I got the new power transformer installed yesterday and seem to bet getting some weird buzzing from the pt. It is loud, but the transformer does not get warm or hot AND it only happens once the tubes warm-up,Mohicans implies (to me) a HV issue rather than heater.
It is the Hammond 374bx and has more than enough power for a basic SSE running KT88's with rk of 560k.
Here are details:
1. CL-90 on line to primary at IEC
2. 1N4007 on HV secondaries
3. CL-140 on HV center-tap.
When I followed Ty's checkout, I only got 190 vac at the HV into the tube rectifier. I assume this is because of the 1N4007's. Is this correct?
My optional power supply cap is glued under the chassis directly below the pt, could the cap (clarity cap) be causing interference?
I'd love some ideas?
Thanks,
Charlie
It is the Hammond 374bx and has more than enough power for a basic SSE running KT88's with rk of 560k.
Here are details:
1. CL-90 on line to primary at IEC
2. 1N4007 on HV secondaries
3. CL-140 on HV center-tap.
When I followed Ty's checkout, I only got 190 vac at the HV into the tube rectifier. I assume this is because of the 1N4007's. Is this correct?
My optional power supply cap is glued under the chassis directly below the pt, could the cap (clarity cap) be causing interference?
I'd love some ideas?
Thanks,
Charlie
When I push on one side of the end bells, towards the middle edge of the transformer, the buzz subsides. When I tightened the bolts, the buzzing got worse, so I reduced the tightness of the bolts.
I specifically avoided removing the end bells for painting as the Hammond tech guy said that it would void the warranty.
It is very frustrating as I purposely didn't follow up on my Edcor warranty because of their 6-8 week wait time from ordering. Other Hammond transformers on my Aikido preamp are nowhere near as buzzy.
Could I have wired the 1N4007's incorrectly? I wired them with the cathode end towards the disconnects of the board, as my board is one of the older ones. Of course, they're covered with heat shrink which I could remove. What if one had failed, but not the other.
Charlie
I specifically avoided removing the end bells for painting as the Hammond tech guy said that it would void the warranty.
It is very frustrating as I purposely didn't follow up on my Edcor warranty because of their 6-8 week wait time from ordering. Other Hammond transformers on my Aikido preamp are nowhere near as buzzy.
Could I have wired the 1N4007's incorrectly? I wired them with the cathode end towards the disconnects of the board, as my board is one of the older ones. Of course, they're covered with heat shrink which I could remove. What if one had failed, but not the other.
Charlie
Ahhh, I use NOS rectifiers since I popped my JJ 5AR4 and arc'd over my Groove Tube 5U4 (which still works).
I grabbed my Japanese 5AR4 last year for $50, I also keep my eyes open for more of them.
Look for ones with the seam on the top of the glass.
It is very nice.
You said you could push on the bolt and the buzz would get quieter?
But when you tightened the bolts the buzzing got louder.
Maybe your finger was dampening the ringing?
Try to go to the hardware store and get a couple neoprene washers.
Put one on either side of the transformer against the endbell.
Maybe that will damp the buzzing without overtightening the bolts???
I grabbed my Japanese 5AR4 last year for $50, I also keep my eyes open for more of them.
Look for ones with the seam on the top of the glass.
It is very nice.
You said you could push on the bolt and the buzz would get quieter?
But when you tightened the bolts the buzzing got louder.
Maybe your finger was dampening the ringing?
Try to go to the hardware store and get a couple neoprene washers.
Put one on either side of the transformer against the endbell.
Maybe that will damp the buzzing without overtightening the bolts???
Also try oversizing the mounting holes on the chassis lid and installing rubber grommets in the metal.
Then use a nut with washer on the underside.
That will decrease the amount of vibration that is transmitted to the chassis top.
The same trick is used with mechanical hard drives in computers to great success.
Then use a nut with washer on the underside.
That will decrease the amount of vibration that is transmitted to the chassis top.
The same trick is used with mechanical hard drives in computers to great success.
Well, I moved the SSE to my listening room and connected it to my Aikido-pre and Polk floorstanders. The buzzing has gone! The SSE is being fed through my Belkin PureAV surge/conditioner.
A number of possibilities occur to me:
1. SSE has cooled down, so start-up while warmish could be having an effect - EI core saturation issues?
2. Filtered AC to the SSE?
3. Maybe the unused taps,etc on the pt (ends sealed with heat shrink and then coiled) have shifted into a more beneficial position?
As to the sound - great. I am running a 12au7 as the input tube as it has a lower amplification factor. It is getting 10mA as per George's specification for the ccs, when it seems that 20mA would be better.
With the 12at7, sound was far more robust - of course, but there also seemed to be a bit more bass, although it was a little on the boomy side.
Either way, it's good.
Charlie
A number of possibilities occur to me:
1. SSE has cooled down, so start-up while warmish could be having an effect - EI core saturation issues?
2. Filtered AC to the SSE?
3. Maybe the unused taps,etc on the pt (ends sealed with heat shrink and then coiled) have shifted into a more beneficial position?
As to the sound - great. I am running a 12au7 as the input tube as it has a lower amplification factor. It is getting 10mA as per George's specification for the ccs, when it seems that 20mA would be better.
With the 12at7, sound was far more robust - of course, but there also seemed to be a bit more bass, although it was a little on the boomy side.
Either way, it's good.
Charlie
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