Gain difference between output impedance on Rocket

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paulster
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Re: Gain difference between output impedance on Rocket

Post by paulster »

showsii wrote:I happen to like 16ohm going into an 8ohm cab.. Now, is this going to screw up something?
This means that the tubes will be seeing half the impedance load that they otherwise would, so current draw will be increased but you won't run the risk of generating flyback voltages enough to cause flashover, which can be a concern if you mismatch the other way.

It'll work your power tubes harder (and they're worked pretty hard already in the AC30 output stage) but then Ken did specify a relatively high output impedance anyway, so it's not all bad.

In a nutshell it'll be fine but your tubes won't last as long.
Cliff Schecht
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Re: Gain difference between output impedance on Rocket

Post by Cliff Schecht »

Learn your amps! I've put enough time and thought into my builds that I usually remember the goofy stuff no problem. Even if I forget initially, it's usually obvious when the volume is overtly low or the amp just sounds off. I use 8 Ohms on just about everything anyways so my stuff is usually set as it needs to be already.
Cliff Schecht - Circuit P.I.
showsii
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Joined: Wed Feb 09, 2011 9:12 pm

Re: Gain difference between output impedance on Rocket

Post by showsii »

paulster wrote:
showsii wrote:I happen to like 16ohm going into an 8ohm cab.. Now, is this going to screw up something?
This means that the tubes will be seeing half the impedance load that they otherwise would, so current draw will be increased but you won't run the risk of generating flyback voltages enough to cause flashover, which can be a concern if you mismatch the other way.

It'll work your power tubes harder (and they're worked pretty hard already in the AC30 output stage) but then Ken did specify a relatively high output impedance anyway, so it's not all bad.

In a nutshell it'll be fine but your tubes won't last as long.

Got it! Thanks for the explanation. Mismatched the way I stated and evenly matched at 8 ohms both sound great, so we will see what kind of mood I'm in on any given day to set the impedance.

Ian
showsii
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Re: Gain difference between output impedance on Rocket

Post by showsii »

Cliff Schecht wrote:Learn your amps! I've put enough time and thought into my builds that I usually remember the goofy stuff no problem. Even if I forget initially, it's usually obvious when the volume is overtly low or the amp just sounds off. I use 8 Ohms on just about everything anyways so my stuff is usually set as it needs to be already.

+1, that's a good word

Ian
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overtone
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Re: Gain difference between output impedance on Rocket

Post by overtone »

Ian, from your first post I was assuming that you were connecting 16 to 16 or 8 to 8.
+1 to what Paulster wrote.

I have given up on tap selector switches and fit sockets wired as parallel pairs for each impedance. That gives me more flexibility for the cabs that I have, but the potential draw back is that I cannot use a switched ground on the speaker out.
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