Less power for studio with Laney VC30

tnt76

Member
2005-05-25 12:33 pm
Italy
Hello.

Yes, i need less power from my guitar amp :bigeyes:
How I can obtain this result?

The final stage is a double push pull with EL84.
If i remove a brace of this, may i have some problem?
Obviously the sound will be unequal beyond that less loud, but can i break my lovely amp?

Excuse me for this stupid question, but i'm not a very expert of tubes amp....:rolleyes:

This is the complete schematic supplied via email by Laney.

VC30
 
This amp is cathode biased, so if you pull half the tubes, you also need to alter the value of the cathode resistor, not to mention connecting the speaker to a lower impedance output.

Even if you could, pulling half the tubes and so half the power results in only 3db less loudness. One alternative is a power attenuator, several brands are available such as the Marshall Power Brake, the Weber Power Mass, the Scholtz Power Soak, and others. These things soak up the power and pass on only a portion of it to the speaker.

Another option is to use a less efficient speaker. Cutting power in half is a 3bd reduction in sound, but using a speaker that is 3db less efficient has the same effect. If you replace a speaker with 100db efficiency with one of 94db efficiency, it is the same as cutting the amp power to 1/4 the original level.

Keep in mind that power is not loudness, so half power will not be half as loud, it will be only slightly less loud.

ANother studio trick is to isolate the amp. Put it in a vocal booth or something and mic it. Ther are commercial products - or make your own - that amount to a speaker and a microphone in a closed container. It is real loud inside, but outside it makes little noise. I have a friend who loves the sound of his amp cranked to the sky, but hates how loud it is. (And the clubs will not allow it that loud.) He puts his speaker outside in his van and runs his signal out to it and has a mic out there to feed the sound back into the PA system.
 
What type of sound, at lower levels, are you trying to produce. Are you trying to get the volume down to conversatioal levels? Also, is loads of distortion part of the plan? The obvious answer is to turn down the master volume but if that's what you wanted you would have allready done it. Let everyone know what you are trying to do and someone here will probably be able to help.
John...........
 

tnt76

Member
2005-05-25 12:33 pm
Italy
Hi John...
I would like less volume just for obtain a more distorced signal at lower levels of SPL.
The problem is that my amp don't have the master level pot, as you can see looking at the schemtic.

I've searched some comments on my amp on Harmony central, and some peoples use the effects loop to obtain my objective.
So i'm planning to use this way, wath do you think about?
I'm thinking to disconnect the resistor R49 from the TL072 and rewire it on the level FX pot, or maybe is better rewire P43 with P53 and disconnect R49?

i'm little confused...:xeye:
 
Well, I looked at the schematic and I don't see how putting a volume pot on the effects loop would do what you want. I'm guessing that the type of distortion you like is coming from the overdriven output tubes. If this is the case driving them less would likely change the charicature of the sound. The important thing is not what you hear but what ends up on the tape(or disc), so I would not modify your amp. You will have to isolate the speakers into another room. I also would not use a Power Soak type device because if your tubes are already running flat out in Class A the last thing you want to do is lower the output impedence they see.
If you like the sound of a Class A amp but want less volume I would try to find another, less powerful, amp like an Epiphone Galaxy 10. These amps are very inexpensive here in the States, about the same price as a good distortion pedal. You should be able to use a 6V6 instead of the 6L6 with very little modification, if any. That would give you a 3 watt Class A amp that you could crank up all day long. They don't appear to be a current model because it looks like Epiphone has come out with a new line-up. You might be able to find one on a close out. Lot's of people have them and there is a lot of support on the web. Let us know if you find a way to make the Laney work for you.
John...........
 
Remove R49, then connect a guitar cord from the effects send back to the effects return. Now the effects level control will act as a master volume. SImple enough to try, and if it does what you want, great.

If you want power tube distortion, you will only get it when the power tubes are cranked. But if all you want is to get an overdrive sound from the preamp without getting loud out the speaker, this ought to work.
 
volume box on effects loop

I have a vc30 and it sounds much better as the volume is increased,i put a volume box,from e-bay $15.00 in the effects loop right before return jack,effects still can be used,and now it sounds much better,vol on 6 is moderate on low gain input and the tone is fabulous!

Before this it was too crispy brite too me,it really warms up with higher volume,no master vol amps luv high volume it seems!

I was taught class a/b is push/pull,[class A is not}the triodes are constantly on near %100 tube plate dissipation on a laney vc30,it is a true class A amplifier!

Dont pull your tubes,run all 4 el84,only amps that work this way have that info in operating instructions ,most times!
A attenuator option is about $75.00 on e-bay! not a perfect option as tone can suffer severely! it depends ! preamp tubes run class A also!!!