Subthumper

I had a measure up of transformers and I'm gonna have a go at this. I think it's pretty feasible to be able to fit into a box 18" wide, 12" deep and 4.5" high. With the width and depth it may possible to reduce it a bit more although I'm stuck with the height due to the transformers. The amp spec will be kept straightforward, gain, bass ,mid, treble and master volume, bass boost/fat switch and mid shift, 3x ecc83, 4x6l6.fan cooled.
If anyone can think of any other features to shoe horn into it or what type of handles to use please do say.

Sorry I've misled that a bit. I have the bits for a 120 watt amp. I gave the 200 as an example of using a 19" case.

Ok we'll go with 18".

Ok, so what sort of width are we talking? The 200 watt head I built used a 19" rack case which with the wooden case is just over 20.5" wide. I'm sure with a bit of deviance it can be squeezed down in size although will rely on forced fan cooling. Using aluminium for the chassis and case will reduce weight. Any other features anyone would want to include?

I have the transformers for a 120watt head. Making a physically smaller head would be possible although it would still be a reasonable weight. With the transformers I have it would still be a 3U height. Mesa made the 290 a 2u by having custom transformers that fit that height and laying the power valves horizontally, although I have worked on a few of these that have suffered from heat warping the pcbs. However it does interest me as a project/challenge to squeeze it all into as small a box as possible and it was one of the suggestions made to me when i unveiled my 200 watt head. I'll have measure up of things tomorrow and see what can be done.

Why not use the software to design the internals of the cab to obtain an optimum performance but design the outside around the looks of the vintage cabs? Best if both worlds. Used a pair of D140f's many years ago and they always had a very sweet sound. However the modern 15s I replaced them with blew them away, louder, more lows and with the same amp. If I had some now I'd probably keep them for recording.

The 8x10 looks familiar. Shame to put neo drivers in a heavy box, it's still 90lbs!!!

If you download the tone stack calculator from Duncan's amps you'll find the Marshall eq circuit. It gives a graph and shows how the response changes as you adjust the controls, which work very differently to how you might imagine. This may help you understand what effect you are having by adjusting the control and help.with your sound. It doesn't of course take into consideration the response of the power amp and transformer and the speaker cab, and not forgetting the room your in. I have found with most old school valve eq's and amps that it's often more about what you take away than what you try to add. As Bill said though, close your eyes and use your ears.

I have gen 1 compact 15, I love it but still reckon the logo looks more like says BareArsed.

[quote name='Truckstop' timestamp='1419165721' post='2637103']
Played a gig the other week, finished at midnight and then they had a DJ for the last 2 hours of the event and, I tell you, the noise levels actually shocked me. My head was swimming it was so loud! No-one was dancing, everyone was as far away from the dance floor as possible!

It was so unpleasant I actually felt close to tears.




Truckstop

[/quote]
Had this situation last night, except it was the pub jukebox dialled to total distortion playing what felt like three albums worth of Oasis whilst we set up . I don't mind deafening myself but it was truly uncomfortable.

I have the exact ones, will PM you.

Ok I'll see what I have tomorrow.

Hi, I might have something suitable in my workshop, probably off a scrapped marshall. How many do you need? If I have some I'll chuck em in the post. 're your question about the level LEDs, does the amp sound ok? It could simply be a question of the LED drive circuit being at fault. I've worked on a lot of traces of that age and its well worth going over the whole amp and looking for solder joints that are starting to fracture esp the ones on Jack sockets, pots and sliders.
Cheers Just

It is relatively easy, I did it when I built my own 4xkt88 head. You'd think the makers would get wise this seeing as everyone wants to use small cabs now and not old school 4x12s.

I think they're mostly found in hi fi amps. Probably not used in musical instrument amps due to they're expense and possibly less rugged than a kt88 or 6550. I imagine they sound pretty huge.

Shame really ,seeing as it was exposure on here that really launched Barefaced.

Download the tonestack calculator from the Duncan amps page. It's got most of the permutations of tone controls for tube preamps and let's you virtually alter the values and shows a visual graph of the predicted frequency response. Not many give a true flat response except the James circuit which doesn't have a mid control. Most of fender/marshall circuits are quite mid scooped.
Good luck.

Peavey funk out or deoxit (same stuff twice the price). Does the best job out of all the different things that I have tried. Spray out the Jack sockets and any connections to and from pots. A can of this will last year's. A lot of switch cleaners are solvents that can attack plastic inside a pot and dissolve out the grease that gives a pot that smooth feel.

While there are many brands of valves, it must not be forgotten there are only five factories in the world making valves, so whatever you buy it's originated from one of these. I'm not sure who makes the TAD stuff but the Marshall are mostly Shugang from China. Different people say different things about them regarding sound, reliability and value. The shugangs are getting good reviews even from the hifi guys although that's a completely different ballgame from battering the crap out of them with a bass. Personally I've been using Sovteks which are cheap but seem to hang together pretty well, (only had one failure out of a quad in two years). It's worth searching the net for valve suppliers outside of the music industry market as there's some good deals to be had.
In short I'd say beware the hype.

+1 for the mixer, 4 channel behringer should do the trick. If not maybe a keyboard amp.

I'm using a compact with a 200watt valve head.sounds great, nice even response and seems to keep the amp under control too. Loud too ,although another could be on the cards. It's just weird that I now have an amp head that weighs three times the cab weight. The amp is based on the hiwatt circuit so is probably pretty close to the mywatt.

If your near Bristol gimme a shout. I've serviced loads of those old traces and they respond very well to a bit of love and a clean due to their old school build quality and simplicity.

If your near Bristol gimme a shout. I've serviced loads of those old traces and they respond very well to a bit of love and a clean due to their old school build quality and simplicity.

Hi, I'm looking forward to this as I've done a few of my own and am interested to see what someone else's approach is. Is it going to be valve or solid state? All my stuffs been valve but a lot of the process will be much the same. Only problems I had were staying up late working on the damn things,"just one more capacitor then bed" always turns into another hour. The other major thing I'd say is don't start until you have all the bits, as coming back to something either turns into a mistake or gets forgotten or holds up other things when you have to work around a shortage.
Oh and it's addictive. By the time your halfway through you will be planning the next one and working out how you will do it better than this one.
Good luck, it's incredibly rewarding.
Cheers Just

PM'd.