2Watt Sub Miniature Plexi

[drhulsey]

Looks like another great project

[MCK]

Just in time for the long winter nights eh?

[UR12]

Just in time for the long winter nights eh?

I was up till about 2am this morning soldering. I'll try and post some more pics. Barring any unforseen circumstances I should have the first prototype operational by this weekend. I had thought about using some mustard caps on this one but I don't have a hugh stash and want to save them for my 100 watt build I have coming up next. I decided to go with the tropical fish again as both the Mustards and the tropical fish were both from Mullard anyway.

[Richie]

And if this amp turns out like it should, i've planted the seed for another idea along these lines, but i'll wait to let
Dana fill you in after he gets this amp done. Just an idea i thought alot of people would want.
I know i wouldn't mind having one myself.

[Cliff Schecht]

Was the board in that picture etched or milled? We have a PCB milling machine up at school and I've absolutely refused to use for the past 5 years, my etched boards always look better.

[UR12]

Was the board in that picture etched or milled? We have a PCB milling machine up at school and I've absolutely refused to use for the past 5 years, my etched boards always look better.

I don't have access to a milling machine so all my boards are etched. I just use press and peel and it works as good s I need for prototypes.

[UR12]

Here is a few more pics. I should have it fired up today. I have alll the power supply voltages verified but found a mistake on the board I have to correct before I can fire it up. Just have to move a couple of resistors and a cap and cut a trace and add a jumper. I already have it corrected on the board layout and have made a couple of other revisions. Back to the soldering iron

[dayn]

Looks great. Did you ever decide what to do about having two inputs that can be linked? Can't wait to hear the report once you fire it up!

[Structo]

Does leaving most of the copper on the backside help with noise reduction as in shielding?

[gearhead]

Crickee, that is so cool. 90% of my playing time is with the Lil' Devil, and this one gives me the chills just thinking about it. Yes, there is a certain satisfaction with the whomp of a full-bore larger bottle amp, but I still need my eardrums.

Is this based on the KT-66 or EL-34 topology? Both are killer, but thought the later was more the Plexi?

Suggested mods: brite switch to emulate the Metal Panel-era tones. Love both, but there is something special about the MPs that are (imho) underappreciated.

[UR12]

Crickee, that is so cool. 90% of my playing time is with the Lil' Devil, and this one gives me the chills just thinking about it. Yes, there is a certain satisfaction with the whomp of a full-bore larger bottle amp, but I still need my eardrums.

Is this based on the KT-66 or EL-34 topology? Both are killer, but thought the later was more the Plexi?

Suggested mods: brite switch to emulate the Metal Panel-era tones. Love both, but there is something special about the MPs that are (imho) underappreciated.

Richie sent me a bunch of Marshall mods to try on the amp. This one is designed more like the 1987 actually with EL34s in mind. I did add grid stoppers and a resistor to drop the screen grid node about 5 volts.
It already has the stock Marshall Brite cap installed but it isn't switchable.

I also have a Micro Vox on the drawing board as soon as this one is finished that will have a 6205 subminiature pentode front end like the EF86 Voxes.

Looks great. Did you ever decide what to do about having two inputs that can be linked? Can't wait to hear the report once you fire it up!

I added a channel switch to switch the single input between chI, chII and Both. I am not sure I like not being able to mix different levels with the single vol control and the concentric knob dual pot isn't cheap so I may redesign the chassis and board and just seperate the vol controls into two different pots on the front panel. Hard to believe I can have a whole custom chassis laser cut cheaper than I can buy a concentric pot.

Does leaving most of the copper on the backside help with noise reduction as in shielding?

It can cut down on noise if it is done correctly. If not done correctly it can cause noise so it is kind of a tightrope that has to be walked. It's kind of like adding a bottom plate to a TW. This amp is completely quiet so far, no hum or hiss to speak of.

[MCK]

This is amazing. You're on a roll. Wreck, Plexi and then Vox... How about a mini ODS next? Hope you have a good stock of the sub-miniatures... Great going!

[Ron Worley]

Hey Dana, how about the.... well, never mind....

[LeeMo]

Looks great!
I think that I found Nemo.
Pretty caps!
LeeMo[/img]

[dartanion]

Looks great!
I think that I found Nemo.
Pretty caps!
LeeMo[/img]

Hey LeeMo,

Long time no threads! I remember chatting on 18watt years ago. What's happening brutha?