Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Erik Aa on January 20, 2023, 11:43:32 am

Title: Speaker issue with tube amp
Post by: Erik Aa on January 20, 2023, 11:43:32 am
I have a Traynor yba-1a bass amp that I recently switched all large electrolytic caps in, except the small ones for bias, etc. i plan to switch those too but they are difficult to find in the right values.

Here is my question. When I play the bass loud on a 600w 410 cab, I get a slight scratching sound from the speakers in certain frequencies at high volume. It is not tube overdrive distortion.  Can this issue be a result of the remaining old electrolytic caps? Or is it perhaps a preamp tube issue? Or simply blown speaker?

Any and all suggestions/help is much appreciated.

Thanks!
Title: Re: Speaker issue with tube amp
Post by: Platefire on January 20, 2023, 12:26:58 pm
First thing I would do is try another known good speaker cab that you could crank up to the same level and see if it does the same thing. If it does it's probable in the amp. If it doesn't with the different speaker, it was the speaker cab. So if you find it's wasn't the speaker cab, then it's time to check the amp out
Title: Re: Speaker issue with tube amp
Post by: Jennings on January 20, 2023, 01:19:56 pm
Definitely check the cab furniture out…sometimes screws, handles, loose speaker fixings, hanging wires, or even washers that have ended up lodging in/around the speakers, all can give rise to odd noises which sound like they might be the amp or speaker.
Title: Re: Speaker issue with tube amp
Post by: Erik Aa on January 21, 2023, 09:13:41 am
Thanks guys. I will perform some more tests.
Title: Re: Speaker issue with tube amp
Post by: mresistor on January 21, 2023, 12:01:32 pm
Also make sure the power tube sockets and preamp tube sockets pins are clean and tight. Sometimes the physical vibration of the bass signal at the cabinet can cause strange sounds from loose or dirty contacts.