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What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 5:22 am
by BrianFantana
It looks like it has "50" and "60" but I have no clue what this will do.
Can anyone clue me in?
Should I flip it?!?
Thanks!
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 8:00 am
by a.hun
Sounds like the mains voltage selector switch. Do not flip it!!!
The 50 / 60 Hz thing: Apart from different voltages (around 115 / 230V) US and European mains supplies have different AC (alternating current) frequencies, 50Hz in Europe, 60Hz in the US. The amp can run on either frequency but MUST be set to the correct voltage!
http://www.worldstandards.eu/electricit ... y-country/" onclick="window.open(this.href);return false;
Andy.
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 8:11 am
by Bensnake
Seems strange that they use a switch toggle (I assume you mean it's a toggle) for that... I've never seen one on any amp. Show us a pic!
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 11:24 am
by a.hun
Probably just the normal recessed slider switch, for 100V / 120V in the US. (Set to 120!)
Andy.
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 11:51 am
by BrianFantana
Thanks, gents!!!
(I wasn't going to switch it over w/o knowing.)
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 12:13 pm
by Jondog
They need to stop making those accessible.....
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 2:45 pm
by Thinline_slim
Jondog wrote:They need to stop making those accessible.....
Can you even simply switch if you're traveling overseas and want to use it? I think there's a lot more to it than that isn't there?
You know what would be handy... external bias sockets and trim pot for those amps that need biasing.
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 4:02 pm
by Bensnake
Thinline_slim wrote:You know what would be handy... external bias sockets and trim pot for those amps that need biasing.
+100
I owned a Rogue (canadian brand) hifi-amp with 4 Tung Sol KT-120's. It had a bias meter and trim pots on the top plate. A dream to handle though my current hifi-amp has auto bias and that's even better...
Re: What will the "VAC" switch on the back of my AD30 do?
Posted: Tue Sep 30, 2014 4:54 pm
by fiveightandten
Yes, it's a red slider, and it switches between 100V and 120V (for models shipped here to the states).
I bought my AD30 used. I ran it for quite some time without ever messing with it. I never needed to, as it worked flawlessly and sounded great. One day, I was in the chassis with a flashlight installing Velcro ties for the power cable. I had unplugged the speaker cable and looked up and noticed that little switch. I also noticed it was set to 100V!
Actually. It gets worse than that...the amp was also modded with 250 ohm cathode resistors. Presumably, someone had it on the wrong voltage setting, and since the EL84s were running super hot, they changed the cathode resistors out to calm things down.
God knows how long it was running like this. It was putting 460V on the plates. IIRC. Heaters were seeing close to 7VAC. The amp sounded great. Dare I say I liked the sound a little better then when I brought it back to stock.
But the EL84s were running at like 18W each, IIRC. It's curious they lasted so long like that. They never red plated or protested in any way.
Anyways, long story short, keep the switch in the proper position.
-Nick