Finished My Express OMFG

[passfan]

You guys are after my heart here now. When they burn up just go buy another set.

[passfan]

Anyone see a problem with leaving the 1 ohm cathode resistors on the output tubes for biasing ?

[sst4270]

Once again. Thank you for the education gentlemen. Sometimes I just need to be a little less concerned with then numbers.

Steve

[sliberty]

Anyone see a problem with leaving the 1 ohm cathode resistors on the output tubes for biasing ?

Should be no problem. One of my builds has them and sounds superb and has been totally stable.

[mac0611]

6L6GC's dissapate 30W. At 60% bias for safety's sake, that would be 30*.60=18W. 18W/410V=44mA. Plus, the screens are running at around 390V. The overall current running through the tube is less than if a choke was used. W/ a 6k6 primary, max transmission is not being reached=even less current draw. They will hardly be breaking a sweat.

[paulster]

Anyone see a problem with leaving the 1 ohm cathode resistors on the output tubes for biasing ?

Unless you're going for an absolutely spot-on replica then leave the 1ohm resistors in. It makes for much easier biasing and doesn't affect tone.

[passfan]

Well I aired it out good this afternoon for about three hours straight at mostly half to full and all I can say is ....!!!!OMFG. This amp makes playing effortless. I don't have to try as hard to let my emotions through into my playing. It will take a little getting use to but I love the finesse this amp demands. Developing a lighter touch will only make me a better player.

I noticed a 10 ma difference in my output tubes when biasing. Is this normal or just a crappy matching job?

[eddie25]

Crappy matching job I guess. Though they tend to drift, so unless the dealer breaks them in for a good amount then it happens. As a matter of fact I've considered asking for tubes about 7-10ma apart since it gives them a cool sound for amps meant to be played with lots of gain. I just bias one a little cold and one maybe right at 70% or a tad higher.

[M Fowler]

Okay I have to ask why no one has hounded you after two pages for pictures and gut shot? Seems odd from this crowd.

[jjman]

Anyone see a problem with leaving the 1 ohm cathode resistors on the output tubes for biasing ?

Unless you're going for an absolutely spot-on replica then leave the 1ohm resistors in. It makes for much easier biasing and doesn't affect tone.

Also perfect for placing scope probes.

[passfan]

Here are some pics. My file sizes are too large so I'll link you guys to my photobucket page. You can feel free to poke around in the other albums as well. Their all based around different builds of mine with some of my guitar builds as well. enjoy

http://s705.photobucket.com/albums/ww56 ... s%20Clone/

[Mont]

Congrats on the amp. I finished my Express a few weeks back and I juice my grunties everytime I take her out. You got to name her now. I named my Express Nasty Whore!

[Structo]

[IMG768]http://i705.photobucket.com/albums/ww56 ... C03689.jpg[/img]
[IMG768]http://i705.photobucket.com/albums/ww56 ... C03688.jpg[/img]
[IMG768]http://i705.photobucket.com/albums/ww56 ... C03687.jpg[/img]
[IMG768]http://i705.photobucket.com/albums/ww56 ... C03686.jpg[/img]

[M Fowler]

Hey I like your originality.

I am going to use cap cans on my next Express as well as one large board all the way across for all the components or PCB Split the transformers up to reduce noise, no pot ground buss, insulated input jack and a few other things.

And red wire.

[passfan]

Hey I like your originality.

I am going to use cap cans on my next Express as well as one large board all the way across for all the components or PCB Split the transformers up to reduce noise, no pot ground buss, insulated input jack and a few other things.

And red wire.

What do you mean by original ? I used what I had lying around in the shop. Isn't that what Ken did I figure I actually had to spend a couple hundred dollars. The two samwas sticking off the end of the card are due to a JJ 40/20/20/20 that hasn't come in yet. Had to extend some transformer leads and my heater winding has no center tap so I added a voltage divider off the B+ for the preamp to positive reference it and kill my hum. Other than that rule number one when building a high gain amp, follow the map, explore later;)