Holiday Vintage Marshall Builds...

[pleximaster]

This might be the wrong section to post in but it is vintage Marshall related.

I about vintage Marshall sound and the builds have Original Marshall vintage knobs on them and they are compleately build up by vintage parts.

I have finally started to build some designs of my own in the search for the tone at lower volumes and in more compact format. I have started out doing three different amps with different preamps and power amps. Of cause I have been inspired by the original Marshall designs and I have took many ideas from various posts on forums on the net. I do this for the fun only for my personal mental satisfaction

I just happped to have three old avantic beam hifi chassis that I got in an estate sale some years ago together with a lot of slathered Marshall amps. (Actually one chassis I bought on eBay since I was missing a knob for one of my really one jtms and they are the same on the spa, good to know! Copper ring knobs, I have four extra know!!!)

The mini beasts I am building are

1. jtm45 inspired with rectifier and el84 push pull (real choke) normal and bright Chanel that can be switched on in parallel, master volume, fixed bias, Erie resistors mustard green 50s caps
2. Late 60 plexi, ss rectifier, one Chanel, 6v6 single ended power section, master, NFB cathode bias, choke, mustard caps
3. Hotrodded marshall/trainwreck wannabe with two push pull el84, choke, ss one channel, tube rectifier, mustard, phier resistors

AND a big thanks to Danfrank for all help with questions on transformers!!! Dan the transformer man!

Plexi

 

[liontato]

Awesome! Let’s hear some clips if you get time. Lower power is where everything is heading.

 

[pleximaster]

Thanks!

Here is a first clip of the JSM-5 (number 2 in the description above.

 

[danfrank]

Nice!!! It's so much fun to build stuff and see how it turns out.

One thing to note: With a single ended tube output stage, B+ voltage NEEDS to be lower than with a push-pull output stage so the single power tube doesn't go into cutoff (turn off) and cause bad sounding distortion. Take a look at the data sheets for these tubes to get a general idea where the B+ voltage should be for single ended "class A" operation...

https://frank.pocnet.net/

 

[BowerR64]

Why did you decide to mount everything inside the chassis that way?

Rather then putting everything under and the transformers and tubes up top like the classic designs?

That way is similar to the current SS amps the way they put everything inside

That clip sounded really good, i like its not over the top gobs of gain

 

[pleximaster]

Why did you decide to mount everything inside the chassis that way?

Rather then putting everything under and the transformers and tubes up top like the classic designs?

That way is similar to the current SS amps the way they put everything inside

That clip sounded really good, i like its not over the top gobs of gain

Many reasons!

1. Firstly I had them... use them or throw them away... and three of them makes a cool set.
2. They are made in 50´s masterminded designed and engineered, they stuffed so much in them still retained airflow and serviceability. When working on these chassis you can balance them on any side.
3. I wanted them to be compact and light weight. I already have over 150 Marshalls and they take up a lot of space. these are only about 14 inches wide and 4 inches tall. I one wants to you can easily attach side braces to the metal chassis and mount them in a rack system for gigs or in a studio.
5. It was also a really cool challenge to have the chassis limitations and design boards features and functionally of these amps. I am still not down with the layout of the third one. Compromises of features should not be a considered a bad thing but actually a driving force for the innovative and a push towards the right decisions of priority.

The reason I do these builds have also many aspekts but its not for money (someone ask if I sell these) No, the parts are probably worth more before I smack everything together with into an amp.

(And here are some personal thoughts... )
I do this because my "personality profile" needs to be occupied with projects and as soon as a project is done I take on some more. Good or bad this is who I am. However I have had good share of both physical and mental health, my heart have stopped a few times and my aorta and iliac arteries burst leading to massiv internal organ disrupters... I been dead a few times! I can put that on my CV. So I need some more from my projects to keep mind at ease, since projects have an end. So using these projects for learning new things every day, meet new people, challenge my self in things I have not done before (it doesn't need to be more extrem than going from building a push pull amp to make a single ended amp... hahaha!) That makes me feel good, you can never be fully educated and there are always new people to interact with that has new perspectives other values and different experiences than I have. And embracing that, I think... I think that is life...

Everyone has a different view on a problem, therefore differences in what is wrong or right varies, there are always more than one solution to it, there are always new things to learn. By collecting as much knowledge from other people you can make you own opinion stronger as one have more to support it. And ones results will improve.

AND ALSO there are more than one Marshall sound!!!

plexi

 

[pleximaster]

The last in the trio...

The layout is coming around...

Two el84, gz34 three ecc83,

 

[ampmadscientist]

I love to tweak old amps into guitar heads, quite fun.

 

[john l]

Those are absolutely gorgeous!

 

[ampmadscientist]

Those are absolutely gorgeous!

I like to paint the cabinet purple.

 

[johan.b]

If you draw a black line from knob to knob, it'll be a smiley. ..
J

 

[pleximaster]

I like to paint the cabinet purple.

Actually my first plan was to make one red but I went with the traditional black and gold look.

If you draw a black line from knob to knob, it'll be a smiley. ..
J

Yes, it is supposed to make you smile!!!



Here are update on number three...

 

[pleximaster]

I work with them I parallel. No 3 is getting (gold plexi panal) crowded. I had to move the speaker output jack as it interfered with the el84s. (Not that the transformers arenot mounted and connected the OT and the MT are not the ones to be used as dummies and only there to check space inside.)

I am also working on a gain boost that will be switchable option in front.

No 2 (black plexi panel with gold string) is the one in the YouTube clip and will get switchable bias fixed and cathode.

No 1 (black panel plexi) had a shortened filter cap (I used AB old reformed one) but it failed catastrophically and brought down a very nice old RS output transformer. Well shit happens... but I am installing modern caps now and fail resistors....

Plexi

 

[BowerR64]

When i was 20 i severed my aorta in a car accident, almost bled to death and it is what caused my paralysis. I know what you mean about projects

150 Marshalls is madness, got any pictures of that?

 

[pleximaster]

When i was 20 i severed my aorta in a car accident, almost bled to death and it is what caused my paralysis. I know what you mean about projects

150 Marshalls is madness, got any pictures of that?

I don’t have them in the same place... takes up too much space for some reason.

I have posted many pics here over the years but photobucket have messed things up... I am sure to post new ones when I find the time.

I feel strongly for you. Artery ruptures are severe stuff as you know!

When the my aneurysm broke 1,5 year ago I felt a strong pain in my chests then I don’t remember any thing until they woke my up from intensive care... I then thought I was dead and could really recognised my own family. All my blood had also been pumped out inside of me, bleeding to death inside sort to speak. This caused all internal organs to fail. I guess when I woke up I was on every drug in the pharmacy!

I got blood hemorage around the spine and they didn’t dare to remove it as I could get paralysis. Most blood have been absorb now but some have been encapsulated and turned into something scare tissue like making me less flexible and induces strange back pain.

But let’s continue to talk about amps more fun then health issues!

The compactness of these amps are a specific goal for me as it saves space! I can have four of these taking up only as much space as one small box Marshall. Marshall’s and other especially British 60-70 made amp heads are soooooo oversized!

Plexi

 

[BowerR64]

Have i seen any of the amps on that Johans youtube? that guy has had his hands on a many number of Marshalls

You guys are lucky to have played threw so many different Marshalls pretty cool stuff.

 

[danfrank]

Hi Plexi,
Great engineering job on these amps. They are very compact! One thing to be careful of is overheating because of the tight fit and possible restricted air flow. Make sure there is good ventilation in the amp when they are closed up.
Excellent job!

 

[pleximaster]

Thanks Dan!

I have thought a lot about ventilation and the casing is metal mesh and there are vent holes in the bottom as well

I have even made room for a modern laptop fan if needed!

I got a set back to day as I was wiring up one of the mts

The ct and one of the ht wiring had broken off inside the winding paper.

Sometimes I wonder why I bother using vintage parts and not by a new one and hook it up. But where is the “glory” in that!!!

It took som time carefully finding the wires fin the side and reinstall them to the taps!

Working perfectly again!!!

 

[pleximaster]

Have i seen any of the amps on that Johans youtube? that guy has had his hands on a many number of Marshalls

You guys are lucky to have played threw so many different Marshalls pretty cool stuff.

Johan have made demos of many of my amps!

Best pkexi

 

[pleximaster]

More holiday updates!!!

The JSM-5 got a bias switch (cathode/fixed) thanks (Dan your switch layout was perfect) and some extra stuff I like to discribe as jtm/jmp modes.

Here are the amps in their vented cases

Plexi