tube. Would it just be a matter of cutting out the diodes and appropriately wiring a tube socket?
Thanks

Do not use the GZ34. with a capacitor input filtering, you are limited to no more than 60uf on the first cap before the choke for a 5ar4/gz34. You currently have 100uf and can easily go through tube rectos quickly.

daniel · Post by **daniel** » Mon Nov 21, 2005 6:09 pm

you could also use a webber copper cap since they don't need need the filament power.

ironskull · Post by **ironskull** » Tue Nov 22, 2005 3:33 am

...Interesting stuff. The amp is not an original Marshall, it is a homemade design based off the 2204, so keeping resale value is not really a concern of mine. I will consider this sag resistor idea more; if that works, it sounds a lot cheaper, easier, and more reliable.

That was my first question of what is sure to be many in this forum. Thanks for the great input!

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2204 Tube Rectifier

2204 Tube Rectifier

Re: 2204 Tube Rectifier