Converting JTM50 to JTM45

[OnTheFritz]

The guy put this in his ad, saying the "builder" which I guess is you, said to him after building it.

"I employed a split cathode, the lead tone stack and mixer resistors, while retaining the .10 output coupling cap, which are Vintage Sozo's. They sound amazing in that position. I also used the Vintage Sozo's in most positions, with a couple standard Sozo's as well. AB carbon comps on the cathodes as well as the negative feedback resistor. (100k-8ohm tap) The PT delivers a tube rectified plate voltage of 465 vdc, and it really screams! The classic Marshall tones are all there, use the volume control on the guitar to clean things up, or let er' rip. I've installed the Lar/Mar PPIV Master Volume which works great. Really does give that cranked amp sound at reduced volumes. Of course it's at it's best when you get some air moving. Tube compliment is a pair of '59 GE 12AX7's from Tube Tramp in V1 and V2, and a Sino in V3. Output tubes are =C='s, and sound great. Tube rectifier is a Shuguang. The bias needs to be set accordingly. The SS rectifier bumps up the plate voltage to 480 vdc. Tightens things up quite a bit, the amp feels different, and absolutely roars. I like both, it's a mood thing! F&T filter caps, Magnetic Components transformers, and a Metro C1999 8H choke. Metro chassis and panels, and the head case is from Mojo via metro."

Sound about right?

Yep!! That's cherry picked from my email response to his recent questions.
This one was purchased by a guy in Montreal, who recently emailed me asking for info about the amp because he wanted to sell it. Has a red head box I bought from NYChief here on the forum.
I emailed him the ebay description because he didn't know what what going on under the hood. Was trying to help the Guy out.
Killer amp, and he got it from me for a *song*, because I had no reserve and paid out the ass for shipping.
Call him out and buy it!
Here's the entirety of what I mailed him:

"*Ebay listing:
Up for consideration is a 50 watt tube rectified Marshall clone. I employed a split cathode, the lead tone stack and mixer resistors, while retaining the .10 output coupling cap, which are Vintage Sozo's. They sound amazing in that position. I also used the Vintage Sozo's in most positions, with a couple standard Sozo's as well. See pics. AB carbon comps on the cathodes as well as the negative feedback resistor. (100k-8ohm tap) The PT delivers a tube rectified plate voltage of 465 vdc, and it really screams! The classic Marshall tones are all there, use the volume control on the guitar to clean things up, or let er' rip. I've installed the Lar/Mar PPIV Master Volume which works great. Really does give that cranked amp sound at reduced volumes. Of course it's at it's best when you get some air moving. Tube compliment is a pair of '59 GE 12AX7's from Tube Tramp in V1 and V2, and a Sino in V3. Output tubes are =C='s, and sound great. Tube rectifier is a Shuguang. I'll include a plug in solid state rectifier for an additional $15, just specify which spec you want shipped. The bias needs to be set accordingly. The SS rectifier bumps up the plate voltage to 480 vdc. Tightens things up quite a bit, the amp feels different, and absolutely roars. I like both, it's a mood thing! F&T filter caps, Magnetic Components transformers, and a Metro C1999 8H choke. Metro chassis and panels, and the head case is from Mojo via metro and NYChief from the forum. This amp totally rocks. Check out my feedback and bid with confidence. No Reserve!*"

[jasoncarmikle]

Alright, thanks. Kinda weird how this all unfolded, lol!

Is it really a nice sounding amp for my purposes? (shimmery clean tones, ACDC Crunch)

How much gain is on tap?

I have no way of playing it before I buy it, so I'm kind of buying on a whim here....and since he's selling it so quickly after purchasing it, maybe it's not "up to par" for lack of a better word.

What's a good price for it, in your opinion?

[neikeel]

The guy put this in his ad, saying the "builder" which I guess is you, said to him after building it.

"I employed a split cathode, the lead tone stack and mixer resistors, while retaining the .10 output coupling cap, which are Vintage Sozo's. They sound amazing in that position. I also used the Vintage Sozo's in most positions, with a couple standard Sozo's as well. AB carbon comps on the cathodes as well as the negative feedback resistor. (100k-8ohm tap) The PT delivers a tube rectified plate voltage of 465 vdc, and it really screams! The classic Marshall tones are all there, use the volume control on the guitar to clean things up, or let er' rip. I've installed the Lar/Mar PPIV Master Volume which works great. Really does give that cranked amp sound at reduced volumes. Of course it's at it's best when you get some air moving. Tube compliment is a pair of '59 GE 12AX7's from Tube Tramp in V1 and V2, and a Sino in V3. Output tubes are =C='s, and sound great. Tube rectifier is a Shuguang. The bias needs to be set accordingly. The SS rectifier bumps up the plate voltage to 480 vdc. Tightens things up quite a bit, the amp feels different, and absolutely roars. I like both, it's a mood thing! F&T filter caps, Magnetic Components transformers, and a Metro C1999 8H choke. Metro chassis and panels, and the head case is from Mojo via metro."

Sound about right?

Yep!! That's cherry picked from my email response to his recent questions.
This one was purchased by a guy in Montreal, who recently emailed me asking for info about the amp because he wanted to sell it. Has a red head box I bought from NYChief here on the forum.
I emailed him the ebay description because he didn't know what what going on under the hood. Was trying to help the Guy out.
Killer amp, and he got it from me for a *song*, because I had no reserve and paid out the ass for shipping.
Call him out and buy it!
Here's the entirety of what I mailed him:

"*Ebay listing:
Up for consideration is a 50 watt tube rectified Marshall clone. I employed a split cathode, the lead tone stack and mixer resistors, while retaining the .10 output coupling cap, which are Vintage Sozo's. They sound amazing in that position. I also used the Vintage Sozo's in most positions, with a couple standard Sozo's as well. See pics. AB carbon comps on the cathodes as well as the negative feedback resistor. (100k-8ohm tap) The PT delivers a tube rectified plate voltage of 465 vdc, and it really screams! The classic Marshall tones are all there, use the volume control on the guitar to clean things up, or let er' rip. I've installed the Lar/Mar PPIV Master Volume which works great. Really does give that cranked amp sound at reduced volumes. Of course it's at it's best when you get some air moving. Tube compliment is a pair of '59 GE 12AX7's from Tube Tramp in V1 and V2, and a Sino in V3. Output tubes are =C='s, and sound great. Tube rectifier is a Shuguang. I'll include a plug in solid state rectifier for an additional $15, just specify which spec you want shipped. The bias needs to be set accordingly. The SS rectifier bumps up the plate voltage to 480 vdc. Tightens things up quite a bit, the amp feels different, and absolutely roars. I like both, it's a mood thing! F&T filter caps, Magnetic Components transformers, and a Metro C1999 8H choke. Metro chassis and panels, and the head case is from Mojo via metro and NYChief from the forum. This amp totally rocks. Check out my feedback and bid with confidence. No Reserve!*"

Interesting the voltage you get as according to the blurb it is 690vac which should be maxm of 44ovdc, I guess it depends on what wall voltage and tap you use?

Looks like a nice clean build with good quality components. It is specced to a personal taste but could easily be modded to do what you want (if it does not do that already!).

[OnTheFritz]

Interesting the voltage you get as according to the blurb it is 690vac which should be maxm of 44ovdc, I guess it depends on what wall voltage and tap you use?

Looks like a nice clean build with good quality components. It is specced to a personal taste but could easily be modded to do what you want (if it does not do that already!).

I was rather *shocked* (rim-shot) at the higher plate voltage as well. I've used about 4 of these PT's now, and they're consistent.
Currently I have a '68 era project with a bridge rectifier like George's kit, and am getting 483 on the plates biased just under 70%.
Swapped in and out a couple OT's, and have the MC in there now, and it bloody screams and sounds amazing. But I digress!

Alright, thanks. Kinda weird how this all unfolded, lol!

Is it really a nice sounding amp for my purposes? (shimmery clean tones, ACDC Crunch)

How much gain is on tap?

I have no way of playing it before I buy it, so I'm kind of buying on a whim here....and since he's selling it so quickly after purchasing it, maybe it's not "up to par" for lack of a better word.

What's a good price for it, in your opinion?

There's quite a bit of gain on tap, definitely AC/DC and beyond. He's had the amp for nearly a year, but immediately emailed me after receiving it, saying he was unfamiliar with Marshall's, and wasn't sure this was what he was expecting. He's a Fender guy and a strat player, so I tried to help him out with settings, of course turning the amp up, and using the PPIV and the guitar volume control(s). Hadn't heard a word since, until he recently contact me about the info to sell.

The amp is definitely up to par, in fact it's got the *it* factor in spades. The harmonics and feedback just effortlessly bloom.
Based on what he paid, I wouldn't go over $800 shipped. It's worth every cent and then some.

[jasoncarmikle]

Ok, thanks.

He wants 950 shipped.....so I assume he's actually banking money from what he paid for it.....but if it's as nice sounding as you say...it's built cleanly and by hand, with great parts, and it's in great condition still.....maybe I need to bite the bullet on that one before someone else snags it up!

BTW, why did you end up selling it? Is it just a hobby to build the amps and sell them for ya?

Thanks again for all the info

[OnTheFritz]

Totally a hobby, I built it specifically to sell on Ebay. I had fun gathering all the components, tweaking, and the entire build process. A mix of Standard and Vintage Premium Sozo's was something I wanted to try, to get the best of both worlds.
Burning it in, and playing it for a week while the Ebay auction ran to make sure it was rock solid was a blast.
I did lose my ass on this, so my efforts didn't garner any payback other than my notes and experience.

You're welcome for the info, glad to help!
Barter for 900 shipped, and tell him you've spoken with the builder!

[jasoncarmikle]

I got him down to 900 shipped.

So how closely matched is this thing compared to a standard JTM45 tonally? I assume this hybrid amp has more gain/balls to it, is louder...and the JTM 45 has better cleans/edge of break up?

[jasoncarmikle]

Oh, and how many watts is this putting out?

I got a 2X12 cab with G12H (20 watt speakers) so I'm hoping this JTM won't blow them up.

[neikeel]

Oh, and how many watts is this putting out?

I got a 2X12 cab with G12H (20 watt speakers) so I'm hoping this JTM won't blow them up.

I do not think you have those speakers as they do not make them!
Have you actually got?:

a) G12H Heritages they are 30watts - they will be fine, or even G12H 30watt standards will be ok.
b) G12H25 (ie original rare early prerolas) these would struggle with a healthy 50watter
c) G12M25 (stock greenbacks) again might struggle with metal type constant rhythm work
d) G12M20 Heritages - be wary of slamming these unless you are a pure lead player
e)G12M20 (original prerolas) - don't do it!

One click on an attenuator or quarter turn on a PPIMV will keep most of the above safe.

[jasoncarmikle]

g12m heritage....got em mixed up. all i know is they sound great lol

[neikeel]

Yes they are good, and yes you should probably be careful diming even a healthy JTM45 through just 2 of those