The problem has been intermittent, with some transformers being affected, and others being ok. If you find that you have issues, please contact Primrose.
Measurements
I'm not trying to stir the pot. I simply wanted to offer some measurements that may inform other folks here. With the test rig noted in an earlier post, here is what I found:
I'm reporting the DC current through and voltage across the load at which I could hear the transformer buzz from a distance of approximately 1 meter (measured). The transformers were NOT mounted and simply rested on a large sheet of Baltic birch ply, supported off the floor by saw horses. There was a computer case fan running approximately the same distance behind me and it was audible. Point is, I heard transformer buzz above other background noises.
Methodology: I turned up the VAC on the primary side of the transformer with a VARIAC until I could hear the buzz from the Device Under Test (DUT). The output of the each DUT was connected to a rectifier/capacitor unit to create a +/- Vdc output. The output was then fed to the 'load' of 300W light bulbs. (Pictures previously posted)
Unit 1 (24+24, 800 VA, potted)
Idc = 2.14 A
Vdc = 7.5 V
Unit 2 (24+24, 800 VA, potted)
Idc = 2.08 A
Vdc = 6.6 V
Unit 3 (25 + 25, 400 VA, non-potted)
Idc = 2.77 A
Vdc = 15.4 V
Unit 4 (25 + 25, 400 VA, non-potted)
Idc = 2.8 A
Vdc = 15.9 V
Other notes... These are threshold values. As I increased above these state points, the buzzing increased. I didn't run the test long enough to feel a temperature rise in the transformers. I did place my hand on the them so I could feel the mechanical vibrations.
Comments/suggestions? I've e-mailed Primrose to get instructions on how to return these. I understand these things happen in manufacturing processes.
Ryan
I'm not trying to stir the pot. I simply wanted to offer some measurements that may inform other folks here. With the test rig noted in an earlier post, here is what I found:
I'm reporting the DC current through and voltage across the load at which I could hear the transformer buzz from a distance of approximately 1 meter (measured). The transformers were NOT mounted and simply rested on a large sheet of Baltic birch ply, supported off the floor by saw horses. There was a computer case fan running approximately the same distance behind me and it was audible. Point is, I heard transformer buzz above other background noises.
Methodology: I turned up the VAC on the primary side of the transformer with a VARIAC until I could hear the buzz from the Device Under Test (DUT). The output of the each DUT was connected to a rectifier/capacitor unit to create a +/- Vdc output. The output was then fed to the 'load' of 300W light bulbs. (Pictures previously posted)
Unit 1 (24+24, 800 VA, potted)
Idc = 2.14 A
Vdc = 7.5 V
Unit 2 (24+24, 800 VA, potted)
Idc = 2.08 A
Vdc = 6.6 V
Unit 3 (25 + 25, 400 VA, non-potted)
Idc = 2.77 A
Vdc = 15.4 V
Unit 4 (25 + 25, 400 VA, non-potted)
Idc = 2.8 A
Vdc = 15.9 V
Other notes... These are threshold values. As I increased above these state points, the buzzing increased. I didn't run the test long enough to feel a temperature rise in the transformers. I did place my hand on the them so I could feel the mechanical vibrations.
Comments/suggestions? I've e-mailed Primrose to get instructions on how to return these. I understand these things happen in manufacturing processes.
Ryan
Hi Ryan,
Thanks for take your time and send us your results.
I have two 600VA 24+24 in the drawer taking dust and I forgot to have them
Should be interesting to know what's the primerose reply.
I am in korea and I will not spent others money to ship them back but is really a pity.
Best Regards,
Enrico
Thanks for take your time and send us your results.
I have two 600VA 24+24 in the drawer taking dust and I forgot to have them
Should be interesting to know what's the primerose reply.
I am in korea and I will not spent others money to ship them back but is really a pity.
Best Regards,
Enrico
Sorry for resurrecting a really old thread.
I recently used the SumR toroids I got from this GB and they all buzz pretty loudly (I can easily hear them a few meters away). I tried using a DC blocker on the mains with no effect.
I also tried contacting Richard from SumR but he just blamed anything else in the power supply. After directing him to this thread asking if he found the cause and a solution, all I got was radio silence.
It seems that SumR doesn't stand behind their products anymore, even those from their Primrose line.
Lesson learn about spending any money on their transformers in the future, but I was wondering if there was any way to salvage these toroids? Has anyone had any success?
Thanks
Paul
I recently used the SumR toroids I got from this GB and they all buzz pretty loudly (I can easily hear them a few meters away). I tried using a DC blocker on the mains with no effect.
I also tried contacting Richard from SumR but he just blamed anything else in the power supply. After directing him to this thread asking if he found the cause and a solution, all I got was radio silence.
It seems that SumR doesn't stand behind their products anymore, even those from their Primrose line.
Lesson learn about spending any money on their transformers in the future, but I was wondering if there was any way to salvage these toroids? Has anyone had any success?
Thanks
Paul
2 of them are the potted version and 2 of them are non-potted. The potted versions buzz less loudly but still much above background noise. So it may be a solution for ones that only buzz slightly?
Unfortunately it doesn't seem like SumR wants to recognize that the problem has something to do with their fabrication, like some other toroids from the same GB. At least that's my interpretation from SumR's silence after my last email (which was a month ago).
Paul
Many of the SumR Toroids I bought in the past had loud buzz as well... Too bad because they're local company. I decided to buy a different brand that does not have any buzz.
Maybe the newer ones are better?
Maybe the newer ones are better?
I too had a buzzing in a transformer I purchased from Sum r I purchased direct from them and Richard did not want to resolve it. A shame I have not used the amp I built around it I was so disgusted.