Metro JTM45

[dcburn]

I broke a barrel jack for cab input and obviously have to pull the chassis to repair.

I am still sitting on the Metro zero loss loop, I have seen forum members elsewhere say that installing the loop will affect/change the tone?
Maybe not for the better?

Regardless, still thinking about installing it since I am pulling the chassis anyways.

Just wanted to ask if there was any cool or good sounding mods while inside that anyone here has done/added?

Amp can get a little flubby, maybe a tight switch like in other amps?
Maybe smooth out the gain at higher volumes?

Anyways, just figured Id ask...

[lll]

I built the Metro JTM45 kit back in 2003; used my '96 JTM45RI as the base. The dumb fuckers sent me the wrong phenolic board three times before I got the right one.

I've never installed an FX loop in it; always used post poweramp FX with it.

Amp is flubby because that is the nature of the JTM45 circuit; very bass freq heavy. Need to turn the Bass either very low or all the way off.

Best mod would be changing values in the preamp to be more 50/100W plexi like. I eventually modded mine to a 68 50W plexi.

It sounded like this in 2016 (stock Metro JTM45 kit):


Modded it later that year to be more 50 watt plexi (and kept tube rectifier).

It sounded like this:


Modded it again in 2018 to be a '68 50W plexi with .68uF bypass on V2; replaced Mallorys with Sozo New Gens (and kept tube rectifier).

Now it sounds like this:

[dcburn]

Thanks for the reply, the clips sound great.
Reminds me of the red pedal PLX did.
Everything sounds so tight and crisp!
That sustain!

I’ve been toying with building the 50 watt but your clips make me just want to alter my 45. Quicker and cheaper.

Your clips make me realize how much right hand work I need.

Thanks again!

Can I just look at the differences in schematics between the two amps or was it just a cap change? One for one? Besides the .68uf

Of Just want to make sure I understand…

[dcburn]

One more question…

I see you and PLX using SoundCloud?
Can I just record thru my phone using that?
Would love to post sound clips, playing isn’t great but I always have tone questions…

I’ve used voice memos to send via text to friends, not sure though on using on a forum?

[lll]

'68 Plexi specs (EVH's to be mostly exact, except you'd swap out the 25K mid pot for a 50K linear)

Split cathode V1a 250uF/820 V1b .68/820
All coupling caps are 0.022uF
Bright channel coupling cap is 0.0022uF

470k mixer resistors
500pf mixer bypass cap
Bypass cap on V2a is .68uF
33k/560pF tone stack combo
100k NFB resistor at 4 ohm tap (that's for 100 watter - I'd recommend 47K/8 ohm tap for 50 Watter)
220k bias splitter resistors
0.1 uF cap on presence control
.022uf output couplers
.005uF bright cap on Vol 1 (optional)

50W OT that handles EL34s
A pair of EHX 6CA7s (new manufacture)

[lll]

One more question…

I see you and PLX using SoundCloud?
Can I just record thru my phone using that?
Would love to post sound clips, playing isn’t great but I always have tone questions…

I’ve used voice memos to send via text to friends, not sure though on using on a forum?

Not sure, but using phone is not good and doesn't represent the tone.

Need a computer audio interface and a DAW for, at the very least, decent results.
Then your amp needs to either be lined out (to audio interface), or miked cab.

SoundCloud and other audio website require .mp3, FLAC or .WAV files to upload

[dcburn]

Wow!
Best reply and thorough ever on a forum!

I admit to being pretty pathetic, I’ve earned both an AAS in Theory and another in Digital Recording using ProTools.
I’m not bragging, I just don’t have any sort of set up anymore. I still have an interface, but too old to use I imagine. Even still have my external hard drive from school with all my projects on it. Not sure how well I’d navigate ProTools at this point?

I totally get your point on the tone thru the phone, none of those voice memos sounded good, more for ideas…

Thanks again for the “ingredient” list.

Your three clips ripped.
That sustain and compression so tight and smooth.

My right hand needs help lol…