Lets Build a Small Box Marshall Plexi 50W Amplifier (by Modulus Amplification)

Подписаться 6 тыс.

Просмотров 18 тыс.

50% 1

Lets Build a Small Box Marshall Plexi 50W Amplifier by (Modulus Amplification)
* Please Like and Subscribe*
One thing I have always wanted to build is a classic Marshall head and for me the best amp was always the small Box Plexi.
This kit was from Modulus Amplification whom made the Champ And Tweed Deluxe Kits that I built in previous videos.
This is not a Full instruction video more just a diary of what I did and How I did it. Hopefully it may inspire budding amp builders.
UPDATE I did make one mod to this amp. When you bridge the 2 channels you get a squeal / oscillation. There is an approved mod that goes as follows
''Install a 7pf 1000V cap between plate and grid of V1A or V1B.
(solder this cap directly to the tube socket pins)
This is the factory method used to stop squealing.''
I could only get a 10pf cap. But it did the trick perfectly.
BUT READ THIS PLEASE!!!
Amplifiers have VERY high voltages in them if you are not proficent in electronics then do NOT attempt to build this.
Video of my Fender Champ 5F1 Build • I built a Fender Champ...
Video of my Fender Tweed Deluxe Build • I built a clone of a F...
Buy my music matthewnorth.bandcamp.com
Please follow me on the following Social media.
www.matthewnorthmusic.co.uk
/ matthewnorthmusic
/ mnorthmusic
/ matthewnorthmusic

Опубликовано:

12 ноя 2022

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 69

@mariannwatt2678 10 дней назад

Looks like fun nuild i have a 68 small box 50w plxi its bone stock ive had many marshalls but this one is my keeper iv had it 30 years regular tune ups no problems no breakdowns RIP jim marshall best amps

@MatthewNorthMusic 10 дней назад

I had a 1966 small box plexi sold it for £300 in 1999 had no idea of it's value but was broke at the time serial 2070 bet it's in some collection now! Paul Marshall told me in 2009 it was worth about 5 to 8 k !!!

@guitarmixing7493 13 дней назад

Congrats on great build. 10% tolerance doesn't change much

@scooterpinball Год назад

I just received my Ceriatone Plexi 50 Kit. I appreciate your video.

@MatthewNorthMusic Год назад

Good luck with it

@azlanx 6 месяцев назад

My guy this was really great, thanks for taking the time to make this vid

@sglee4708 Год назад

Damn you did a great job on that build and the commentary was a big plus thank you for the video I hope you make more

@MatthewNorthMusic Год назад

Thank you.

@TezHibmeister Год назад

Great video, that bob dylan album is great! Rock on!

@jquill6 3 месяца назад

Great vid, I was thinking of tacking the 50w bass amp based on the 1986 model from modular , this video is some tease 😮

@CFBPO 4 месяца назад

great video Matthew, would love to hear it with presence and all tone controls on 3, gain on 10, volume on whatever the neighbours will tolerate briefly! (Angus settings) and thru a Shaffer if you have one!

@itsonlyme9938 8 месяцев назад

I would that the cost of the kit is by far better value for the money and satisfaction of a homebrew Marshall is well worth the effort.

@stevelark9840 Год назад

Well done on the Build Matthew. Wiring looks great. I've been chasing down hum in Marshall's for ages, with some recent success. Check out "The Valve Wizard" grounding and ground schemes for some great info on how to quiet down your amp, if you even want to. A bit of hum is like the originals, but you can get them dead silent with a few changes to the ground scheme. Cheers.

@MatthewNorthMusic Год назад

The hum is very low and if you turn up everything to full the hum doesn't really increase its pretty much as it should be

@qua7771 10 месяцев назад

@@MatthewNorthMusic My Ceriatone is dead quiet cranked. There is a little 120hz (US) hum on start up when taken out of standby, (I'm assuming from the filter caps, and choke charging). After that it is amazingly quiet for a tube amp. I used coaxial cable for any internal leads carrying signal. I was careful not to have signal wires routed near power suppl leads. I oriented coupling caps with the the outer foil lead going to the lower impedance part of the circuit. I avoided using any components with ferrous metal in the signal path. I used star grounding. I also lined the head cab with copper tape, (which reduces hiss). Contrary to conventional wisdom, I did use NOS carbon comp resistors in the signal path that are alleged to be noisy. The CC resistors weren't an issue. I will say that some tubes/ valves are noisier than others. I realize you mentioned that you are satisfied with your current noise floor level, but I thought I would share some ideas for future reference in case you are interested. Cheers.

@RamonGoose 7 месяцев назад

great video!

@MatthewNorthMusic 7 месяцев назад

Thank you.

@MichaelSmith-rn1qw Год назад

Nice job on the build Matthew! I agree with you about using modern resistors as opposed to the carbon composite ones. Back in the day, they used them because that's what was available. Some people will say the type of resistor used affects the tone of the amp, but I'm not sure about that. When I have serviced my 50 year old Fender amps, at a minimum, I used modern resistors in the filter capacitor section, and in the bias supply. I'm surprised you didn't first power up the amp using a variac. Maybe you did and just didn't film that part.

@MatthewNorthMusic Год назад

I probably should have as I own one but powering up without valves in if there had been trouble it would have blown the trip! But you are right

@andyracksthecams Год назад

Using old type out of spec resistors does affect the tone. If you put the wrong value components in it isn,t going to be as desired. Those people who say it sounds different are correct. The bit they get wrong is it was wrong and they got used to it. Put the correct values in and it will sound as it was designed to sound. I know a hifi nerd who thinks he knows the score. He got told by some guitar amp repair guy that old capacitors sound better. What an idiot. 🤣🤣🤣🤣

@MatthewNorthMusic Год назад

Yes I've seen comments from amp nerds that think old capacitors are better. Idiots

@andyracksthecams Год назад

@@MatthewNorthMusic Great video btw. I'm just in the final stages of a Small Box Plexi build. I read that Modulus have some extra info which is useful but I can't get a reply from them. Grounding mods etc. I have some different coloured transformer wire but I'm sure I can work out what is what. I like your idea with the heater circuit. I think I'll try that if I suffer too much hum. Thanks for your help. 👍

@MatthewNorthMusic Год назад

@@andyracksthecams There are some more photos on there facebook page, i think thats where i saw the heater wires initally.

@heavymetalnewsdesk 2 месяца назад

within 10% tolerance is acceptable. Rarely will you measure a resistor and it be exactly what it is rated. very very rarely. Your measurements are all within 5% and less. to have ALL of your resistors exactly in spec would take all day long sifting and checking resistors. Build sounds great

@VintageDaedalus 3 месяца назад

Great and clean build, but crank it! :-) I know how loud they are when not using an attenuator - you actually NEED one! My JMP 50 build makes at 57W a clean wave - this is High Treble around 2. 🤣 Bone crushing loud. They need to be biased hot, because of the sag resulting. Thats the sound. By the way... did you check the direction of the capacitors? Looking by eye you oriented them wrong in certain positions, which will raise noise coming from the circuit. The outer foil of a capacitor needs to face to the lower capacitive side, because then it will act as a shield. Otherwise as an antenna. But to be honest, puristic as I am... I would have twisted the heater wires. 😇When staying 'in phase' and offering a good ground-layout there will be no hum. Marshalls original gournding is bullshit, take a look on "Larry Grounding". Cheers! David

@lousekoya1803 8 месяцев назад

What a great video ! Big thanks and new sub here from Quebec ! Did they supply detailed step by step instructions ?

@MatthewNorthMusic 8 месяцев назад

Nope just a layout diagram that you can download form the website.

@lousekoya1803 8 месяцев назад

@@MatthewNorthMusic Thank you Matthew !

@itsonlyme9938 8 месяцев назад

I think that the metal resistors would be a better choice @ 1% but not sure if they stand up high voltage I have been looking for a JMT45 chassis and found a a supplier in China made with alloy and only just found and discovered from another channel that Modulus makes them in steel which is much better I have free returns so I might send it back.

@aquilarossa5191 3 месяца назад

Looks to be much the the same spec as mine. But when mine is cranked, the presence squeals when turned up. I read on the Metroamp forum that is normal for early Plexi specs, but I dunno. They were saying it's because some DC finds its way to the presence pot. Maybe that's it. The other thing I want to solve is how when it is turned up there is very little margin between a soft note with a light touch and it going full bore blasting your face off. Just the slightest more pressure with the pick makes it go from an almost clean, soft note to full tilt. I know from experience that these amps are very sensitive like that, but this one seems more so. It does not do it so much plugging it into my Freyette Power Station, so I wonder if it's something going on between the output section and the 2x12 I use making that happen. P.S. I grew up in Milton Keynes, but have lived in NZ for yonks now. It is impossible to get many of the parts we need for this stuff, e.g., I had to import a 0.68uF cap FFS. No Jaffa Cakes here either, or vinegar at the chippy. Oh Well, at least we can watch the football live in the middle of the night these days (Saturday afternoon kickoff is usually around 4am Sunday morning here).

@NINEWALKING 15 дней назад

You want to twist your fillament wire. That cancels the AC field that those wires create, or you might introduce noise.

@MatthewNorthMusic 15 дней назад

You can also run them in parallel

@NINEWALKING 15 дней назад

@MatthewNorthMusic no dude parallel does not cancel each other. Trust me. If you do not visit Uncle Doug channel, he explains stuff very well. BTW I am amplifier designed and builder, so you can save yourself the time and benefit from the good tip. It was meant positive. BTW, learning from Uncle Doug is something I wish to everyone who wants to build a tube amplifier. He is a great teacher, and he has real knowledge, unlike the current influences.

@MatthewNorthMusic 15 дней назад

As I have linked elsewhere on this thread if you go to the modulus electronics website they actually recommend it. Specifically because as well as the wires being run in parallel they are also 90 degrees to the signal wires so they are well out of the way of causing any interference.

@NINEWALKING 15 дней назад

@MatthewNorthMusic your loss, mate. I can't make you help yourself or learn things. Going from up to down is something Fender used, and it's great. But at least read about twisted pair cables and AC signals and even data cables and shielding. The only time you do not need to twist your filament wire is when you use DC filament supply. Why every Marshall amp and Fender amp twisted cables? Why are computer network cables twisted? Be reasonable and learn. Or just stop claiming something you understood wrong.

@MatthewNorthMusic 15 дней назад

OK answer me this then why then are amplifiers made on printed circuit boards do the filament tracks run in parallel? And why is there no hum picked up on my amp here ? And hasn't been for over 2 years since I built it ?

@user-ws6sf4cl9o 7 месяцев назад

Super .. I bought a 20 Watt Plexi two Knob control only ...Volume + Tone, from Ampmaker UK a few years back . I really want to buy one of these ..especially these having more controls . Do they give you a schematic ..with the kit . By the way you did a cracking job on your build very tidy looks spot on !

@MatthewNorthMusic 7 месяцев назад

No schematic just a layout diagram so you need to have a good idea about what's going on.

@tzed2509 4 месяца назад

Thanks for this, hadn't heard of the brand of kit. I assume they can be wired for 110v US electricity? Also those glass things are called tubes, not 'valves' ;-) I'm kidding!

@MatthewNorthMusic 4 месяца назад

Yea you can get a 110v tap for the mains transformer

@tzed2509 4 месяца назад

thanks, I figured. @@MatthewNorthMusic

@univalve1 23 дня назад

those resistors are fine. do you think the original amps resistors were an better? hell marshall traded components around manytimes

@BenState 8 месяцев назад

The resistor value changes are totally normal.

@montygibbon1905 4 месяца назад

@MatthewNorthMusic 39:21 is there a technique to identify during the wiring-up phase which way 'round the transformer wires need to go? Or, is it flick the standby switch, and keep your fingers crossed? Cheers

@MatthewNorthMusic 4 месяца назад

Well I just followed the diagram but it's was wrong and yes there probably is

@GovmntLacky 2 месяца назад

Around the 40 minute mark… why did you swap out one of the output valves? The one behind the OT is considerably shorter than the other one.

@MatthewNorthMusic 2 месяца назад

Haha no I didn't swap anything out, i added a little gadget that splits out the cathode pin so I can measure the current with a multimeter.

@Ginajenns 2 месяца назад

Where did you get the Matthew logo made?

@MatthewNorthMusic 2 месяца назад

Someone on eBay

@serpentaking8697 Год назад

...some guitarplayer patch the channels to mix the channels. Is it possible to use this as a fx-loop?

@MatthewNorthMusic Год назад

Nope sorry

@ijs6962 Год назад

So when Marshall built these amps in the sixties, do you think they measured all the resistors so they were all the same value ? from the info I have, it's better for the values to be slightly high, for some reason they say the makes the amp sound better.

@MatthewNorthMusic Год назад

Probably not but at the time they were the best that they had tolorences back then we're way more loose the now was a rule of thumb resistors were around 5 to 10 % capacitors around 20%

@stevwills1445 Год назад

Eric Clapton has said in interviews that he shied away from marshall because they all sounded different from on another as opposed to fender where the sound was more consistent from one amp to another.

@Myrlin187 6 месяцев назад

That's funny as he was one of the most famous marshal men.Fender paid him a small fortune to swap.@@stevwills1445

@riders.oregon4474 4 месяца назад

What do you think of using this for a bass with a bass cabinet? I just w 0:06

@MatthewNorthMusic 4 месяца назад

Well these have always been used for both in the past reckon be great for bass guitar

@riders.oregon4474 4 месяца назад

Thanks I just went to Modulus and saw they offer a bass amp kit.

@scottwilcox6313 6 месяцев назад

Matt where did you get your name logo from or did you make it?

@MatthewNorthMusic 6 месяцев назад

eBay do a search

@tedrobinson3802 12 дней назад

At best you'll blow the place up. No pressure.

@TheTrondro 10 месяцев назад

I 've never seen heater cables done that way, normally they would be twisted and close to chassis ground :-) How is the hum ?

@MatthewNorthMusic 10 месяцев назад

This is the recommended way of doing it that modulus amplification suggested. Appears to be quite a good idea because there's no heater hum at all.

@geezberry8889 7 месяцев назад

who makes the iron?

@MatthewNorthMusic 7 месяцев назад

Antex

@KVKSHKFFSHORT Месяц назад

Please give us the scheme

@user-dn5ok5fz1t 3 месяца назад

Dude you need to twist the heater wires in a drill to lower the noise floor. Twisting them provides noise cancellation but you rather crazilly ran them side by side untwisted providing you zero noise cancellation. I dont know why you would do that ya dork.

@MatthewNorthMusic 2 месяца назад

I am not a Dork. Its a respected way of doing it and is recommended by the people that make the kit. facebook.com/media/set?vanity=100049629295448&set=a.725663852431251