18 watt update

[NewOldCokeDave]

18 watt update (new 8/17 info)

I have ordered the transformers, chassis, faceplates, fiberboards and the Marshall face parts. (Roughly $2200 so far)

There is one little snafu. I cannot locate the Marshall indicator lamps.(I have called Hoffman, Mojo, Ruby, Sprung, Angela )
No luck and no idea when they will come in. I am sourcing an alternative for this part. Similar but not exact.

Also I had sourced a turret lug board, but as it turned out it was 8 turrets short of being useable, so I had to make a call. Do I retool to accommodate the turret lug design or do I go with G10 eyelet boards? I have selected to go with the G10 eyelet style board, while not the most historically accurate, it is functionally identical. G10 eyelet boards are the flat style boards that are in all point to point Fender amps and I think later Marshalls.

I plan on making more orders this and next week, so please make sure that you have submitted your check to me so I can cover the costs.

I hopefully anticipate that shipping will begin on or about 4 weeks from now. ( I may be able to get the option 1 stuff out a bit earlier as I plan on making the fiberboards up in the next week and all we'd be waiting on would be the transformers.

Most of the suppliers I use have pretty quick turn-around, so the parts will be coming in shortly after I finish ordering. (week after next)

OK the documentation part. I plan on, at the very least, including a layout diagram of the amp's internals and the schematic. I would like to include an instruction manual of some sort, but I think my time will be limited in order to get this out. Rest assured tho, between this Forum and the 18 watt forum we will be able to supply enough information to have everyone be able to build their amps.

The layout alone pretty much says it all and if you follow that you've got 85% of it. The other 15% I'm sure we'll be covering in one form or another

More news as it develops.

-NOCD

 

[Ed Rafalko]

NOCD-
Is the address where I need to send the check posted anywhere?

 

[NewOldCokeDave]

Yep in the thread "18watt kick-off"...

Here it is again:

Dave Johansen
c/o Barclays Global Investors
10815 Gold Center Dr.
Rancho Cordova, CA 95670

 

[RICH]

I noticed in one of the pictures that it looked like a terminal block was mounted next to the output tranny, I'm hoping that this is the taps for the ohms. I want to run a 16 ohm cab with this, I'm assuming that the different taps are there, or is this just a straight 8 ohm head? Not that it matters too much, by the time I build the combo cab I'll have the right speakers, but 16 ohms would be nice.


Radio shack sells these real close looking indicators that look like the ones that come on the early 70's steel face 50s and 100s. It has a neon bulb in it, so I usually pluck out the neon and bulb, and replace it with the regular 6 volt bulb that they also sell. From 2 ft away you can't tell the difference, I use them alot.

 

[Graydon]

Output trannys

Hi guys,

The output tranny has three taps at 4 8 and 16 ohms.

Also, Mouser sells a round indicator lamp with a chrome bezel that looks pretty close the the older style indicator that we sometimes see on plexi heads. I've seen a round indicator on a real 18watt too, so I wouldn't hesitate to use that one. The only problem is that you need to open up the hole in the plexi panel and the chassis a little for that indicator but that's no big deal if you work carefully.

I guess I got one of the last small square indicators from Hoffman.

 

[NewOldCokeDave]

Yeah you dog!! Hoffman told me he's out and doesn't know when he's gonna get more..

RICH, I'm thinking of getting some angled aluminum stock and mounting the three switchcraft jacks (which I'm including)
on a piece of 1x1 aluminum L angle.. My original idea was that we'd drill up from inside the chassis to the top and mount the three jacks that way. Or have a terminal strip and "change" it by soldering one jack lead to one of the three taps...

Either way would be cool..

I don't have a lot of time left to do machining, so I'll try and include whatever parts we want to call standard.. Hey RICH ya got a mill you can mill out some angle brackets???

I could send you some jacks pronto so we could get a jump on it if you feel like taking the time to do this..

-NOCD

 

[RICH]

Yup, I have a milling machine, what exactly do I need to mill?

 

[NewOldCokeDave]

Probably more drilling than milling, but what about this:

A piece of aluminum angle like the picture shows that you were talking about, but instead of just one hole how's about long enough for three holes, one for each jack of the output 4-8-16 and on the other side drill two other holes for mounting onto the chassis, something big enough for a 6-32 screw. So I figure these mounting brackets would be roughly about 4" long..

One other quick question, do you have easy access to angle aluminum like I'm yakkin' about here , and do you want me to provide it and mail it to you with a Marshall jack..

I'd do it on my drill press, but I don't have a small milling table to get the holes straight and in line.

Let me know if it isn't too time consuming for you and if you can do it. I'll reimburse you for the materials, time, etc.. Give me an estimate pls... (That is if you have the time to do it of course!!)

Thanks!!

-NOCD

 

[RICH]

Hmmm, I don't know if I have access to that kind of aluminum angle stock. I'm also wondering if a marshall jack will make it through that thick type material, but the input jacks are shimmed with washers in the super lead heads, so its possible it might work. I have a few marshall jacks here, so you wouldn't need to send me any for size purposes. I'm wondering if the piece should be threaded for the mount screws, or if its better to just drill mount holes and use a nut with the mounting screws. THEN, I'm thinking about whats wrong with just drilling the 3 holes in the chassis? I figure that would be stronger than a piece of angle aluminum only because when you push the plug into the jack mounted in an angle bracket, it may flex the chassis and eventually loosen up the bracket, or deform the chassis. Whatever you want to do, I'll drill the things and stamp a 4,8, and 16 under each hole if you want to use the angle bracket, that would look cool with a stamped number. If you can score the aluminum, I'll do it, screw the labor.

 

[NewOldCokeDave]

Let me see what I can come up with re: stock.. Ya know, I'm including Switchcraft jacks not Marshall for those as they have a longer thread.. about 1/2". I think drilling would be fine.. and stamping would be EXTREMELY cool.. Let me check my metal suppliers and see what they've got.. Good old Lowe's may even have what I'm looking for.. I'll get it mailed out to you as soon as I get it!!

I don't think that drilling the chassis would be all that bad, but I just thought it may be a bit cooler to have the bracket... I dunno..

Thanks!!

-NOCD

 

[Graydon]

Hi guys,

The Marshall jacks are designed for exactly a 1/8" panel thickness. With
the fibre washer that is supplied, they just snug up perfectly. If you use
a panel thicker than that, they may not catch any threads. With a thinner
panel, they may not tighten up. I'd recommend you use the Marshall jacks at
least on the front panel with the plexi as that is exactly 1/8" thick,
total. (ie, the chassis is 1/16" and the plexi is 1/16" which equals 1/8"
total)

It would be cleaner to put the output jack and an impedance switch in the
chassis, but I wanted the chassis to look more authentic than that so that's
the only reason I made that angle bracket

BTW, 1/8" aluminum angle should be readily avilable at any decent metal
supplier, or possibly at Home Depot/Lowes.

 

[NewOldCokeDave]

Oh no.. All Marshall where it shows.. (On the front panel.. )
I'm using the switchcrafts for the output only.. back up underneath the chassis.. I found those indicators you were talking about.. I'm ordering them this afternoon.. 'bout the same price as the Marshall ones!!



-NOCD


Hey we're rolling gang... I have a surprise for you. I've been able to source mostly NOS Allen Bradley resistors for the project!!


-D

 

[EdA]

Ive just ordered mine from Dave! Anybody (Graydon maybe) know the exact dimensions of the original 18w 2x12 that Marshall offered? Was it the same size as the 45w Bluesbreaker or smaller? -Ed A

 

[NBlair930]

EdA -Did you recently win Lotto?

EdA,
You the man! If I've been keeping up to date on these posts, you pulled the trigger on BOTH the Blockhead JTM45 & the NOCD LP Forum 18Watt Cone. I'm green with envy. The 18Watt 2x12 soumds like a great idea. :dude

 

[EdA]

Yeah shit, I havent played Marshall in years, now Im getting two at once! (well clones anyway). But this is what Ive always wanted, the simple handwired, better trannied old type. I still havent heard them yet, so the jury's out and Ill have to sell my Matchless to pay for them but if I like 'em, bye bye Matchless.
-Ed A

 

[NBlair930]

EdA,
I'm too am toying with the idea of getting one of the Blockheads, but the Bruno Undeground 30 will surely have to go. I've never heard one of these 18W in person (only MP3's) so I'm real curious: being Class A el-84's, is it all Marshall? Voxy?
Thanks for the referral to Ritchie @ Murphy's. He did some minor repairs on an amp -honest, knowledgable, reasonable $.

 

[60burst]

100% marshall. No Voxy vibe at all. By just hearing the amp you would never guess there are EL84s in it. The 18 watt is as Marshall as it gets.........:60burst

 

[NewOldCokeDave]

Friday 8/17 *UPDATE*

I just wanted to clear a few things up..

1) I don't think that the 18w is Class A, it is cathode biased, but I'd have to check the operating range of the el84s in circuit to verify where it is running in the range of A, AB, B. There a LOT of controversy regarding this and I'm not going to go there, but from what I can see so far it all points to AB cath-bias. True class A is single-ended like a Fender Champ, or such. You can have multiple Output tubes in Class A, but they are usually in parallel with each other and are single ended. I *have* seen in RCA documentation of something called Class A push-pull which runs in the Class A range, but is put together in a push-pull fashion like 95% of all the amps out there which run in AB. Class A P-P is possibly the MOST argued definition out there. I'm not going to venture there in this thread..

2) I already emailed EdA on this; But the cabinet dimensions (at least in '66) were for the 2x12: 28wx20hx9d, for the 1x12 and 2x10: 24wx20hx9d

3) All the kits have been sold... I have accumulated a large amount of parts and a lot of parts are expected next week, so with any luck the week folowing I can start shipping the Option #1s and in the following week or two I can follow up with the kits.
I will be building the completed ones during all of this after I have recieved the bulk of the parts, so hopefully those will go out the week after the Option #2 kits.. Then I'm going to Disneyland..


I'm planning on posting a weekly (or more frequent) update as we progress, and I'd like to keep all questions on the Forum or on the 18watt forum so all can benefit from the information shared.

BTW, the amps output impedances will be 3-7-15 ohms, just like the originals..

RICH!! I got a hold of some impedence switches so we don't need to do the angle brackets.. Thanks, tho!!


-NOCD

T

 

[Ed Rafalko]

youdaman, NOCD.

 

[RICH]

See that, just because I cleaned off the mill we got switches. COOL!!!! I sent the money order, let me know when you get it.