2Watt Sub Miniature Plexi

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UR12
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Re: 2Watt Sub Miniature Plexi

Post by UR12 »

I haven't had any trouble at all with hum. I put a grond lug on the
screw holding the power recepticle to the chassis and run an ac ground from the
power jack to the lug and ground both the CT for the heaters and HV there.
I then connect a wire fron the ground on the power jack to the PS
board. I'll also sed if I can find a pic or there should be a hoid pic in the
LD build manual posted somewhere on this site in the Lil Devil thread.
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JazzGuitarGimp
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Re: 2Watt Sub Miniature Plexi

Post by JazzGuitarGimp »

Thanks Dana. I'll rewire my grounds as you've described and see how that goes. How about my voltages, anything look out of the realm of normal? The cathode voltages on V1 look low for a modern day guitar (I think). Please let me know.

Many thanks,
Lou
Lou Rossi Designs
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UR12
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Re: 2Watt Sub Miniature Plexi

Post by UR12 »

JazzGuitarGimp wrote:Thanks Dana. I'll rewire my grounds as you've described and see how that goes. How about my voltages, anything look out of the realm of normal? The cathode voltages on V1 look low for a modern day guitar (I think). Please let me know.

Many thanks,
Lou
I'll have to do a voltage check on the one I have here. I have a guitar show on sat and am working like crazy to get ready for it so it may be after this weekend. With that said your voltages don't look out of the ordinary. Just remember these small tubes aren't rated for the higher voltages of their cousins
MCK
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Re: 2Watt Sub Miniature Plexi

Post by MCK »

Hi Dana, just bumping this thread up to see how things are going with the MicroPlexi. Hope all is well and that you are getting closer to production runs. Let us know when you can please. Thanks much!!!
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JazzGuitarGimp
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Re: 2Watt Sub Miniature Plexi

Post by JazzGuitarGimp »

I need to get back to my build. Still has hum issues, but I've been very busy lately....
Lou Rossi Designs
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UR12
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Re: 2Watt Sub Miniature Plexi

Post by UR12 »

Hi guys. I've been sooooo busy the last few months with VVR sales and builds that I have had very little time to check in on the forums. That's a shame as I miss hanging out here with you guys. In my spare time I've been playing with my band of old guys and working on our PA and lighting system.

Recent clip of a benefit we played back in Feb

www.youtube.com/watch?v=EeKhkXL9Ztg

I have basically had the Microplex on the back burner and haven't offered any for sale yet. So how is everyone coming with their builds. Any news , suggestions or problems with the Microplex amps out there?



:lol: :lol:
skyclmbr
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Re: 2Watt Sub Miniature Plexi

Post by skyclmbr »

Hello Dana,

My amp is still chugging along fine and sounds great. I still owe the community the sounds (of my bad playing) through a 4x8 and a 1x12 cab, just to see what the 4x8 sounds like.

I haven't been able to go in yet and make the fix to the PI stage. When I do that, I might make a couple switches and another "daughter board" that would make it switchable to a JTM45 via:

Switch the cathode bias circuit on V1 to JTM45/Bassman
Switch the cathode cap on V2 to JTM45
Change treble/slope resistor on tonestack to JTM45/Bassman
Change the feedback resistor to JTM45
Change the filter caps to 47 uF (JTm45)

I think I can do this with 2 4PDT switches on the back of the chassis and a daughter board. My only concern would be with the switching on the rail, my plan was to have parallel 47 uF caps in place of the 100 uF caps on the rail and then switch half of the 47's out to convert it to a JTM45 power supply. That'd be a fair bit of juice running through the switch? So I'd assume I'd need one rated for 500v or something.

Anyway, if anyone has any interest in that or suggestions on how to make it work. The base amp right now sounds so good I kind of don't want to change it though!

The band sounds great Dana!

Thanks Dana,
Bryan
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drhulsey
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Blowing fuses in Lil' Devil

Post by drhulsey »

I finally got around to finishing the Lil' Devil. Attempting start up, I have 120V at the mains input. I am blowing fuses every time I turn it on. Any common causes?
Tim

In case the NSA is listening, KMA!
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Colossal
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Re: Blowing fuses in Lil' Devil

Post by Colossal »

drhulsey wrote:I finally got around to finishing the Lil' Devil. Attempting start up, I have 120V at the mains input. I am blowing fuses every time I turn it on. Any common causes?
Dr. Hulsey! Good to see around again. It's been a while.

Perhaps a reversed polarized electrolytic cap?
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drhulsey
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Re: 2Watt Sub Miniature Plexi

Post by drhulsey »

I've been playing a lot and not building much. It's good to be back. I am tracing all the wiring and will chek the polarity on the caps, as you suggested.

Thanks!
Last edited by drhulsey on Sun Jun 09, 2013 10:12 am, edited 1 time in total.
Tim

In case the NSA is listening, KMA!
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drhulsey
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Re: 2Watt Sub Miniature Plexi

Post by drhulsey »

Diode in the PS was reversed :oops: I get 175V at B+, but it only goes down to 117V. On the bias voltage, it ranges from 25-34V with adjustment of the bias pot.
Tim

In case the NSA is listening, KMA!
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Colossal
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Re: 2Watt Sub Miniature Plexi

Post by Colossal »

drhulsey wrote:Diode in the PS was reversed :oops: I get 175V at B+, but it only goes down to 117V. On the bias voltage, it ranges from 25-34V with adjustment of the bias pot.
That'll do it :wink: No more blowing fuses?
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drhulsey
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Re: 2Watt Sub Miniature Plexi

Post by drhulsey »

The instruction manual says the B+ should go down to 50 and the Bias should go to -50. I'm not hitting those parameters.
Tim

In case the NSA is listening, KMA!
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drhulsey
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Re: 2Watt Sub Miniature Plexi

Post by drhulsey »

If anyone is listening at the NSA, you're welcome tomchime in, too! :D
Tim

In case the NSA is listening, KMA!
Bob S
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Re: 2Watt Sub Miniature Plexi

Post by Bob S »

I'm sure they have a budget just for us.
We need to be watched.
Good to see you back Dr Hulsey !!!
Why Aye Man
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