Home » Audio » Pro Sound » Yet another (but more specific) impedance question
Yet another (but more specific) impedance question [message #27392] Wed, 21 February 2007 09:34 Go to next message
kittykat is currently offline  kittykat
Messages: 1
Registered: May 2009
Esquire
Hi friends,

I know impedance questions are soooo common, but I have one that I haven't really been able to find an answer to.

First, some context. I'm looking at buying a Marshall DSL 100 because the tone makes me drool (it works for my purposes) and it can be real loud when it needs to be.

This will be my first all tube amp, so I'm still getting my head around the specifics of tube sound/power, etc.

But my question is about volume and impedance. I noticed that, like some other amps that I've tried, the beautiful tone that I love only really kicks in once you push the amp past a certain level of volume. That's gonna be fine for certain applications, but for practices I might need to be quieter. I would like be able to maintain that tone in those situations but have my head/cab be a bit quieter. Setting the volume at, say, 1 or 2 does not sound good on the head.

Now, I know some amps have a 1/4 switch on the back that cuts the volume down somehow, but the DSL100 doesn't. What it does have, however, is an impedance selector that allows you to tell the amp whether its being hooked up to a 4, 8, or 16 ohm cab.

The manual says that if you're running a single 4 ohm cab or two 8 ohm cabs, then you should set the switch to 4 ohms; and if you are running a single 8 ohhm cab or two 16 ohm cabs, you should set it to 8 ohms. Fine. I get the logic of matching things up like that.

What I'm wondering is if I can achieve a similar "quietening" effect to a 1/4 switch (or 1/2 switch or whatever) by purposefully running an 8 ohm cab from head set to 4 ohms. Would this cut the loudness of the setup in, approximately, half? Would it be noticeably quieter but with a similar tone? Would I simply need to drive the head a bit more to get a similar volume as I would if I were using a 4 ohm cab?

And would it affect the tone at all?

And would it be "bad" for the head at all?

I can clarify if need be -- I only have a basic understanding of this stuff at best.

FYI, I don't have the option of buying an additional practice amp. And I know the DSL 50 exists.

best,

dave



Re: Yet another (but more specific) impedance question [message #27393 is a reply to message #27392] Wed, 21 February 2007 10:07 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18671
Registered: January 2001
Illuminati (33rd Degree)

If you like the sound of the amp when it's pushed hard, I suppose you could pad the output down. Use an L-Pad on the output, between the amp and speaker.


Re: Yet another (but more specific) impedance question [message #27403 is a reply to message #27393] Tue, 10 April 2007 09:37 Go to previous messageGo to next message
Chris R is currently offline  Chris R
Messages: 133
Registered: May 2009
Master
Hi Wayne,
Didn't realize you hung out here so much. Anyway, about padding power,
Marshall makes (or used to make) a PowerBrake specifically for this.
http://www.schematicheaven.com/marshallamps/powerbrake.pdf
I think there were a couple of other similar dodads (Tom Sholze PowerSoak, etc.).
Chris

Re: Yet another (but more specific) impedance question [message #27404 is a reply to message #27403] Tue, 10 April 2007 21:46 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18671
Registered: January 2001
Illuminati (33rd Degree)

I usually don't have time to do much more than check on the π Speakers forum, maybe look in on the High Efficiency Speakers forum occasionally. But when I have a chance, I check on the other ART forums too. If there is something I can contribute - particularly if someone has written a post to which there is no reply - I'll try to offer something useful. But my time has become very thin these days.


Re: Yet another (but more specific) impedance question [message #27547 is a reply to message #27392] Thu, 31 January 2008 18:51 Go to previous message
Hayden Hallgren is currently offline  Hayden Hallgren
Messages: 2
Registered: May 2009
Esquire
Setting the wrong impedance can damage the output transformer in the amp, it starts working too hard and gets damaged. the best option is to get a power-break or some sort of power attenuator, but those are probably about as expensive as the amp itself.

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