Marshall 1987X clone project

[Spunky]

VOX,

I can buy the US version of the Tranny or the universal. No need for the selector is USA voltage only.
I am thinking about a universal model and using a recessed selector switch.
I have no idea what OT comes in the Weber kit.

I don't need to make it dead stock origional....
I just want it so have the monster Plexi sound.

 

[Voxman]

Next anal issue ;D ... are we to have a split or shared cathode? And/perhaps a .005 bypass cap on the volume wiper? Inquiring minds want to know! I'm curious as I've just built 2-36 watt and one 18 watt marshall which were hybrids of the AC30, Marshall 18 watt and JTM 45 topologies. So far I've used heyboer and Greydon trannies .... and each one evolved as I built them based on the idyiosancties of the builds .... quite an addactive sickness this build thing :uglystupid2:

 

[Spunky]

I love anal...just keep the cat thermometer away from me...LOL :bs:

I found where the bias trimmer pot is in the layout so I'm happy there.... :)

split or shared cathode.....???????? I don't know the difference but I want the monster Plexi sound of the origionals....what are they, split or shared?

How are the Heyboer trannys?
I'm probably going to use the OEI or the Heyboar and haven't made up my mind yet.
Do you think the Mercury Magnetics are worth the price? Are they better than a Heyboer?
Is there another reasonably priced tranny out there?

I need to make the purchases now as this may be my last build for a while. After the bride comes here, I will be limited in my spending and my allowance will be miniscule.
A monster 50 Watt Plexi is the goal here.....

 

[Voxman]

Don't know what's best yet as I've done 2 -36watters, one with heyboer but w/some changes then i loaded'd greydons into an 18 watter while building 2 at once,another 36 w heyboars. next week I 'll start on a 36 with heyboarsbut ya tune them up great withclose by perhaps different values of resistors and caps.. mixing types in different applications for that killer sound all ay own!
Can't wait to build an AC30/4 and /36 topbooster too .... Enjoy!

 

[Spunky]

VOX,

I'll see if I get a response to the OEI email I sent on the tranny.
I love doing business with smaller companies that produce small quantities of hand made nirvana.
If that doesn't pan out, I'll go the Heyboer route.
I realized I ordered the lower headroom ballsy tranny with the Weber kit and I wanted it 110-220-240 but I selected 110 volt only.
I just sent Ted an email to straighten that out as I only ordered the kit on Saturday.

great withclose by perhaps different values of resistors and caps.. mixing types in different applications for that killer sound all ay own!

I don't have a clue how to do this but it will be fun to learn. :uglystupid2:

I looked for the pictures of the big box JTM45 I took to look at the boards but couldn't find them...Back to the archives :BangHead:

 

[Spunky]

VOX,

I dropped the hammer on a Drake 50 watt JMP tranny......

What do ya think?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7415430816

 

[Spunky]

OK
here is my BOM so far.....

Weber 6M45P 50 watt plexi kit complete
Sozo mustard cap set
PEC pots (5)
Metro Master Volume Kit
Allen Bradley NOS Carbon Comp Resistors
Blank board material for circuit board
Metro Keystone turret lugs
Heyboer Plexi Power Transformer 1202-118
Drake 1967 Plexi Output Transformer 784-139
Marshall 5 pin logo for Plexi
Mercury Magnetics 3H Choke R103

cost is at 816.20 delivered..... :o

 

[Voxman]

Here's one just like you seem to be planing and with the same Drake replacement tranny! Small world you went with the later choke and what seems like the later output so I think it's could sound a bit like a 71'/72' small box which were hot and very much got in ya face around 2 or 3! A very desirable amp to have ... I'll post pics of the same 70' Parks... one w/ split and one with shared cathodes! he split tended to be more chimney and brighter while the shared tended to be thicker in the midrange with a darker timber to the treble content. Both are very exciting to play as I'm sure your's will be too!

http://cgi.ebay.com/ws/eBayISAPI.dl...61&ssPageName=MERCOSI_VI_ROSI_PR4_PCN_BIX

 

[Spunky]

WOW.

#1500.00 and reserve not met!

I changed the choke to the MM MC10H Tone Clone as the one origionally speck'd was for a 100 watt Plexi.

Should be a bad ass mutha'

I leaning towards using the FREDs in it... :)

 

[Voxman]

That's what I suspected about the choke but :dontknow:

Put the freds in so ya can remove them neatly if desired as ..... ya never know for sure till ya know! ;D

 

[Spunky]

Ha Ha Ha.... ;D@VOX.....

That's what I suspected about the choke but

I'm hoping you will keep me straight here. I am doing this all on my own and hoping for the best. and I'm an idiot!
I'll start with the cheap diodes for the power, then I'll build a "FRED board" to swap into it to test the sound after the amp has had a chance to break in.
I won't be able to tell shirt until it's biased, tuned and broken in properly.

This Drake OT was used in late 1967 Plexi's according to my database.
http://marstran.com/Historic Data Base.htm

My goal is a 1967 Plexi with huge balls.... :dj:

Call it "Extra Testicle" O0

 

[Voxman]

But I thought that one you won was a new one , not an oldie? As a new Drake probably has M6 laminates! And the whole ballgame is the output iron which had many inefficients which contributed to the plexi sounds! I always loose my mind when choosing transformers :uglystupid2: :-X

 

[Spunky]

VOX,

Yes, it's a new one. The guy says it's like the early seventies metal faced.
So I will have a 70's "Extra Testicle"....cool beans O0

I've seen the 74' big box JMP50 and it has a circuit board with traces.....YIKES :o

Where is a source for more of the Drake OT's. I can't find them anywhere....

OEI never responded after 2 emails.......

 

[Voxman]

Don't have a source but I've never have persued any ... yet! ... but I looked downstairs and I only have 2- 70's sets left! UHOH! :cry: