NAD - 1968 50 Watt Plexi (clip)

[LLL]

:lol:

Well, not exactly...

Follow my amp build/mod thread here:
https://forum.seymourduncan.com/showthread.php?324666-Surgery-Time!-(JTM45-Modding-Content)

In essence, after a few iterations over a decade, I turned my '96 JTM45RI into a 1968 Plexi circuit (w/ tube rectifier).

Here's what it sounded like before:



Here's what it sounds like now (a quick clip in honor of the dude [BPJ] whose '66 JTM45 Bass first inspired me to get into building/modding Marshalls
way back in the early 2k's on the Plexi Palace forum):



Signal chain:

2008 Gibson Custom Shop '61 LP/SG Custom (57 Classics)
|
amp (everything dimed except bass "1", vol "9")
|
1x12 w/ Celestion Alnico Gold
|
SM57 hair off-center of cap
|
UA 2-610
|
DAW


- No EQ except hi and lo pass
- Waves iR1 w/ Sunset Studios echo chamber (just a touch)
- For wah, I had to use VST (BIAS FX) and manually move the virtual treadle with the mouse
- Izotope Ozone 7 on the 2

 

[Ayrton]

Re: NAD - 1968 50 Watt Plexi (clip)

Tasty!

 

[Lake Placid Blues]

Re: NAD - 1968 50 Watt Plexi (clip)

Are you using a SS rectifier?

 

[LLL]

Re: NAD - 1968 50 Watt Plexi (clip)

Tasty!

Thanks! :smokin:

 

[LLL]

Re: NAD - 1968 50 Watt Plexi (clip)

Are you using a SS rectifier?

No, tube. (NOS Philips ECG 5AR4)

 

[Gtrjunior]

Re: NAD - 1968 50 Watt Plexi (clip)

Wow! That sounds KILLER.
Nice work bro!!

 

[LLL]

Re: NAD - 1968 50 Watt Plexi (clip)

Wow! That sounds KILLER.
Nice work bro!!

Thanks! It does sound t!t$ whether shoving a SM57 in front, or slaving with line out and using iRs for speaker, or just slaving.

All that low end that it had before has been trimmed off. A lot less flab, a lot more muscle and bite.

 

[Gtrjunior]

Re: NAD - 1968 50 Watt Plexi (clip)

Thanks! It does sound t!t$ whether shoving a SM57 in front, or slaving with line out and using iRs for speaker, or just slaving.

All that low end that it had before has been trimmed off. A lot less flab, a lot more muscle and bite.

View attachment 85594

Yup, too much low end isn’t necessarily a good thing. It might sound great at home by yourself but in a band mix the bass guitar will win that battle every time.

 

[LLL]

Re: NAD - 1968 50 Watt Plexi (clip)

Status update:

It's been a half year since I did these mods and the tone still kicks mucho arse... no need or want to change anything else about it.

When I can stick an SM57 in front and record without using EQ ('cept hi/lo pass) and it sounds good, that's the litmus test for me.

The .68uF bypass on V2 is something else... gain gain gain for a plexi.

Apparently Marshall did this for a year or two and then stopped (why? who knows).

It's also a blast having split cathode now [ 820+330uf (normal) & 820+.68uf (bright) ] vs. the shared (typical '66 JTM45 circuit)...
...the way the amp was before, it had quite a lot of low end... and not tight, either. Of course the new Rk/Ck values and tone stack
help with that too.

I believe the Sozos ("new manufacture" that is) sound better than the Mallorys... in a "more clarity" way.

So, the only other Marshalls on my "gotta have one" list would be a 2203, 1959 and a 1958... next!

 

[Gtrjunior]

Re: NAD - 1968 50 Watt Plexi (clip)

Status update:

It's been a half year since I did these mods and the tone still kicks mucho arse... no need or want to change anything else about it.

When I can stick an SM57 in front and record without using EQ ('cept hi/lo pass) and it sounds good, that's the litmus test for me.

The .68uF bypass on V2 is something else... gain gain gain for a plexi.

Apparently Marshall did this for a year or two and then stopped (why? who knows).

It's also a blast having split cathode now [ 820+330uf (normal) & 820+.68uf (bright) ] vs. the shared (typical '66 JTM45 circuit)...
...the way the amp was before, it had quite a lot of low end... and not tight, either. Of course the new Rk/Ck values and tone stack
help with that too.

I believe the Sozos ("new manufacture" that is) sound better than the Mallorys... in a "more clarity" way.

So, the only other Marshalls on my "gotta have one" list would be a 2203, 1959 and a 1958... next!

I’d really like to try my hand at a Plexi build one of these days.

 

[SAguitar]

Re: NAD - 1968 50 Watt Plexi (clip)

That is just freaking awesome. Well done, mate.

 

[d1dsj]

Re: NAD - 1968 50 Watt Plexi (clip)

Nice demo, amp sounds fantastic.