Overpowering Bass on Laney L20t

Erskine

I have a Laney L20t and have an annoying issue with one of the channels.

The amp has a Hi and Low channel. The Hi channel is intended for hi output humbucker pickups, while the low is for single coils. The suggestion is that the Hi channel is attenuated down by 50% allowing you to drive the amp while retaining better clarity. However, I find the Hi channel is causing bass frequencies to be too strong and booming. I have used both a PRS Custom 24 and Gibson ES335 in this channel and both are the same. The Lo channel is much better, so I am wondering if there is a problem with this channel.

Any ideas?

ICBM

Use the Low channel for everything and don't worry about what the manual says.

Erskine

I am kinda inclined to go along with that now. But am annoyed that there is an issue with the Lo channel.

ICBM

Erskine said:

I am kinda inclined to go along with that now. But am annoyed that there is an issue with the Lo channel.

It's not an issue, it's the way the inputs are designed to operate. When you are plugged into the Hi input, a cathode bypass cap is switched onto the first valve gain stage which boosts the gain. Plugging into the Lo input switches this off.

From the manual - 

‘Hi’ stands for high gain. This input is designed for the connection of low output level guitars making it well suited for guitars with single coiled or low gain humbucker type pickups. Use of high gain pickups in this input may drive the preamp too hard causing a "mushy" sound.

Lo’ stands for low gain. This input is attenuated down approximately 50% from the Hi input and is designed for high output level guitars. It is useful in obtaining output that is "tight" not "mushy" from high gain humbucker type pickups. Also use this input for the cleanest full range sound with extended low end response.

The only thing they haven't really got right is that the Hi input can sound too boomy even with fairly moderate-output humbuckers.

EricTheWeary

Erskine said:

I have a Laney L20t and have an annoying issue with one of the channels.

The amp has a Hi and Low channel. The Hi channel is intended for hi output humbucker pickups, while the low is for single coils. The suggestion is that the Hi channel is attenuated down by 50% allowing you to drive the amp while retaining better clarity. However, I find the Hi channel is causing bass frequencies to be too strong and booming. I have used both a PRS Custom 24 and Gibson ES335 in this channel and both are the same. The Lo channel is much better, so I am wondering if there is a problem with this channel.

Any ideas?

ICBM said:

Erskine said:

I am kinda inclined to go along with that now. But am annoyed that there is an issue with the Lo channel.

It's not an issue, it's the way the inputs are designed to operate. When you are plugged into the Hi input, a cathode bypass cap is switched onto the first valve gain stage which boosts the gain. Plugging into the Lo input switches this off.

From the manual - 

‘Hi’ stands for high gain. This input is designed for the connection of low output level guitars making it well suited for guitars with single coiled or low gain humbucker type pickups. Use of high gain pickups in this input may drive the preamp too hard causing a "mushy" sound.

Lo’ stands for low gain. This input is attenuated down approximately 50% from the Hi input and is designed for high output level guitars. It is useful in obtaining output that is "tight" not "mushy" from high gain humbucker type pickups. Also use this input for the cleanest full range sound with extended low end response.

The only thing they haven't really got right is that the Hi input can sound too boomy even with fairly moderate-output humbuckers.

Just as well I read down, I was going to suggest @Erskine had this back to front. So all’s we’ll that ends well. I use mine only really on the high input but that’s with Fenderey guitars. 

Bridgehouse

Sounds like I need one for bass duties  

Erskine

It is confusing, Eric. I occasionally have to think about it myself despite having used this amp for almost 7 years.

I do still think that the issue has got worse. Now that may be because of a change of string gauge [...although I use a mixed set of 11-48s], using different guitars, aging valves or a number of reasons. But it is very noticeable on the E and A strings.

Another thing I would say is that the mention that it is attenuated by 50% is an exaggeration as far as I am concerned. It seems much less than this.

As ICBM suggests, it is maybe as well to make do with the single channel for all.

EricTheWeary

Erskine said:

It is confusing, Eric. I occasionally have to think about it myself despite having used this amp for almost 7 years.

I do still think that the issue has got worse. Now that may be because of a change of string gauge [...although I use a mixed set of 11-48s], using different guitars, aging valves or a number of reasons. But it is very noticeable on the E and A strings.

Another thing I would say is that the mention that it is attenuated by 50% is an exaggeration as far as I am concerned. It seems much less than this.

As ICBM suggests, it is maybe as well to make do with the single channel for all.

I was quite surprised by the 50% figure, I wouldn’t have guessed that at all although I don’t really have a bench mark of what that means in practice. The low input with my strat which has vintage style pick ups seems a bit lifeless, although I don’t have any boost or overdrive pedals on most of the time. 

english_bob

Erskine said:

Another thing I would say is that the mention that it is attenuated by 50% is an exaggeration as far as I am concerned. It seems much less than this.

As ICBM suggests, it is maybe as well to make do with the single channel for all.

As far as I know, "attenuated by 50%" doesn't really mean anything at all as far as it relates to what's happening electronically inside the amplifier. I mean, I get the gist of what they're telling me the difference is, but "attenuated by 50%" is far too vague an explanation to set too much store by.

"Making do" seems like a strange attitude to the situation. For starters, in your first post you got the descriptions of the channels the wrong way round, so you've probably been plugging the guitars in to the "wrong" channel anyway. You still seem convinced that it's broken, when there's a fairly clear explanation from ICBM on why it isn't. The amp gives you two input options, only one of which is meant to be "right" for any guitar, so you aren't missing out on anything by only using the one you think sounds best.

A new set of power amp valves might be a quick and simple spruce-up measure, and it might not hurt to take the amp to a reputable service tech for an overhaul if it's been working hard since you had it.

On the other hand... You've had the amp seven years, you say? Hmm. Both of the threads you've started since you joined have basically been "I kinda want a new amp" at heart. Why does there have to be something wrong with the one you have to change?

ICBM

'Attenuated by 50%' means that the signal level is cut by 50%. (Actually not quite as much as that, looking at the way it works.) This is not the same as a 50% reduction in perceived volume though, that needs a roughly *90%* reduction in signal level, due to the way the human ear responds, so it's not surprising you're hearing less than a 'half' reduction.

It's possible that it has changed due to valve wear - in which case it will probably be worn power valves, although the V1 preamp valve (the one that's directly affected by the switching) could also be weakening. Going up a string gauge will also increase the amount of bass in the sound coming from the guitar.

After seven years of anything more than very infrequent use it's probably due for a new set of power valves anyway, so I would buy a set of those, and one preamp valve. Replace the power valves first (keep the old ones as spares, since you know they at least work), and then once you've heard the result, try replacing the preamp valves one at a time with the new one. If none of them make any noticeable difference I would probably put the new valve in V1 anyway. If more than one makes a noticeable difference then you need to buy another one and change that too.

Erskine

english_bob said:

Erskine said:

Another thing I would say is that the mention that it is attenuated by 50% is an exaggeration as far as I am concerned. It seems much less than this.

As ICBM suggests, it is maybe as well to make do with the single channel for all.

As far as I know, "attenuated by 50%" doesn't really mean anything at all as far as it relates to what's happening electronically inside the amplifier. I mean, I get the gist of what they're telling me the difference is, but "attenuated by 50%" is far too vague an explanation to set too much store by.

"Making do" seems like a strange attitude to the situation. For starters, in your first post you got the descriptions of the channels the wrong way round, so you've probably been plugging the guitars in to the "wrong" channel anyway. You still seem convinced that it's broken, when there's a fairly clear explanation from ICBM on why it isn't. The amp gives you two input options, only one of which is meant to be "right" for any guitar, so you aren't missing out on anything by only using the one you think sounds best.

A new set of power amp valves might be a quick and simple spruce-up measure, and it might not hurt to take the amp to a reputable service tech for an overhaul if it's been working hard since you had it.

On the other hand... You've had the amp seven years, you say? Hmm. Both of the threads you've started since you joined have basically been "I kinda want a new amp" at heart. Why does there have to be something wrong with the one you have to change?

I did confuse the explanation of the HI and Lo inputs but I can assure you that I have not been plugging in the wrong way round. I have even replaced the Lo input on the amp myself when it developed a fault.

Yes I have been considering a new amp. I am no professional but am old enough to enjoy playing guitar and obtaining new gear when I can afford it. I am at that stage just now and was considering a new amp. I am not doing so because I want to dump the Laney and since you have read my other topic you should have read this.

I have switched valves recently -  not new ones but with a set that were in decent order when I switched them over. I did this to check if I could improve things. I also changed the input valves at the same time.

As for making do? I acknowledged the suggestion that ICBM made. There are disadvantages of using the 'wrong' channel as the tone is not as good. As Laney state, if using the Hi input the tone is not as clear - slightly 'mushy' or muddy. However, ICBM is correct, if you can get a better outcome from using the 'wrong' input, then use it. Another alternative I use is the clean channel [through the Hi input] with volume up to create distortion but run the output through an attenuator to pull the volume down. For whatever reason, this does control the bass response on the Lo input.

And your suggestion of taking the amp to a reputable guitar tech? I have considered this and may ultimately go for this. I have spoken to Laney in the past when replacing the input jack and board. I know that I can arrange for it to go back to them for a service and collection charge of £45 plus any large spares costs.

Erskine

ICBM said:

'Attenuated by 50%' means that the signal level is cut by 50%. (Actually not quite as much as that, looking at the way it works.) This is not the same as a 50% reduction in perceived volume though, that needs a roughly *90%* reduction in signal level, due to the way the human ear responds, so it's not surprising you're hearing less than a 'half' reduction.

It's possible that it has changed due to valve wear - in which case it will probably be worn power valves, although the V1 preamp valve (the one that's directly affected by the switching) could also be weakening. Going up a string gauge will also increase the amount of bass in the sound coming from the guitar.

After seven years of anything more than very infrequent use it's probably due for a new set of power valves anyway, so I would buy a set of those, and one preamp valve. Replace the power valves first (keep the old ones as spares, since you know they at least work), and then once you've heard the result, try replacing the preamp valves one at a time with the new one. If none of them make any noticeable difference I would probably put the new valve in V1 anyway. If more than one makes a noticeable difference then you need to buy another one and change that too.

Thanks, ICBM.

I did change the valves last week. there was no noticeable difference and partly for that reason, I raised the issue on here.

I had an old set of output and preamp valves that I changed when the amp was about 1 year old. They seemed to be performing fine at the time but thought I would change them routinely, as I think many people do. There was also a deal on offer of 4 EL84s for £30. So seemed a good time to make a change. Anyway, there is no real difference between the 2 sets of valves.

I also changed the preamp valves last week. I had originally changed these around the same time as the output valves. The V1 TAD Highgrade valve I changed for a Mullard (JJ, I think). The other 2 I changed for 2 JJ ECC83-S. I have put the original TADs back in but don't like the V1 Highgrade TAD, so I will be changing that one back over.

The strings I now have on the guitars are a mixed set. Top/heavy - bottom/light. I am sure that I started using this because of the booming bass business, but can't be sure of that. So, in case anyone jumps in to claim I am contradicting myself, I won't commit on that.

The amp is used around 5 days per week - on average. I play for an hour or two per day. But I do leave the amp on standby for perhaps 5/6 hours of the day so that I can pop back and forward to use it.

To be honest, I think if I was going to replace all the valves now, I would go the whole hog and return the amp to Laney and get them to do a service on it. I could mention the booming bass issue and hear what they have to say. If they check it and want to replace the valves, then that is fine. If they tell me that it is a design issue, then fine too. But to fork out £100 or more and find my booming bass is still there....... well, I am probably as well coughing up to get it checked? And I would not have spent the money and time on doing so myself only then to decide on sending it to them later.

normula1

Which speakers do you have in it? I've an L5t and with the stock Heritage G12/ 30H I wouldn't call it bassy at all. I do like the sound of the clean channel cranked into an attenuator.

Erskine

normula1 said:

Which speakers do you have in it? I've an L5t and with the stock Heritage G12/ 30H I wouldn't call it bassy at all. I do like the sound of the clean channel cranked into an attenuator.

It is the same speaker, I think. Celestion G12H 30W.

ICBM

Those can be a bit loose and boomy at the bottom end, although they are also quite a clear-sounding speaker. If you want to tighten up the bass, try a G12M - either a 25 or Heritage 20 (the H30 is a Heritage), or a G12M-65 Creamback if you want to crank the amp right up - it will stay tighter.

Erskine

ICBM said:

Those can be a bit loose and boomy at the bottom end, although they are also quite a clear-sounding speaker. If you want to tighten up the bass, try a G12M - either a 25 or Heritage 20 (the H30 is a Heritage), or a G12M-65 Creamback if you want to crank the amp right up - it will stay tighter.

Many thanks once more, ICBM.

Maynehead

And try Chinese 12ax7-c preamp valves, they’ve got a really tight low end.

Just another thought, have you tried the amp in another location or room? Sometimes boominess can be caused by the natural reverberation of having the amp in a corner.

english_bob

Do you have / have access to another amp? Could the increase in string gauge mean the guitar pickups need to be adjusted away from the strings a little? Certainly the cheapest potential fix for the problem...

Erskine

Maynehead said:

And try Chinese 12ax7-c preamp valves, they’ve got a really tight low end.

Just another thought, have you tried the amp in another location or room? Sometimes boominess can be caused by the natural reverberation of having the amp in a corner.

No, I have not tried that. Sounds like an idea though, so I'll give it a go.

Do you mean Chinese valves in general?

Erskine

english_bob said:

Do you have / have access to another amp? Could the increase in string gauge mean the guitar pickups need to be adjusted away from the strings a little? Certainly the cheapest potential fix for the problem...

Unfortunately, I don't anymore. I did have a Vox modelling amp but sold it last year. So this is my only one.

I'll try the pickup adjustment, although the PRS PU is pretty far away already as I lowered this some time ago.

Maynehead

Erskine said:

Maynehead said:

And try Chinese 12ax7-c preamp valves, they’ve got a really tight low end.

Just another thought, have you tried the amp in another location or room? Sometimes boominess can be caused by the natural reverberation of having the amp in a corner.

No, I have not tried that. Sounds like an idea though, so I'll give it a go.

Do you mean Chinese valves in general?

I mean something like this: http://www.karltone.co.uk/shuguang-12ax7-ecc83-707-p.asp