Plexi newbie

MUGuy · Post by **MUGuy** » Wed Nov 11, 2015 7:48 pm

Well, I made the mistake of looking at this forum. In it, I found links to lots of tips on how to build a plexi's. Having been unable to afford one when I was a kid in the 80s, I convinced myself I owed it to myself to build one just the way I want. That is one that sounds in the range of early VH. I know that is a bit poser, but, hey, I am too old to care. I play music to have fun and right now that is reliving my teenage years. My wife much prefers that to some other type of mid-life crisis.

Anyway, I just got started and I'm excited for the challenge. I've not done an amp on this scale, but I've built a number of microphones and other small electrical devices and worked with soldering on lots of other musical equipment. I'm also blessed to have a friend here that I found out has built quite a lot of 100 and 50 watt plexi's. So, I have someone to look over my work periodically while I go through it to make sure it is functional and that I don't somehow kill myself (that would be bad).

Here are some pictures of the start of my build.

Also, any suggestions on getting a good Brown sound out of my 50 watt build from those out there would be greatly appreciated.

Happy Veteran's Day to my brothers in arms.

James

axeman · Post by **axeman** » Thu Nov 12, 2015 9:20 am

Excellent,welcome I think everyone is going to be looking over your shoulder here. Don't worry about asking questions, we will make sure you don't get electrocuted hahaha

jnew · Post by **jnew** » Thu Nov 12, 2015 6:22 pm

Yeah, welcome James. SOOOOOO the right place to get on your way with a nice build.

Oh, and 50 watters are killer.

Once you get it fired up, there will be lots of things to try, to dial it in for you.

mightymike · Post by **mightymike** » Fri Nov 13, 2015 9:55 am

You could just clone JNEW's 50 watt and you will be there first try.

jnew · Post by **jnew** » Fri Nov 13, 2015 11:03 am

Very nice compliment.

But I think we're learning that it is more about what's being done with the amp, more so than mods being done to the amp.

mightymike · Post by **mightymike** » Fri Nov 13, 2015 11:22 am

True... But this would be a good step in the right direction.

jnew · Post by **jnew** » Fri Nov 13, 2015 11:50 am

axeman · Post by **axeman** » Fri Nov 13, 2015 11:55 am

Mike are u at home now?

MUGuy · Post by **MUGuy** » Fri Nov 13, 2015 5:53 pm

Here goes with my first stupid question:

What type of potentiometers do you recommend?

I've used CTS and Bournes (500K and 250K) before on guitars, but I want to make sure I get the best type for this plexi amp. I see that Valvestorm has about 3 different brands.

Thoughts and recommendations?

mightymike · Post by **mightymike** » Fri Nov 13, 2015 6:37 pm

axeman wrote:Mike are u at home now?

Nope.. I did get the board though. Looks good man. I'm in Sturgis tonight enroute to Spokane, Wa.

That board is going to make a bad ass 50 watt.

mightymike · Post by **mightymike** » Fri Nov 13, 2015 6:55 pm

MUGuy wrote:Here goes with my first stupid question:

What type of potentiometers do you recommend?

I've used CTS and Bournes (500K and 250K) before on guitars, but I want to make sure I get the best type for this plexi amp. I see that Valvestorm has about 3 different brands.

Thoughts and recommendations?

I see Robert has the Alpha and CTS sets. Those are both great. I also like the MIL Spec sealed pots, but to be honest I really don't notice much difference in tone. They are just built like tanks.

Your question is not stupid.

Have you seen the build instructions for the kits? They are in PDF format and make the build process so much easier on your first build. There's a 100 watt and JTM 45 Instructions.

100 watt instructions
http://www.metroamp.com/downloads/100_W ... MP_KIT.pdf

JTM45 Instructions http://metroamp.com/downloads/JTM_45_KIT_V2.1.pdf

jnew · Post by **jnew** » Fri Nov 13, 2015 7:29 pm

+1 on the pots, I've used both. Flip a coin.

All controls are dimed and left that way, by my experience. Or if not dimed, just set and left alone for the most part anyway.

MUGuy · Post by **MUGuy** » Sat Jan 16, 2016 1:53 pm

Finally got some time off this weekend to put some more work into it (seemed less time than I anticipated over Christmas season). I am hoping to have about 2-3 on MLK Day and I was planning on getting through wiring the heaters and maybe up to step of installing the potentiometers (I ended up getting CTS pots).

However, I hit another snag that I need to fix before I start soldering. So, here goes another newbie question:

1. I purchased the ARS 50x50 filter caps from Valvestorm. However, the med cap brackets don't seem to tighten down on them very well. In fact, they are loose enough that I can wiggle them out without much trouble. Do I need to get a tighter bracket, or can someone carefully walk me through steps to get the filter caps installed correctly before I start to wire them up.

Any help would be greatly appreciated (including pictures or link to video if you know of any). Once I get the caps installed correctly, I'm on Step 6 in the Metro 50 watt plexi instruction manual.

Thanks,

James

jnew · Post by **jnew** » Sat Jan 16, 2016 2:35 pm

You want them snug and free from vibration and movement for sure. You could fabricate some rubber spacers on the inside of those clamps or just get ones that would fit proper.

Post by **ValveStorm** » Sat Jan 16, 2016 5:23 pm

For the ARS caps use one turn of rubber or a couple of turns of masking tape to make them hold in the clamps.
For the build to be successful, we need to know what PT you are using, and what OT you intend to use.

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