Another Metro JTM 45 joins the fold...

[emmjaydubya]

Picked up an unbuilt kit here in the classifieds and have been building it the last 6 weeks or so, what a blast! I did a TON of reading and I would like to thank everyone here on the forum for the vast amounts of knowledge and wisdom! It's my first build and I think it turned out great, thought you guys would like to see some amp porn, so here goes, the specs:

-Magnetic Components 1202-55 power trans for higher B+ (440 volts!) w/homemade alum tranny ring
-Metro output trans
-Mullard mustards and ABcc's in appropriate areas
-Brian H. board and fuse holder
-Larry grounding
-Hiwatt style output jacks
-Bulgin power jack
-front plexi panel from Sparky

The mods:
-220uf cathode cap
-.018 bright channel bypass cap
-470k mixer resistors
-.018 tone stack bass cap
-.022 PI coupling caps
-47k NFB on the 16 ohm tap
-32uf PI filtering
-5.6k grid stoppers
-flying resistor
-no bright cap on vol. pot

Here's the amp cradle, rotates 360 degrees and locks in 7 positions, really handy:



Had my friend/bandmate Mark weld the outside corners of the chassis for more strength:



Here it is before the board went in:



And as of yesterday!!

[emmjaydubya]

Fired it up with both volumes around 6 for a short time yesterday but I can't do it for too long at home. Not one problem, no hickups and quiet as can be! Crunchy and very much Marshall but still glassy and chimey. The amp I use in my band is a Matchless DC-30 which I love and I'm thinking these will compliment each other without being vastly different, we'll see. Going down to the rehearsal space today and begin the break-in process by giving it a real workout, can't wait! Gonna mess with other tubes a little later on, also. Here's a few shots in the headbox:







And with the early 70's cab I re-grilled (thanks to Jim @ Scumback):

[toner]

Beautiful work! Congrats. Marshall and Matchless, awesome!

[spaceace76]

impeccable work there! i like the mix of metro parts, CC resistors and mustards. looks like a sweet amp, hope you enjoy it.

[OnTheFritz]

Very nice!
I'm consistently floored here on the Metro forum by first time builders. Speaks volumes about this site and reference material, and of course the builder(s).
Great job!

[emmjaydubya]

Thanks for the compliments guys, and your right, the reference material on this forum is staggering, not to mention assistance from selfless experts like you. There is an answer to just about every question here if you look hard enough. Search function is your friend!

Unfortunately I've got an issue. Cranked it for about an hour and a half last night and it sounded great! Plugged into the bright channel, it's got tight lows and had a lot more gain than I thought it would. Got a little fizzy when dimed, but both volumes between 6 and 8 seems to be where it's happy (or where I'm happy!). Messed around with some of my pedals, everything sounded good till I hit my fuzz --- BIG MISTAKE!! Played two chords and the floor dropped out! I knew right away it was a power tube, looked behind and when I hit a chord, V4 was redplating like a roman candle!

Guess that's it for them, I will take some readings today to see where eveything is, I had biased them between 18 and 19 watts which came out to 41ma, I'll see if that drifted at all, but I think I see a pair of Gold Lions in my future and maybe a better rectifier. What do you think?

[greensblues]

I think the Gold Lions are vastly better sounding than the VA. I've sold and listened to many GEC KT66 and I'm not going to say these sound nearly as good or as complex....but they're the best new KT66 I've tried and a $80 compared to $500...it's a no brainer. I did splurge on preamps...Mullard across the board including a dual halo Mullard GZ34 and a 50's Long Plate in the V1 position. It sounds glorious. I have about 445 on the plates with my KT's biased to 40mA and it's just beautiful!!!

[emmjaydubya]

Sounds like those old tubes you have are the ticket! I got the Gold Lions but I haven't put them in yet. I changed the grid resistors from 470 ohms to a pair of 1k5 2 watt cc's, like the Udo Pipper JTM that sounds so good. Thought I'd give them a try before I gave up on the Chinese KT66s and sure enough, re-biased and they are working fine. Guess they just needed more protection from that mean ol' fuzz! Been flogging it at rehearsal a bunch as well as playing alone and it sounds FANTASTIC, with my LP or my Tele. I figure I'll get as much milage on the VAs during the break-in period as I can and then change em out. Also put in 3 Telefunken pre's, awesome, but I still have the cheapie rectifier.

Next up is building a JTM 45/100 and a 12,000 Superlead.