Express done...need help calming the hisss

[M Fowler]

TW is exempt from the twist

[amplifiednation]

Thanks guys.

I'm going KF lazy loop styles on the heaters. Worked well on the rocket and mini express i built.

I want to go over the top of the socket on V1's plate but i guess it might be better to keep that wire longer.

Hopefully the amp fires up this week. i still need a bias trimmer of the correct value.

[T Wilcox]

AH I see

Ive been in the D section too long

So would the twist take away from the TW sought after tone?

Todd

[M Fowler]

You should at least put one or two twists in the first tube's heater wires though. Right now you don't have any twist.

[amplifiednation]

guess i got a little too lazy loop. loops added. it's not quite as pretty, but better than unsoldering those 4 and 5 pin connections

here's the power board. got it a little close to the fuse holder, but it fits. i threw some silicon on the fuse terminal.

i can't believe how tight everything is in this amp.

i used PT clippings and higher rated wire for the full on B+ lines.

[godi]

Hello Taylor

That big white ceramic resistor that replace the choke can run pretty hot, your high voltage and bias wires should be route differently to avoid theses wires to melt from the resistor heat.

Other than that, it look very nice !

[amplifiednation]

Thanks for the help guys.

Godi, I ran those wires under the board, wrapped my heaters a little better.

I finished up the amp today and it fired right up! I need to bias it but it sounds good and it is LOUD. Pretty psyched to have the Express be my first amp to not need any troubleshooting

I will post pics after the weekend.amp was stable on the bench even with the lid off. Can't wait to try some Nos glass, I got a pair of seimens

Thanks everyone for your help with my build. This forum is the best.

[M Fowler]

Great job Taylor enjoy. Might need to figure out which speakers sound the best.

[amplifiednation]

Mark, thanks for all of your help bud

[amplifiednation]

So the Express amp is up and running quite well! I forgot to wire up the shorting input jack correctly, but that was an easy fix.

Other than that the amp sounds great. It has a ton of ballz!! KF was not joking around. All of the controls seem to work nicely together...I'm not getting a lot of response from the prescence control, but i'm going to give it a couple weeks before i change anything.

what i would like to change is the amount of HISS that i am getting. I am not getting any hum, and the amp is stable even when cranked all the way up, but the hiss is pretty evident. I realize they hiss, it's a high gain amp, I'm just curious as to what I can do to make it hiss less.

I read around the forum and I know I will need to find some other tubes to try. If I pull V1 the hiss completely goes away...that is just normal through, right? The hiss also completely goes away with the volume turned all the way down.

Can improvements in lead dress be made? I chopsticked my way around the amp and didn't find any wires that made a difference when moved.

Please let me know any suggestions for fine tuning this loud mutha.

I have some nice NOS tubes I will put in tomorrow and rebias.

thanks guys. My secondaries were right on and most of my tube readings were good too, I was a little low in the rest of the amp, but probably nothing too concerning.

I used Pacifics.

[Tone Lover]

Tubes make a huge differance with anything high gain some tube rolling is in order to find the best low noise one you have.
Bill

[Bob S]

Looks great Taylor.
My express bright switch wiring was very touchy.
V1 was critical - I probably tried 30 tubes there before I got it somewhat under control. NOS 7025 & 5751 gave me best results. Less gain with the 5751 though. Still enough gain for me.
Stick with it - you'll tame the beast.

[amplifiednation]

Thanks guys... I will try the 7025. I have a bugle boy in v1 now, its better, but still hissy. Put a "rogers" mullard, I think, in V2 and RCA 12ax7 in v3

I am getting more change with the presence control which is cool.

I put in a pair of Siemens el34s that I bought specificaily for the build and put that amp though the paces. Man is it loud! The controlled feedback is amazing. I cant wait to play with tubes more. Wife should be at work tomorrow...muhahahaha

Amp gets a little squeely at full volume when the presence or treble is cranked, that was a relief, I was getting nervous it was too stable. It is amazing you can tap the chassis and hear it through the speakers

[billyz]

Thanks guys... I will try the 7025. I have a bugle boy in v1 now, its better, but still hissy. Put a "rogers" mullard, I think, in V2 and RCA 12ax7 in v3

I am getting more change with the presence control which is cool.

I put in a pair of Siemens el34s that I bought specificaily for the build and put that amp though the paces. Man is it loud! The controlled feedback is amazing. I cant wait to play with tubes more. Wife should be at work tomorrow...muhahahaha

Amp gets a little squeely at full volume when the presence or treble is cranked, that was a relief, I was getting nervous it was too stable. It is amazing you can tap the chassis and hear it through the speakers

I would shorten the plate wire to V1 , run it over the top of the socket. You can also go with a 1w plate resistor. A dale RN65 is 3/4w and very quiet, good mojo too.

If you really want low noise, Parallel the V1a/b, use 2 100k plates parallel for 50k, and use paralled 1.5k for 750 cathode resistors. move the second stage to the unused V2 1/2 . I guarantee it will be very quiet and sound even better. Might not be a true clone anymore.

[surfsup]

Taylor, on your PS board, the photo DSCF4424.JPG shows the top left screw mounted to a standoff that seems to be where the PT would be. How did you mount that?

Are those standoffs attached/welded to the actual chassis plate? In the second photo on this page of the discussion (DSCF4358.JPG) it doesn't seem to be glued/welded to the chassis. Is there a screw holding it down on the other side?