Peaman

Amp damage

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Evening guys

I picked up my Dads old Wharfdale Lintons this afternoon, that he built 45 years ago.  

Eager to get them up and running tonight, I hooked them up to my Trafomatic 300b integrated valve amp, which has been in storage for a while.

Because the speakers are an old kit build, the terminals are just a couple of screws in the back. So, I dug out some bell wire, and hooked them up. 

In my rush, I had wired the speaker wire incorrectly at the amp end with +ve to the 8ohm tap, and negative to the 16ohm tap rather than to the negative terminal on the LHS channel.

There was no sound coming from that channel, which led me to my mistake.

I've rectified the issue, but still no sound coming out. I've checked the same speaker on the other channel and it the speaker works, so would appear that the speaker is alive and well. 

My question is, would hooking up the speaker to both the 8ohm and 16 ohm taps fry the amp on that channel?

All tubes appear fine, all uniform no crackles etc.....

One of those , should have waited until tomorrow when your fresh jobs. When will I learn.......

Cheers guys

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Super Wammer
16 minutes ago, Peaman said:

Evening guys

I picked up my Dads old Wharfdale Lintons this afternoon, that he built 45 years ago.  

Eager to get them up and running tonight, I hooked them up to my Trafomatic 300b integrated valve amp, which has been in storage for a while.

Because the speakers are an old kit build, the terminals are just a couple of screws in the back. So, I dug out some bell wire, and hooked them up. 

In my rush, I had wired the speaker wire incorrectly at the amp end with +ve to the 8ohm tap, and negative to the 16ohm tap rather than to the negative terminal on the LHS channel.

There was no sound coming from that channel, which led me to my mistake.

I've rectified the issue, but still no sound coming out. I've checked the same speaker on the other channel and it the speaker works, so would appear that the speaker is alive and well. 

My question is, would hooking up the speaker to both the 8ohm and 16 ohm taps fry the amp on that channel?

All tubes appear fine, all uniform no crackles etc.....

One of those , should have waited until tomorrow when your fresh jobs. When will I learn.......

Cheers guys

Shouldn't have. It depends on how the output transformer's  wired, but as it's only got two taps, I'm assuming the secondary is tapped, rather than having several secondaries wired in series, so  electrically, going between 16 ohms and 8 is the same  as going between 8 ohm and ground. Some difference as to where any feedback is taken from, but essentially the same. 

You should never run a valve amplifier without a load attached, even with nothing playing, as that can cause serious damage to the output transformer.

S

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The speakers were hooked up at all times, but it was just that LHS channel that I messed up on. 3 outputs out back per channel  8/16/Ground and I wired 8/16 no ground. 

Thanks as always Serge..

Just dusting down some kit after standing back from Hifi for a while. Can't get the brain in gear....

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Super Wammer

I'm with Serge in thinking what you did should not have caused damage. In fact I have done similar in a brain fade moment with no damage. It might be something else causing no sound. Best take a step back and work through things logically, swopping channels, wires and valves over to eliminate stuff.

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I think your right, I'll do just that and work through . 

It's typical, as I've just cleared out and Ebayed a load of spare valves, including a pair of 300b's - Sods law right!

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