Amp volume issue

lincolnblue

I have a Laney Cub 10 and yesterday when playing it found a weird problem. It was unusually really quiet. I know it's only a 10-watt amp but I had the gain and volume on max and it was no where near as loud as it should be. Could this be a value issue? Or is the amp knackered?!

ecc83

A good rule of thumb for a 5-10 watter with any decent sort of speaker is...Can you easily hold a conversation over it in the same room on full beans?

10W into a fairly poor 95dB speaker is still 105dBSPL/mtr and that's loud!

Dave.

lincolnblue

I was playing it at my church and usually I don't even have it half way. But for some reason it was so much quieter yesterday - no other changing factors. 

ICBM

Could be either.

Did the amp sound OK but quieter, or was it more or less distorted than usual, or distorted in a bad way?

Are both power valves glowing properly? - they should be orange in the middle and usually a little blue around the inside of the glass, although you may need a dark room to see that. They should *not* be red on the outside of the grey plates.

Are all the preamp valves glowing properly? - two spots of orange at both the top and bottom of each valve.

Even if all the valves appear to be working properly it's not a guarantee that it isn't a valve problem.

Were you at a loud gig the day before?  

lincolnblue

I'd not used the amp for a month or so - it had just been sitting in my house. I didn't look at the valves so will do that with lights off, curtains closed etc.

It was more distorted but only because I needed to have it turned up to get a decent volume. 

lincolnblue

ICBM said:

Could be either.

Did the amp sound OK but quieter, or was it more or less distorted than usual, or distorted in a bad way?

Are both power valves glowing properly? - they should be orange in the middle and usually a little blue around the inside of the glass, although you may need a dark room to see that. They should *not* be red on the outside of the grey plates.

Are all the preamp valves glowing properly? - two spots of orange at both the top and bottom of each valve.

Even if all the valves appear to be working properly it's not a guarantee that it isn't a valve problem.

Were you at a loud gig the day before?  

I had the amp on tonight. Each valve glows orange at the top and bottom. I'm really not sure what's wrong. At one point it was OK, then it was majorly hissing if gain or volume were over half way -the tone of hiss altering with the tone control. With gain and volume up all the way and guitar plugged in it went into natural feedback without playing, then at half way on both gain and volume it was very quiet...quieter than it should be.

ICBM

lincolnblue said:

I had the amp on tonight. Each valve glows orange at the top and bottom. I'm really not sure what's wrong. At one point it was OK, then it was majorly hissing if gain or volume were over half way -the tone of hiss altering with the tone control. With gain and volume up all the way and guitar plugged in it went into natural feedback without playing, then at half way on both gain and volume it was very quiet...quieter than it should be.

That sounds like a knackered preamp valve, one of the two that's in the foam rubber shock-mounting (or if it's missing, the ones under the input jacks).

If you don't have a spare valve, try swapping the third one for the second one and then for the first one - it probably won't fix it, but if the problem changes in any way it means it's almost certainly one or both of those valves. If it doesn't change at all it's unlikely to be a valve. It won't be the power valves if the problem is affected by the controls (other than presence, which is a power-stage function).

lincolnblue

ICBM said:

lincolnblue said:

I had the amp on tonight. Each valve glows orange at the top and bottom. I'm really not sure what's wrong. At one point it was OK, then it was majorly hissing if gain or volume were over half way -the tone of hiss altering with the tone control. With gain and volume up all the way and guitar plugged in it went into natural feedback without playing, then at half way on both gain and volume it was very quiet...quieter than it should be.

That sounds like a knackered preamp valve, one of the two that's in the foam rubber shock-mounting (or if it's missing, the ones under the input jacks).

If you don't have a spare valve, try swapping the third one for the second one and then for the first one - it probably won't fix it, but if the problem changes in any way it means it's almost certainly one or both of those valves. If it doesn't change at all it's unlikely to be a valve. It won't be the power valves if the problem is affected by the controls (other than presence, which is a power-stage function).

Thanks! I changed one of the pre amp Valves about 6 months ago so I will change the other...unless it's best to do both at the same time?

ICBM

No, just change the faulty one. You can't assume it isn't the new one though.

lincolnblue

ICBM said:

No, just change the faulty one. You can't assume it isn't the new one though.

Ah OK so just try a new one in each valve slot until it works properly? Thank you!

lincolnblue

ICBM said:

No, just change the faulty one. You can't assume it isn't the new one though.

Well last night I changed the valve - changed the original one that was in there and it now works fine. Thanks for your advice! I really love the sound of the amp - not too many of them around I don't think. 

lincolnblue

As per the origins of this post, I have had some issues with my Laney Cub 10. I changed the pre-amp valve and all was ok. However, when I was playing through it yesterday, it was really quiet again. Had the guitar plugge dinto the High input and with the gain and volume to about 7 it was only just about a decent volume. Usually it's far too loud at that volume (it's a VERY loud amp for its size)

The hiss/distortion sound has gone, it's just very quiet

Any ideas what I could try next? 

DJH83004

Hi, just backtracking on the original thread, and I want to be sure I am thinking about the right amp first of all, the Cub 10 has two 6V6 output valves and two ECC83s, (1 preamp and 1 phase inverter) - is that the configuration of your amp?.

ICBM

I've had a bit of trouble with the PCB jumper connectors on these amps.

This won't be easy to fix or even diagnose yourself really though. These amps aren't particularly easy to work on, so if you've tried changing all the preamp valves (again, it won't be a power valve since there are two and one dead one won't make the amp that quiet), then it's probably time to take it to a tech if you're not handy working on PCB amps.

Ah - just remembered, these amps also have an extension speaker jack which disconnects the internal speaker - poor design in my opinion. Try putting a spare cable in the jack, wiggle it and take it out again. If that fixes it you need the jack cleaning, re-tensioning or replacing depending on how bad it is.

lincolnblue

DJH83004 said:

Hi, just backtracking on the original thread, and I want to be sure I am thinking about the right amp first of all, the Cub 10 has two 6V6 output valves and two ECC83s, (1 preamp and 1 phase inverter) - is that the configuration of your amp?.

Yep that's right

lincolnblue

ICBM said:

I've had a bit of trouble with the PCB jumper connectors on these amps.

This won't be easy to fix or even diagnose yourself really though. These amps aren't particularly easy to work on, so if you've tried changing all the preamp valves (again, it won't be a power valve since there are two and one dead one won't make the amp that quiet), then it's probably time to take it to a tech if you're not handy working on PCB amps.

Ah - just remembered, these amps also have an extension speaker jack which disconnects the internal speaker - poor design in my opinion. Try putting a spare cable in the jack, wiggle it and take it out again. If that fixes it you need the jack cleaning, re-tensioning or replacing depending on how bad it is.

Do you mean to put a cable in the extension jack and wiggle it? Can it be any jack cable or would i need to use a speaker jack?

ICBM

Yes. Any cable.

lincolnblue

Thanks. I'll give that a try. I was in touch with Laney who suggested I replace the output valves but I think I'll try your suggestion first! 

ICBM

lincolnblue said:

I was in touch with Laney who suggested I replace the output valves but I think I'll try your suggestion first!

It's almost certainly not the output valves - that's just a stock answer from someone who hasn't properly thought about the problem.

In an amp with more than one power valve, if a power valve fails you will still get a fair amount of signal, and at low to medium volume you may not even hear a lot of difference. It's only when you push the amp hard enough that the remaining valve can't cleanly amplify the whole signal that you'll hear it - a more distorted sound and less maximum power.

To get virtually no sound at all, both power valves would have to fail at the same time.

DJH83004

Have not worked on a 10, but have a 15, which I would imagine is from the same generic family. As ICBM has previously stated there are quite a number of connectors linking the boards, so a thorough check of the connectors and pins plus preamp valves would be a good starting point

lincolnblue

DJH83004 said:

Have not worked on a 10, but have a 15, which I would imagine is from the same generic family. As ICBM has previously stated there are quite a number of connectors linking the boards, so a thorough check of the connectors and pins plus preamp valves would be a good starting point

Thanks. I assume it's safe to jst take out the valves, have a look around etc?