Just Finished Express - pics and hiss...

[Paul-in-KC]

All,

I just finished the initial assemble and power-up testing of my first Express (and only second amp build).

I'm pretty happy with it so far - but can't really check it out until tomorrow.

Here's one of the inside completed...
[IMG768]http://i1178.photobucket.com/albums/x37 ... mplete.jpg[/img]


and here's one of it sitting in the cabinet that I bought from Amp Nation...
[IMG768]http://i1178.photobucket.com/albums/x37 ... nished.jpg[/img]

Here's one of the powerup testing (with current limiter)...
[IMG768]http://i1178.photobucket.com/albums/x37 ... esting.jpg[/img]



As I say, I'm pretty happy so far - but I must say there is a fair bit of hiss - like white noise. Not much hum at all, just hiss. It's the sort of noise you would usually associate with a high gain channel or maybe a distortion pedal. Is this typical for an Express?

Thanks,
-Paul

PS - I'll post more after I get to really play/hear it. It was too late tonight when I finished.

[xtian]

Does this hiss mostly vanish if you roll all the controls to zero?

[cbass]

Good job.Nice lookin amp


You will have some hiss.With the volume,treble and prescence turned up.

Should go away once you back the volume down some.

You will find a huge differnce in noise between tubes in v1.

I went through several mullards and sylvainias that worked just fine in other amps before I found a quite one.

[Paul-in-KC]

Does this hiss mostly vanish if you roll all the controls to zero?

If you cut the volume to zero (or near) it mostly disappears. It's also not really noticeable compared to amp volume. I suspect that this is normal for this amp. ???

I have several different tubes to try, I might try swapping them around and seeing if it varies.

Still haven't played with it much (Easter Sunday) - but it's very cool so far.



All build pics are at this PhotoBucket album...
http://s1178.photobucket.com/albums/x37 ... 20Express/

-Paul

[Bob S]

Looks very good Paul.
Some hiss is normal.
V1 is problematic with these amps. V2 can be touchy too.
Get to know her before you change anything.
Have fun this Easter!

[geetarpicker]

It will hiss as it IS a high gain amp! However compared to other amps with similar gain it should hiss less than typical. I noticed if you compare it to a vintage style 4 input Marshall set to similar gain (Express on about half, Marshall wide open) and the tones set to a somewhat similar EQ the Express should actually hiss less. A good way to minimize the hiss at bedroom volume levels is an attenuator. Keep in mind since the amp does not have a master volume you are at gig volume levels from the get go, loud gigging levels at that.

[Paul-in-KC]

It will hiss as it IS a high gain amp! ... A good way to minimize the hiss at bedroom volume levels is an attenuator. Keep in mind since the amp does not have a master volume you are at gig volume levels from the get go, loud gigging levels at that.

Hey Glen - thanks.

Right you are - it is a high gain amp indeed.

Can you suggest your top two (or three) choices for tubes in V1, V2, PI, and Power tubes?

I have a Dr. Z Air Brake coming Tuesday - so, I think that will be helpful to operate the amp at proper levels without all the volume

BTW - My first build was/is Marshall 2204 - it's hard for me to compare the levels of "hiss" (because the 2204 has the master volume) but Marshall seems more quiet. Probably not though if I cranked the preamp volume and just used the master - which I guess would be the best comparison.

Thanks again.
-Paul

[LeftyStrat]

Has anyone ever tried light bulb noise reduction, as used in the Hot Plate?

Seems like it would be a great way to suppress hiss.

See figure 1.15:

http://books.google.com/books?id=DoU2CL ... er&f=false

[xtian]

Probably not though if I cranked the preamp volume and just used the master - which I guess would be the best comparison.

Other way. Open the master all the way, and just use the preamp gain. Now it's like it has no master!

The Hall VVR I put in my Rocket builds is great a removing noise for "at home" use. If you just turn the VVR down about ten percent, a lot of the hum and hiss drops out, and there's still LOTS of power available.

[Paul-in-KC]

Other way. Open the master all the way, and just use the preamp gain. Now it's like it has no master!

Ah - right.

I suspect the hiss would be comparable then.

-Paul

[Big Jim]

I found that my amp likes a RCA black plate 5751 in V1. I also made myself a LONG cable (like Glenn does ...thanks Glen). I'm not sure it helps with the hiss, but you can get away from that monster a little. When you compare the volume with the amount of hiss, it's kind of negligable.
Tons of gain + very few components = some hiss.

[amplifiednation]

Paul,
Congrats the build looks great! My Express hissed a lot when I first built it. I tried a lot of different things, even a parallel gain stage on V1. That helped a little but I lost some tone control.

Keep trying tubes, the mil spec glass can be quieter. The amp is like a tube tester, different tubes are very noticeable.

My Express was so sensitive it even picked up public radio one day with the plate off.

Good luck!

T

[Big Jim]

Paul I forgot to mention, really nice looking build.
Jim

[Paul-in-KC]

Paul I forgot to mention, really nice looking build.
Jim

Big Jim - thanks very much.

Thanks to all for the responses.

Upon further consideration, my current "guess" is that the level of hiss that I am getting is perfectly normal for an Express.

It seems like a lot more than I get with my other amps, but all of those have master volumes.

The ratio of hiss to guitar volume is actually very low (it's just a VERY LOUD amp).

So - I know before I ask this, that tone is in the ear of the beholder and different tubes from the same batch will perform differently, BUT I'd still like to hear what you guys have found to work with your Express.

I'd just like a shorter list than every possible 12AX7-type tube ever made (and 7025's, and 5751, and...).

My sense is that I will need several copies of every type of tube that I want to try - so this is going to be expensive regardless. But I'd like to know which make/model tubes are most likely to work well.

What are your "go-to" tubes for V1, V2, and PI?

Thanks again to all.
-Paul

[paulster]

What are your "go-to" tubes for V1, V2, and PI?

Tungsrams all round. And pay particular attention to V1.