Have I annoyed my amplifier . . .

[Opti-cal]

Hi Sounders,

I recently had the urge to try some Western Electric 16awg wire (old red/black stuff) which was highly recommended to try with my Quad ESL 57's.

Anyway, I hooked everything up and used just a bare wire to terminal connection for purity of signal as per recommendation.

Pressed play, turned up the volume but only the left channel had sound. Realised the wire was not in good contact with the right channel after a few seconds and all seemed okay.

I swapped back in my old speaker cable with proper connectors straight away but since this misdemeanor there is definitely something missing from the sound.

On tracks I know particularly well the extension of highs and lows is not there and the sound seems compressed and it seems like I have to crank the volume a tad more also.

The amplifier is a low power SET (not absolutely ideal for ESL's I know but the negative feedback from the amp seems to make them sound very nice in my small listening environment).

I'm aware of the dangers of not having speakers hooked up while playing through a tube amp but it was barely 5 seconds maybe 10 . . .

It's not a massive issue if the damage is done as the amplifier is not my most expensive one thank goodness but I just wondered if anyone could suggest what it has done to it. Eg: damaged the output tubes/transformers/caps/rectifier ALL OF THE ABOVE!?!?!

I will have a play about this week when I have some time to see if swapping the output tubes/rectifier makes any difference.

I've had instances of amplifiers "coming back" after voltage surges/sudden disconnections and after a few days they seem alright again, I have also had amplifiers go pop after seemingly having very little wrong with them. This seems somewhere in between.

Seems strange as I would not expect just a small deterioration in sound if there was an issue I would have expected either no sound at all or very bad sound.

All help and advice much appreciated!

Cheers,

Chris

[Macca]

Sounds like you might have done some damage to it - worth getting it to an engineer and having them check it out. It is possible that something has gone off spec and caused a deterioration rather than a complete failure, it can and does happen.

[Ali Tait]

What output valves does it use?

If they are triodes or pentodes run in triode mode no damage will result from running it not connected to the speakers.

[Opti-cal]

Thanks for replies so far guys.

It currently uses some Psvane 6CA7 T-II's in triode mode.

Is it still possible that there is damage to the other parts of the amp eg: transformers or caps? Or does the fact its operating in triode mode mean there cannot be damage to any other components?

I will certainly get it checked out as something is different.

I can swap out all the tubes for different ones and also test these tubes in another amplifier to hopefully get to the route cause. I guess if the issue is still there with all different tubes the issue is inside the amplifier.

It's pretty simple inside so hopefully not too much of a headache . . .

Thanks.

[Ali Tait]

Shouldn’t have caused any damage given the valves are run in triode mode and the short time you didn’t have speakers connected shouldn’t have caused an issue even so. Good idea to try different valves first, if that doesn’t solve it then as Macca says have it checked out.

[anthonyTD]

Worst case is you've damaged the output transformer, but as others have said' this is unlikely if you were not driving the amp very hard and for only a short amount of time etc.
Hope you get it sorted.
A...

[Opti-cal]

Just a little update if anyone is interested!

Had a swap around of tubes starting with outputs then rectifier. Both changes seemed to yield improvement so I stuck the original tubes that were installed when the issue occurred in a similar amp to see if they were the culprit. To my surprise everything sounded fine so just to prove I wasn't hearing things (or not) I put the tubes back into the first amp and had a listen.

Everything is back to normal, the missing extension and timbre of notes is back and music is hanging in mid air in front of me again. No rhyme or reason behind it at all!

It was almost like the amp needed to clear its throat and have some different tubes in it to re bias.

Obviously that sounds bizarre and probably isn't possible but the main thing is my hifi is back!

More likely a loose/poor connection somewhere that I have inadvertently rectified but I'm just happy its back.

Very frustrating not knowing exactly why or how though!


Thanks for the comments and advice - much appreciated.

[Ali Tait]

Could’ve been dirty pins/ sockets, changing the valves fixed it.