Wow this amp is too loud..

[57goldtop]

I just finished building my express clone on Friday and went through the checklist on the weekend. I used Nick's kit , PVC series caps, toneslut trannies and the mallory filter caps.

I honestly couldn't wait to power on the beast and I went through a check list several times before I had the guts to flick the power on ( since this is my first amp build ever ) , no smoke and the pilot light came on as expected. All my b+ voltages look fine, around 418-425 volts on the 250v mains here in Australia, I have read of others on the forums getting similar voltages. So far I've set the bias to -30v, I'm going to leave it there for awhile until I understand more about the amplifier.

I did have a small problem initially, the actual volume was not adjusting the level, having no effect at all apart from adding some unwanted noise. I fiddled with the tone controls and all of a sudden the volume started working as it should and the strange noises went away with it ( weird ), I looked at the layout to check my wiring and all seems fine. There may be a bad connection somewhere but I can not find a dry connection with my multimeter. So far the amp sounds great and I'm very happy with it, the express absolutely blows my 5150 to bits..

The only problem now is that I have to wait for everyone in the house to leave so I can crank the gain...

[Bob-I]

I did have a small problem initially, the actual volume was not adjusting the level, having no effect at all apart from adding some unwanted noise. I fiddled with the tone controls and all of a sudden the volume started working as it should and the strange noises went away with it ( weird ), I looked at the layout to check my wiring and all seems fine. There may be a bad connection somewhere but I can not find a dry connection with my multimeter. So far the amp sounds great and I'm very happy with it, the express absolutely blows my 5150 to bits..

You won't find a cold solder joint with a multi meter. Use a chop stick and jiggle the wires, that'll find it. I suspect the ground connection to the volume control.

The only problem now is that I have to wait for everyone in the house to leave so I can crank the gain...

Wear yor ear muffs. These things are LOUD.

[drhulsey]

... These things are LOUD.

Is that a problem

[gearhead]

You won't find a cold solder joint with a multi meter. Use a chop stick and jiggle the wires, that'll find it. I suspect the ground connection to the volume control.

Of if you can't quite find it, try reheating some of the solder joints.

The only problem now is that I have to wait for everyone in the house to leave so I can crank the gain...

Wear yor ear muffs. These things are LOUD.

Gotta be honest, I have a hard time defining what loud means.

Either my Express is faulty, am more deaf than I thought, or my sense of loud has been swayed too much by other amps such as 80 watt Matamps (Orange-like). LOL.

[57goldtop]

The pack of 10 chopsticks I brought back from Indonesia are going to come in handy next weekend, never thought I'd be using them inside an amplifier.

Right now the amp doesn't have a cabinet and I'm sitting the chassis on a a couple of sheets of foil on my 5150 box, as it is a plate would not fit over the chassis because the filter caps are sitting a little too high. Does anybody have a reasonable solution ? I was thinking that I could probably move the top 3 caps slightly to one side in order to provide enough clearance for a plate to fit over the top.

I've just noticed that the amp exhibits some 50Hz buzz at the moment especially when the volume is turned up but there's enough info here for me to investigate further and locate the source to at least reduce it to acceptable levels.

One thing that I'm so amazed about this amplifier is how good and different all my guitars sound through it, it is difficult to explain. It seems to adjust based on the guitar plugged in. I've never played an amp that could do that, the Peavey was great when used with a Les Paul or any humbucker equipped guitar but the 54 MB Strat lacked sparkle and clarity.. the notes sounded dull but now the guitar comes to life with this amplifier.

[skyboltone]

Well congratulations mister. What a great feeling indeed to set fire to one and have it work. Good on ya.

Dan

[JammyDodger]

Just a thought....

With the tone controls all the way off, you will have no volume. If you begine to turn the bass, mid or trebll control up just a little it will suddenly come on.

Cheers, Mike

[John C]

...Another (minor) thought:

If you're still in an experimental stage and you want to set and forgot your bias voltage for a time, maybe it's best to set it a little high. In other words, instead of setting it to about -30, maybe you'd rather set it to about -35. It's probably fine either way, but I thought I'd share.

[57goldtop]

Just a thought....

With the tone controls all the way off, you will have no volume. If you begine to turn the bass, mid or trebll control up just a little it will suddenly come on.

Cheers, Mike

There was no volume even with the eq controls adjusted. Something happened when I turned the treble all the way up and I heard a very loud high pitched tone coming from the speaker, I thought I blew the OT at that point but then I began to play with the volume everything started working properly. My friend's theory is that I may have "cleaned" the pots by working them.

I still get a high pitched tone when I turn the treble all the way up only if I have the guitar unplugged... otherwise it works as normal.

...Another (minor) thought:

If you're still in an experimental stage and you want to set and forgot your bias voltage for a time, maybe it's best to set it a little high. In other words, instead of setting it to about -30, maybe you'd rather set it to about -35. It's probably fine either way, but I thought I'd share.

At the moment it's set at about -30.5, I think it sounds best there at the moment. I'm not sure if this is correct but following the advice on the board I measured from pin 5 on the power tubes.

[John C]

If you already have an opinion that it sounds best there, then you're all set.