My Marshall 10 watt to 18 watt conversion project.

[Scott_1930_Popular_10Watt]

Hello all,
This is my first post as I am a new member. I have a rare model 1930 10 watt Popular amp with twin 10" celestions and I want to build a new head to screw into my 1969 cab. I love the basketweave cloth on the grille. I will take the stock speakers out with the 10 watt head and keep them all original. So my project is building the new 18 watt head, footswitch, speakers. I am requesting the best kit and or materials to buy to build my 18 watt head. The 10 watt head uses two ECL 86 power tubes and one 12AX7. It is great for a bedroom amp. The new 18 watt head would be great for small gigs. The build number on the chassis tag is "M125" for anyone who wants to know.
Thanks for all info, Scott

[zaphod_phil]

I'm finding it a little difficult to follow what you're exactly trying to do here. You're saying you want to build a new 18W amp into an old cab to make a combo? That's not a head amp, if you do that of course. And how does the 10-watter come into it?? That amp as you probably know is worth a fortyune, and you don't want to mess with it in any way. So can you please try and spell it out again?

Generally, some of the the best 18W kits are Graydon Stuckey's of GDS Amplification (respect!). FYI, I'm also currently building a 13W version of the 18W Lite II which uses two ECL86s and a 12AX7. In a well-designed circuit you can get a lot more power and tone out of ECL86s than the stock 1930 does.

[GlennG]

Hello Scott

Welcome to the forum, you have found the right place to be. Fortunatly you can build an 18 watt head and the grill cloth that is on your 10 Watt is available so you can make it all match the 10 Watt. With the price of vintage gear going up every year, it would be a good idea to keep that 10 Watt original because it is only going to keep going up in value as long as it is in its original condition.

Graydon Stuckey sells a first class kit with top shelf parts including Heyboer Transformers and gold plated tube sockets, etc. He has a website if you would like to browse

He has completed amps, kits and parts for this amp, and he`s a nice guy to too.

http://elektro.cmhnet.org/~graydon/18wattmain.html

Glenn Gertis

[Scott_1930_Popular_10Watt]

Thanks Guys,
I am going to keep my amp stock the 10 watt and it sounds sweet as it is, but I want to build a 18 watt and change it into my 69 cab. It sounds much more powerful than 10 watts as I have strong new NOS tubes in it. It's only 4 screws on the chassis and then to remove the speakers. IM not going to remove the solder joint from the output tranny to the speakers, so I will take it out and place in a custom box and store under a bed. The 18 watt chassis I should call it, I call it a "head" with my girl all the time to simplify the lingo here at home. It will not hurt anything removing it this way. I want to build the chassis myself, I looked at the 18 watt kits here on the site, they look great. I would like to learn the tricks to make the best I chassis I can. If you have ever seen a 10 watt it has the three 'knockout' plugs that you can remove 2 bolts and install a 12AX7 as they did install one when they built the amp. So I believe the 10 watt chasis is the same as the 18 watt chassis. It looks so simple and the tone it produces is incredible. I have many amps, but this one is so special. I play it everyday and now I have the fever for more. I may build another cab to house the 18 watt head, but for now I will just put it in the 10 watt cab. The plexi faceplate is what I have not seen yet in the kit, any link to it? I don't know what the 10 watt amp is worth, but I will never sell it. When they built the amp in 1969 the paper build tag says "M125" on it as a model number. I will post photos of it when I can find out where and how to do it. Then again, I may just build a new cabinet for the 18 watt, either way IM going to build one. The 10 watt amp has the white powercord on it, the original one I believe. It had a lug soldered to the ground connection then it was bolted to the 50/50 cap bolt. The problm was it was not clean and the connection was a bad ground. I have a great tool from www.groitsgarage.com , it's like a wire brush 1/4" round in a mechicanial pen type tool (made in Germany, they have refills for the tool too). I use it to clean small metal before soldering etc. So I cleaned the ground, lug fitting, brass bolt threads and removed the small washer it had on it and bolted the clean parts back together and WoW, a whole new amp. Before the amp sounded like it had scratchie pots when you hit the strings on the guitar, but when you had the volume up and did not hit the strings, it was quiet. It only made the scratchie krackle when the strings or sound was made. I thought it was a bad cap, turned out to be the ground. So if your amp(s) do not have the ground soldered to the chassis be sure to check this connection. I put a Telefunken 12AX7 in my preamp and two RCA ECL86 in and it has great tone. Not great, unreal tone. You know that "magical" sound that only comes out of a very few amps. I have been looking for a 18 watt amp for many years, the crazy price has let a few slip by. Now building one seems to be my best bet. It's too bad Marshall did not make many of the low watt combos for the market like Fender did. IM sure I will have many post on this site during my project. It's nice to have photos of the original 18 watt amps on this site to use as a guide for the build, wire colors etc. that was a nice cup of coffee. scott

[Graydon]

Scott,

I have the plexi panels too. The plexi panel is included as part of my chassis. If you want just the PP, I can sell you that on it's own.

My plexi panel is vey similar to the 10W. I have a 10W in my shop right now. Marshall centered the controls on the panel. Since part of the panel sits underneath the cabinet, the controls are not centered in the opening. I offset the controls .125" so that they would be centered in the opening. If you are going to make your own chassis, then that is not a problem at all.

Let me know if you need pp or chassis (or both)

[zaphod_phil]

IM not going to remove the solder joint from the output tranny to the speakers, so I will take it out and place in a custom box and store under a bed.
If you have ever seen a 10 watt it has the three 'knockout' plugs that you can remove 2 bolts and install a 12AX7 as they did install one when they built the amp. So I believe the 10 watt chasis is the same as the 18 watt chassis.

Yes Scott, I have read elsewhere that the 10W and 18W chassis are basically the same. So you should be able to interchange the two in your combo without any problem.

I'm still struggling to understand the bit about the speaker solder joint and storing something under your bed! Are you saying you want to take the vintage speakers out with the chassis and store them all still hooked together?? That maybe a little extreme/expensive, unless the wattage rating of those speakers is too low to handle the 18W.

Also be prepared for a more aggressive sounding amp then your 10-watter.

[Scott_1930_Popular_10Watt]

Nice to meet you Graydon,

I would want you to make the chassis for me. Sounds like you could make it fit in the amp I have, centered. I guess you would have to design it around the plexi plate? How different is the 10 watt vs. the 18 watt (originals)? I would like to get all needed, chassis, trannys etc. I have my cab and speakers. IM gonna use new Vintage 10 celestions I think. They are about 62.00 each. Is that the best 10" they make for this amp? scott

[zaphod_phil]

IM gonna use new Vintage 10 celestions I think. They are about 62.00 each. Is that the best 10" they make for this amp?

Those are a good choice. You might also want to check out Weber's excellent 10 inch speakers as well, some of which reproduce or perhaps even better Celestions' - maybe the 10" Alnico and/or Ceramic Blue Pups, based on the classic Celestion Bulldog design. See www.webervst.com/models.html. You can also chat on Weber's board with other amp builders for recommendations - www.webervst.com/wwwboard/speakers/spkboard.html

[Graydon]

Scott,

I have no experience with V10s. I have a few G10L35s though and they sound great. The Blue pups from Weber also sound very good. They are actually very good at capturing the sound of a 12" Celestion Blue.

Weber also has a V10SS that is a 50W speaker. I have one of these in my Mini-18W and although the cabinet is very different from the standard 18W cabinet, the V10 sounds great in my Mini-18w. It is loud, and it has a fantastic bottom end. I'll bet it would kill with a pair of them in an 18W.

My chassis will fit in your cabinet although you might have to drill a couple extra holes in the chassis to match up to te mounting locations of the cabinet. Other than that, it should be a drop-in. Contac me by private email for specifics of ordering.