18 Watt Post 15

I rewired front end of the Lite IIb tonight. Coax is a little more microphonic than I like, but it is quite. NO VZZZT... so I will leave as is for now...until I come across a piece of shielded wire that I find suitable.


Here is a pic of the chassis front..there is a post Phase Inverter Master Volume, a tone, and a Volume. (have almost convinced myself to remove the MV.)





Sounds nice....no noise...
Have a A/B switch on order from Musicians Friend. I need it to use with this amp. The low gain channel had a ton of tone and crunch. But roll the guitar vol to 7 and it clean right up. The High gain channel has a lot more pop to it. So, with the A/B box, I can have a clean, crunch and Lead gain...without doing much. Yeah, I know a lot of folks would say use one channel or the other, or use a Tube Screamer...but the amp has it, and has the tone...so I don't want it to go to waste. Will be playing this one live soon...getting boards tomorrow to work on cab.
k

18 Watt post 14

Well, I couldn't leave well enough alone. I noticed that the low gain channel has a little bit of buzz in it, so I have decided to rewire the input section again. I went and got some smaller shielded coax..was orginally done with a piece of guitar cable...which is very bulky. We shall see how this comes out. I think the noise is from the fact the cabling i used before is stranded and is under some strain with the solder joint being unsupported..so every time I poke it, it crackles..or when is vibrated by music...does same..albet very faintly..still I want it gone.
Will see how it goes.
Let you know.
kirk

18 watt post 13

I got rid of the noise. Took me a couple days of poking around, but I got it. I reflowed the solder on the board. Didn't fix it. I reflowed the input jacks and that didn't fix it. I went and got a chopstick and started poking...found it. The wire going from the input jack to the first preamp tube for the high gain channel was not soldered well...it went zzzzz when i pushed on it. I unsoldered and resoldered the wire and now it sounds ever better than before, more gain and better highs.
Now, back to chopsticking. Why use a chopstick or other similar object? Electricity kills. The voltages in the amp I have been building are over 300v dc...more than enough to kill you. Don't think about using a pencil either...graphite in pencil lead is a conductor of electricity. Chopsticks, wooden dowels, a plasitc rod...anything that won't conduct will work.
Have karate tonight. When I get back I plan to record the amp and post the clip and some new photos.
k

18 watt post 12

I could not stand it. I got up this morning and went over the layout in about 15 min. and made sure my ei's were dotted and my tee's were crossed. Went and got my mimi mass (attinuator/dummy load)...flipped the 18 watter upside down and plugged ac power and the MM in. NO tubes-flipped the switch. Measured AC and heater voltages...350 vac to the rect pins (yeah thats high, but no load form tube heaters)...checked heaters on all sockets..hmmm..looks good so far. Popped in the EZ81 rectifyer tube...Voltages to the PT and pretube sockets look good. Put in the el84s...still looks good. Put in the pres...all voltages look good!
Hooked up a speaker and with no guitar...cut the vol up...a little faint ac humm...ok, good so far...plugged in a guitar... 1/2 up..jangle jangle...I'm liken it!....wide open.....HOLY COW!
I started playing "ALL RIGHT NOW" ...and the tone was so there...backed the vol off and it just purrs...OH YEAH baby...das what I'm talking about. There is a little overring (fuzz after notes)..probably a cold solder joint...will shorten a couple wires and reflow the joints in the morning..but all I got to say is....YES....that is how a Marshall 18 is supposed to sound...at least as far as the internet recording I have heard of them.....BINGO....
I am in narvana right now...(will get back to narvana after I go cook some hotdogs and watch some fireworks...happy 4th all.)....
MORE LATER....with sound clips.
kw

18 watt Post 11

Cool, got the parts in from AES and finished wiring up the amp tonight....here is what it looks like from the bottom side.

Tomorrow night I will take a copy of the layout and highlighter and go over everything one more time. Friday I plan to test it...hopefully no fireworks. Hope to have a good report on it Friday, maybe even a sound clip.

After it is successfully working and debugged I will begin cabinet construction. Thinking pine, finger joined....with a nice poly finish. I may do something special with the front panel, don't know yet....more on that later.

Bedtime....Later.

Kirk

karate

I have gotten back in to doing karate again, Shotokan specifically. They have been teaching it out at the college and I could just about kick myself for not getting back into it sooner. It provides a good form of exercise and stress reflief. Have a possible test coming up late July..if I am ready I will test..at present I do not feel properly equipt to handle said test. No matter, since there is a test in November I believe. I am currently at 5th kue. There are 10 kues from white to black. If I stick with it I should, if all goes well, be able to have black by the end of 2010...maybe. If not I will keep trying. Beats going to the YMCA and running on a tread mill.
k

18 watt Post 10

Got all the wires to all the pots, sockets, switches and jacks completed. Tonight we put in the standoffs and set the board in. Should take about an hour to wire up everything to the board. Before I do that though I plan to zip tie and shrink tube some wires to make it much neater in there. I have been shortening the wires as I have been soldering them. The shorter the wire, the less the noise.
Did order my 2 .01uf (10nf) 400v caps that were missing and a black Ampeg style handle for the cab. We shall see how it all works out....caps should be here by thursday...I am off the 4th...sounds like the 4th is going to be a day for fireworks..hopefully not from the trannys in my amp.
Here also is some non earth shattering news about the amp. Yes it is an 18 watter...but I have to have a name for what I call it. Instead of a Lite IIb....it shall bear a name plate with the name of "Hamlet".... IIb or not IIb...that was the question...what to build ...since I am a Shakespeare fan...and as the question was put in the play....be true to yourself...and have a nice day.
k