slave amp question

[dslman]

I'm coming out of my stereo effects pedals --one going to my fx return on my 100 watt Marshall and the other stereo out " same pedal"to a slave amp fx return 50 watt amp. This gives me a huge stereo sound that I love. This set up bypasses any of the controls on the slave amp and the volume is mostly controlled by the Marshall. My question is : Will a 20watt tube head work the same ? and will it be enough wattage ? I'm thinking the slave amp is basically just putting a load on the speakers and the main power and sound comes from the Marshall. Right now I'm using a combo amp for the slave ,but don't want to lug that thing around.
Sorry if I should have put this in the Tone Zone thread.
Thanks for any advise.

 

[dslman]

Ok guys , I know it's a tough question,or two. The questions is primarily about the wattage of the slave amp. Will a 20 watt tube head be enough wattage when used as a slave amp and only running through its fx loop and to put a load on the cabinet it is hooked to.My 100w Marshall is the master amp.

 

[Micky]

Lets get this straight - from stereo pedal to 2 amps fx return... correct?
Bypassing both amp premp sections?

How do you control the volume? Guitar?

 

[dslman]

That's correct on the set up, "since it's just my time based effects". The volume is controlled by the master amp ie.. the Marshall 100w.

 

[dslman]

If I increase vol on the master head , it also goes up on the slave. I'm hoping a little 20w tube head will be enough to do the job as a slave as long as the impeadance is correct. I've had good success so far w/ a dsl,b-52 ,and a cheap 50w combo amp all used as slaves. I would rather use a small head and just run it as a slave through one side of a stereo cabinet.

 

[Brett Blackmore]

If I increase vol on the master head , it also goes up on the slave. I'm hoping a little 20w tube head will be enough to do the job as a slave as long as the impeadance is correct. I've had good success so far w/ a dsl,b-52 ,and a cheap 50w combo amp all used as slaves. I would rather use a small head and just run it as a slave through one side of a stereo cabinet.

Hi,

you must be carefull with the volume from the master - if I understand this right you are using the Marshall for send & return with one channel of your fx device but also using the other channel to return to the slave - bypassing its pre-amp stage - right? If you have the volume/impedance too high then you can damage the smaller slave amp. I used this setup in the past but always had the amps approx. equal. In fact I tried an ENGL amp once as a slave and it allowed me to control it's volume at th efront even though I was coming in via the fx-loop return at th eback - clever them Germans...

Cheers Brett

 

[dslman]

Hi,

you must be carefull with the volume from the master - if I understand this right you are using the Marshall for send & return with one channel of your fx device but also using the other channel to return to the slave - bypassing its pre-amp stage - right? If you have the volume/impedance too high then you can damage the smaller slave amp. I used this setup in the past but always had the amps approx. equal. In fact I tried an ENGL amp once as a slave and it allowed me to control it's volume at th efront even though I was coming in via the fx-loop return at th eback - clever them Germans...

Cheers Brett

Yes Brett, you have understood everything I was trying to convey. I also use to do this w/ two DSL's and had the same experience with being able to control the vol on the slave, in fact it seems to work the same on two other amps I tried as slaves, but only the vol. on the slave amp is usable. Once I set the slave amp vol. to match the master amp I then leave it alone since the master amp vol. also effects the slave and all is equal. If I lower or raise the master controls, it effects the slave as if they were one.
Seems you understand this scenario since you have also used it.
I generally don't get my 100W Marshall over 3 or 4 on the master, so I'm thinking a 20w tube head should work well as a slave.
The impedance would be the same,each head 8 ohms and pushing a 2x12 each.
I was hoping someone on this forum would know how the two amps actually effect each other when the loops are the only things connected , and one head being a 100w and the 2nd a 20w.
Maybe the proper term is not "slave" in the technical sense.
Thanks Brett for the reply.

 

[Frodebro]

Both power sections are receiving a line level signal from the big amps preamp, it's just split to stereo at the pedals. As long as both amps have the correct impedance speakers connected to them, nothing will get hurt this way.

A preamp outputs roughly the same signal level regardless of the size of the power amp it's driving, so a preamp in a 100W amp is going to output the same signal as the preamp in a one watt amp.

 

[dslman]

Both power sections are receiving a line level signal from the big amps preamp, it's just split to stereo at the pedals. As long as both amps have the correct impedance speakers connected to them, nothing will get hurt this way.

A preamp outputs roughly the same signal level regardless of the size of the power amp it's driving, so a preamp in a 100W amp is going to output the same signal as the preamp in a one watt amp.

Awesome ! That's what I was thinking and hoping. Thanks Frodebro .

 

[dslman]

I've never actually ran a 20w tube head into a 4x12 , but I've heard they can hold their own pretty well volume wise.

 

[mickeydg5]

A 20 watt amplifier is not going to match a 100 watt if it is maxed.
If the 100 watt is not maxed, turned down, and the 20 watt can be turned up then you can get similar or the same volume out.
The 20 watt will have more overdrive/saturation while the 100 watt will have more headroom in that case.

 

[dslman]

A 20 watt amplifier is not going to match a 100 watt if it is maxed.
If the 100 watt is not maxed, turned down, and the 20 watt can be turned up then you can get similar or the same volume out.
The 20 watt will have more overdrive/saturation while the 100 watt will have more headroom in that case.

In this scenario I will be bypassing the preamp section of the 20w and using fairly low volume on the 100w comparatively. I'll probably have to push the 20w ,but hopefully I can still have some decent CLEAN power out of it. The two main reasons I am going for this set up is for the stereo sound and the portability of a 20w lunchbox. Oh yeah #3, a good backup. lol. Lugging two DSL's around got old pretty fast. I guess I'm old to.

 

[Frodebro]

In this scenario I will be bypassing the preamp section of the 20w and using fairly low volume on the 100w comparatively. I'll probably have to push the 20w ,but hopefully I can still have some decent CLEAN power out of it. The two main reasons I am going for this set up is for the stereo sound and the portability of a 20w lunchbox. Oh yeah #3, a good backup. lol. Lugging two DSL's around got old pretty fast. I guess I'm old to.

The preamp from the big amp is going to be controlling the volume for both amps, as the volume controls are part of the preamp.

Power amps run at 100% power, the signal from the preamp is what determines how much output you get based on the strength of the input signal hitting the power amp. So turning down the master volume on the big amp will reduce the signal hitting the effects send, which in turn reduces the signal to both power amps.

The easiest workaround here is to run lower efficiency speakers off of the bigger amp, and use fewer of them with the big amp (if either option is possible).

 

[Ugly Duckling]

The preamp from the big amp is going to be controlling the volume for both amps, as the volume controls are part of the preamp.

Power amps run at 100% power, the signal from the preamp is what determines how much output you get based on the strength of the input signal hitting the power amp. So turning down the master volume on the big amp will reduce the signal hitting the effects send, which in turn reduces the signal to both power amps.

The easiest workaround here is to run lower efficiency speakers off of the bigger amp, and use fewer of them with the big amp (if either option is possible).

Say what?
Doesn't the effect loop come before the master volume?
Like this: Preamp -> effects loop -> Master volume -> Power amp -> speakers?

 

[Micky]

That is what I thought.
How to control the volume?
OP was not clear at all...

 

[Frodebro]

Say what?
Doesn't the effect loop come before the master volume?
Like this: Preamp -> effects loop -> Master volume -> Power amp -> speakers?

I guess it depends on the amp, so that is something worth checking.

 

[dslman]

That is what I thought.
How to control the volume?
OP was not clear at all...

Well I was as clear as I could be , I thought. I answered by saying I control volume with the master amp.
Frodebro has answered my questions pretty well .He is correct in saying that the volume on the master amp controls the volume on both amps when connected this way. Since the slave only sees what is coming from the master loop and it's volume is effected as the master is manipulated.
What is so cool about this setup is the fact that you don't use any controls on the slave and all the Marshall preamp and tone controls are what is heard. It's a great way to achieve a big stereo sound.

 

[mickeydg5]

I think what is meant is that it would help to know which amplifiers are being used in this situation. Most amplifiers do not operate the same or may have their volume/level controls in various points of the signal chain.

Frodebro is guessing unless he knows the situation personally. No one else wanted to guess or make assumptions.

 

[dslman]

That's cool,I appreciate any help, I use a 2203x and was considering the Peavey Valveking Micro 20. I know they should both be serial loops to get along. After lots of thought , I will prob. go w/ a 50w Laney lh50 to make sure the power is there.

 

[Frodebro]

Well I was as clear as I could be , I thought. I answered by saying I control volume with the master amp.
Frodebro has answered my questions pretty well .He is correct in saying that the volume on the master amp controls the volume on both amps when connected this way. Since the slave only sees what is coming from the master loop and it's volume is effected as the master is manipulated.
What is so cool about this setup is the fact that you don't use any controls on the slave and all the Marshall preamp and tone controls are what is heard. It's a great way to achieve a big stereo sound.

If the master volume controls the volume of both amps, the MV is before the loop in the circuit.