mission 5E3

[rudutch]

I am about 90% done BUT

there are 2 - 100k ohm(?) reisitors that go to the 6V6 sockets

anyone have a picture of how they did this, they appear to be flying in the drawing and that does not seem right

Thanks in advance

[Kap'n]

Hmm.

Can you shoot me a schematic/layout?

anwari at snet dot net.

[rudutch]

sorry..
I will have to call Bruce after work

[Kap'n]

The only 100 ohm resistors I know of in a 5E3 would be for the filaments, if you're doing a modern ground scheme, as opposed to to doing the fifties version.

That's usually done at the pilot light, not the power tubes. That's why I'm a little confused.

[ziess]

Kap'n, do you mean putting 100 (k) ohm resistors in series with the filament wiring?
Why would this be done and what would the result be?

Thanks,
Tommy.

[Kap'n]

No, 100 ohm resistors run from each side of the filament winding to ground to create a virtual center tap for the filament winding. This reduces hum.

Don't do this if your filament winding has an actual center tap grounded.

[ziess]

Ah, I see, thanks.

[rudutch]

they mount on the socket. - will post pin numbers is anyone really cares. The thought of 'flying' reisistors (unsupported) inside a combo amp did not sound right.

He did have a blurred photo in his online documentation

thx, kap'n

[Kap'n]

Did they go to the filament wires (pins 2 and 7)?

They sort of have to be flying if they go to ground.

[rudutch]

Did they go to the filament wires (pins 2 and 7)?

They sort of have to be flying if they go to ground.

going by bad memory, that sounds right. It made sense after someone explained it but the way it was drawn was very confusing.
they go (each) between 2 pins something like 2-7 8-3 (??)
I wrote it down

Last technical electonics training was 1979 for me, then blend in
20+ of electrical drawings, one lines, ladder diagrams... switch back to electronics - schematics and component diagrams

It's amazing I can still dress myself in the morning, I'm as screwed up as a foot ball bat.

I did find where I had missed a resistor, throwing my triple check system out the window...

It will be interesting when I turn it on

[rudutch]

it works!
similar to my ampeg revererocket. Darker and smoother, not as much punch. was hoping for a bit more clean headroom but 'dime it' and run my P-90 melody maker... wow!

I underestimated how much effort this took, I would not say it was 'easy'

[Kap'n]

Congratulations!

If you want more punch, try messing with the value of the 5K resistor between the first two filter caps. Lower = less sag, more punch. I've gone as low as 500 ohms with this.

You can also add more punch/focus by trimming some of the low end. Reducing the value of one or both of the 25uF bypass caps, and/or the 0.1uF coupling caps in the preamp.

[rudutch]

Tried it in a band environment - I must have something wrong, not near loud enough. It sounds cool but I am guessing less than 5 watts.
I about matched the volume of an Epi Valve Jr through a 1x12 and I was using a 2x12.... another project

[Kap'n]

Tried it in a band environment - I must have something wrong, not near loud enough.

Key to these is learning the volume controls.

Also, the aforementioned 'sag' resistor causes squash. At some point, the harder you hit it, the quieter it gets.

[rudutch]

I suspect the rectifier tube did not like what I did to it (oops, but only for less than 3 seconds) I will take some readings. I ran it through a vintage 30 and through a pair of g75t celestions, I should not have been drowned out by a valve Jr. Both of those speakers are 96-99spl

It sounds good, nothing glowing red, smoking, or other such catasrophies

I am adding this to my list of valuable experiences

[rudutch]

Okay, I am gaining here..

I had a speaker issue, ran it through a Celestion vintage 30 raised up off the floor, not overly loud but it works. I have ordered a cabinet from Bruce and I still have to get the volume control issue fixed..
It definitely has a unique sound..
and my $500 budget is out the window too

[rudutch]

update #2

got the volume controls straightened out still have an issue with the tone control. I got the cabinet (very nice), installed a vintage 30.

I wanted a cannabis rex (103Db SPL)
but the Celestions (100Db SPL) will do for now.

The overly distorted issue is resolved, tone contol is next.

I will post photots sometime soon.

I'm glad I'm not paying for my labor on this

[Don]

As much as I like building things I'm glad I had one built. I still get to have a little fun though. I disassembled the amp and put 2 more light coats of lacquer on the tweed and replaced the cheap Weber plastic pilot light this weekend (now I have the blue jewel that I had on my Princeton Reverb on it).

I had the whole amp apart and forgot to install the tube chart though!

[rudutch]

my intent was:
1) have a desirable amp when completed
2) actually 'build' one (yeah, it was a kit)
3) increase my knowledge of amps
4) be able to easily mod / change in the future

I also understand why they don't build them like this anymore, it is labor intensive as h*ll.
It should last for years and I can honesly say not too many people can do this (and have it work afterwords).

I have a better understanding of how these work but certainly not a master

[Don]

my intent was:
1) have a desirable amp when completed
2) actually 'build' one (yeah, it was a kit)
3) increase my knowledge of amps
4) be able to easily mod / change in the future

I got 1, 3 and 4 out of my experience. I had been looking at the Mission kit for a while now. I don't doubt that I could build one. I'd go through the same debuging process as you though.

Mine was built out of a guy's spare parts and some new parts. The cabinet is new, dovetailed, built by a guy in Maine. The builder covered it very nicely, tinted it and made the baffle. A pro amp tech friend of the builder who knows tweed amps wired and assembled the chassis. It has a Hoffman chassis (nice piece!), a slightly used Weber 12A125 speaker (awesome!), even a Fender Deluxe, Fullerton California logo (cool, though not usually how I do things). There are quite a few Weber kit parts in it (like the cheesy plastic pilot light). The tubes are pulls and NOS.

It's a nice amateur/semi-pro build. I actually like that there were a few little things for me to do on it.

The best part is that it only cost a little more than a Mission kit and I got to play it within a few weeks of deciding that I wanted one and it was bullet proof right out of the box (knock on wood).