Should I build an 18 Watt Marshall kit?

[maiden_fan]

I really want to get into amp building and tweaking. I have a few books that I have been reading etc. I was thinking of building this kit:

 

http://ampmaker.com/sl-18-18w-superlite ... 486-0.html

 

And as it is so simple, playing around with it to see how tweaks affect the sound. With a build like this am I going to be able to say add an effects loop, add a resonance knob or a PPIMV? And generally increase gain or is it a poor platform for that?

 

Cheers Tony

[PaoloJM]

Yep, that's a good place to start. I built something like that.

 

PPIMV works well in that circuit. If you're installing a PPIMV then there's no point in a resonance as it wont do anything unless you're up full.

 

As for gain, I found gain up to JCM800 level works well but it's not a good platform for modern high gain. It just seemed to lack the punch and definition required no matter how I tweaked the preamp. Of course you might find otherwise.

 

The some videos of my one are on my uTube page below if you're interested in having a look. I did mine with three preamp valves and made an additional switchable set of gain stages. No loop though.

I didn't see the need as the amp is only used up to moderate gain and then pushed with an OD.

[maiden_fan]

Thanks for your info. I really only want VHII levels of gain. That's interesting about the PPIMV though. I may do a presence knob instead.

[PaoloJM]

Presence doesn't work either.

 

PPIMV sit's within the power amp. The result is that lowering the volume reduces the amount of negative feedback of the power amp by a log factor. That renders any feedback based controls (resonance, depth, presence) inactive unless the PPIMV is up full.

 

There's always a catch, eh?

[Zozobra]

I'd say a PPIMV in an 18 W amp isnt really necessary. I've not dealt with the guy who runs that site but he seems like a stand up guy and from what I can gather the instructions are very good and clear.

 

The thing with that amp is that you only have 2 12ax7s in there, presumably once is for a long tail pair phase inverter which only leaves you with 2 gain stages to play with. If you wanted to step the gain up a notch but dont want to add another pre you could swap to use a cathodyne PI which would liberate a triode. You then have three stages so you can get quite a bit hotter and even fanny about with cold clipping if thats your bag but as paolo said, its not really what this thing was made to do.

 

A loop would require another tube adding unless your happy with using an SS buffered loop. I think the ampmaker chassis are drilled for more slots than are used so thats shouldnt be an issue. There are some good loop designs in merlin blencowes book which I recommend buying if you havent already. However, I assume this amp has a fairly dirty power section so a loop isn't going to sound too great. To remedy this you can up the negative feedback (within reason) or you can clean up the PI operation but you'll start to lose the character of the amp then.

 

Its probably not going to do what you want it to out of the box and to get it where you want will take fairly significant reengineering and a fair bit of redesigning but it will be a good learning experience just to build it stock and you'll have a nice test bed to change components around in.

 

I'd say do it, learn from it and then start a scratch build when you're confident. My first amp build was way too complicated and it help me back. I've been starting a scratch build since forever now but I've been too busy to sit down and really design the thing properly. I may well just build a 4 stage preamp to dick about with as I can paint as I go much more easily.

[Edge11]

HELL YEAH!

[Pepi]

I got the itch to build an 18 watter a few years ago. It sounded good but it was just a one trick pony. I got bored with it quick and sold it. I just don't really like the EL84 tubes. Big bottles for me

[Dolf]

Yes you should

[RupertB]

18w is a great choice for a first amp. Somewhat similar to my first one, a Lightning 15.

 

Yes, it would be a good platform for tweaking & modding.

[chris_d]

They make great first builds. They are simple, loud, and sound good.

 

That said, i agree with Pepi. Some folks hear the 18w and it is exactly what they were looking for. I found it somewhat limited for what i wanted to do.

 

In the end i rebuilt my 18w as a sort of AC30/Matchless/Fender frankenstein thing that runs a 6V6 or 6L6 output.

 

If i were to do it all over again, knowing what i know now, i might have built a Matchless Lightning first. It is not measurably more complex a circuit, and for my purposes, but i find it more flexible and useful.

 

For VH sorts of sounds though, you might consider building something more like this though: http://mhuss.com/Plexi6V6/index.html

 

Another potential source, would be the 6v6 based A15Mk1 kit from Madamp: http://www.madamp.biz/ This is also an amp that you could later use as a base for making quite a few interesting modifications to, once you are more comfortable with the building and modding.

 

Either one of those would get you much closer to what VH sounds like, in my opinion. I found the main issues that i had with EL84s was that 1. they don't last very long, and 2. they don't have very much bass content, particularly as utilized in the Marshall 18w. For a very specific type of playing style, they work wonderfully, because they cut through a mix so well. But in the end, i did find that they weren't doing everything i was looking for.

[Badside]

Presence doesn't work either. PPIMV sit's within the power amp. The result is that lowering the volume reduces the amount of negative feedback of the power amp by a log factor. That renders any feedback based controls (resonance, depth, presence) inactive unless the PPIMV is up full. There's always a catch, eh?

 

The Marshall 18W circuit does not use negative feedback

[Shask]

I agree that amps with the little power tubes never sounded great to me. They lack of the punch and depth of the bigger power tubes.

 

But, it depends on what you want, and I think whatever you built first will be a huge learning experience. My first amp was a 5W high gain amp. I never really use it, but it sounds decent for what it is. I highly prefer the 100W amp I built

[chris_d]

I agree that amps with the little power tubes never sounded great to me. They lack of the punch and depth of the bigger power tubes. But, it depends on what you want, and I think whatever you built first will be a huge learning experience. My first amp was a 5W high gain amp. I never really use it, but it sounds decent for what it is. I highly prefer the 100W amp I built

 

Worth noting, the relative price of entry for a lower wattage build is also very desirable. If you are going to make a noob mistake and accidentally destroy an OT the first time you fire it up after building it, it is always much nicer to be able to get a new one for $30-40, as opposed to $100+ (minimum) for a bigger amp's transformer. That sort of thing.

 

For that, i like the middle ground of the 6V6. Compared to the 6L6 or EL34 is has a bit less boom to it, but compared to the EL84, it has quite a bit more. And as a lower wattage power tube, the transformers it needs are very affordable.

 

You can get an awful lot of flexibility out of a 20w 6v6 circuit, IMO. And you can run it flat out easier also.

 

On the other hand, if a fellow can afford to, for VH tones, a 50w or 100w plexi build with a Lar/Mar master volume can make an awful lot of a fine noise. (Just make sure to get it right the first time.)

[Shask]

I agree that the bigger tubes is a much bigger commitment, buildwise and cashwise. I just think it depends on your goals. A lot of people expect to build a little amp and expect Recto/5150 tones, and it just isnt gonna happen.

 

I have never tried 6V6's, but they sound interesting.

[PaoloJM]

The Marshall 18W circuit does not use negative feedback

 

If he planned implementing resonance or presence controls, as he mentioned, he would need to use some.

[Kitarist]

Or you can get something from Ceriatone also but for the first time the ampmaker is really great. If you want to do some mods you can always ask around the forums and such