# Traynor YBA-1 very noticeable hum from amp head (but not through cab)



## iblastoff (May 14, 2011)

Just picked up a used Traynor YBA-1 head. Its a 1970+ version (pretty sure theres no tube rectifier in it)

Brought it home and plugged in...everything seems to work and sound just fine except theres a very noticeable hum coming from the amp head itself (but not through my 8 ohm cab). The hum is there even on standby mode.

I tried switching the ground switch in the up and down position with no change. The hum is completely independent of anything else (turning volume up doesn't change the hum at all). 

Also, when I put my hand on top of the amp and then turn it on, there seems to be a noticeable vibration when it powers on. Like a feint but sudden shudder/shake. This only happens when its initially flipped on.

Other than that, regular amp noise coming through the speakers is actually quite minimal even when dimed.

I have no idea if its been modded or not but it does have a 3 prong power cord. Of course I'm not expecting a full diagnosis through a forum post but just wondering if anyone had any ideas or similar experiences on how to fix/get rid of the hum!

Thanks!


----------



## dtsaudio (Apr 15, 2009)

If I understand you correctly, it's a physical hum from the head. What your hearing is the power transformer vibrating. All transformers buzz to some extent, some get really noisy. It may just be age and the core laminations are vibrating more than usual. Other than replacement there's nothing you can do. However the more current drawn the more the transformer will vibrate. It's possible there is something wrong and the amp is drawing too much current somewhere. If the transformer is too hot to touch you have an issue. If it's only warm, probably no problem.
That sudden increase in vibration at turn on is called inrush current. Caused by the power supply capacitors charging up. Nothing to worry about there.


----------



## Greenbacker (Mar 29, 2007)

Mine does the exact same thing! No noise through the speakers, sounds great, but definitely a physical operating hum. Mine's a little earlier than yours and it's almost completely stock (including tubes) so I'm going to hold off until I can find the right tech to look at it to ensure I'm not causing the amp any harm. (Any volunteers/recommendations?!) There's some old components in these things afterall.


----------



## Scottone (Feb 10, 2006)

I've found that many of the older Traynors have this issue. You can try tightening up the bolts that hold the tranformer in place as this sometimes helps.


----------



## iblastoff (May 14, 2011)

dtsaudio said:


> If I understand you correctly, it's a physical hum from the head. What your hearing is the power transformer vibrating. All transformers buzz to some extent, some get really noisy. It may just be age and the core laminations are vibrating more than usual. Other than replacement there's nothing you can do. However the more current drawn the more the transformer will vibrate. It's possible there is something wrong and the amp is drawing too much current somewhere. If the transformer is too hot to touch you have an issue. If it's only warm, probably no problem.
> That sudden increase in vibration at turn on is called inrush current. Caused by the power supply capacitors charging up. Nothing to worry about there.


yah it seems like its definitely a physical hum from the head. i mean some of my other amps exhibit similar hum coming only from the head but this is way louder. this is my first 'vintage' amp so i'm not really used to the relatively loud hum. i've brought it into a local tech to take a look at. hopefully its not a big deal and i don't have to replace the transformer or anything. thanks.


----------



## ed2000 (Feb 16, 2007)

I'll chime in here..my 66 YBA 1 transformer hums as well..probably forgot the lyrics.


----------

