Post by Monarchy Audio on Sept 18, 2012 11:31:38 GMT -5
Kevin F., UK:
Dear Mr Poon,
I am writing to thank you for the delivery of my SM70 amplifiers. To say I am delighted with sound would simply be an understatement. I am using them in fully balanced mode with the XLR connection. The weight, scale and dynamics of the music is astounding. I will not be changing them. In fact I am already considering purchasing a second pair to bi amp the speakers. (Eminent LFT 16). That said I do have a concern. As I write I am listening to them and all is well. However tonight one amplifier has blown the 3 amp fuse (accessible on the rear panel) on three occassions. Fortunately I happened to have suitable replacements. The first time it went was when I switched on the amplifier. I should say now that this was done mistakenly with the XLR lead disconnected at the pre amp end. The other amp did not blow the fuse. Upon realising my mistake I turned both amps off and reconnected the XLR leads. Hopefully turning them on again I found the fuse had gone on one amp. I replaced the fuse and tried the amp again having first checked all leads, mains and interconnects for shorts and found no problem. There were no shorts on the outputs and no problems with speakers that I could tell. I turned on the pre amp first (as you say is best) The fuse went again without the light comming on. Replacing the fuse again I switched the amp on without the pre amp on. The fuse went again. I put the last 3 amp fuse I had and turned the amp on with no other equipment on. The amp has stayed on and is working as I write. I am hoping you may have an explanation and a way I can prevent it happening again. All the components are run from a mains conditioner. This is an Isol- 8 Cleanline 2 unit with 6 dedicated outlets.
A second question I have is about hum. Both amps hum, one is obviously louder than the other (the quiet one is the one that has blown the fuses) The amps can be heard clearly from the listening position about 5 yards away. I use dedicated mains cables from Chord and Russ Andrews. Swapping these around and then using another cable that is sheilded ( the braiding is connected at the plug earth end only), I hear no difference in the hum on either amp. Should I hear any hum from the amps? There is no hum through the speakers, just a low level phasey swishing sound that does not vary much with volume and can only be heard when right up to the cone. I have read in one of the amp reviews that disconnecting the earth at the plug can reduce earth related hum issues. I have not tried this and am a little reluctant to do so as I believe the amps are designed to have an earth connected. I had not had hum on the previous amp. The toggle switch is in the down postion and the speakers are wired between the two red terminals as instructed for balanced operation. As I have said I could not be more pleased with sound, I just fear that when I come to switch on the amp again the fuse will go. It would be good to get rid of the hum, it is noticable over quiet passages of music.
Very Best Regards,
Kevin
Another comment:
Hello Mr Poon,
I am still very much enjoying the amps, they really are very special. I have had no problems with the fuse blowing and will stick with the 4 amp T rated fuses I have put in both. As for the hum you are right it does subside a little as they warm. I am hearing past that now, as I am tending to listen a little louder as the amps encourage that, being so clean. I shall as I said, save up and purchase another pair for bi amp use. For over 30 years now I have enjoyed music and Hi Fi. Not always in that order! I really don't remember all the equipment I have had, but undoubtedly these are the best and the last amps I will purchase.
Many Thanks
Kevin.
Dear Mr Poon,
I am writing to thank you for the delivery of my SM70 amplifiers. To say I am delighted with sound would simply be an understatement. I am using them in fully balanced mode with the XLR connection. The weight, scale and dynamics of the music is astounding. I will not be changing them. In fact I am already considering purchasing a second pair to bi amp the speakers. (Eminent LFT 16). That said I do have a concern. As I write I am listening to them and all is well. However tonight one amplifier has blown the 3 amp fuse (accessible on the rear panel) on three occassions. Fortunately I happened to have suitable replacements. The first time it went was when I switched on the amplifier. I should say now that this was done mistakenly with the XLR lead disconnected at the pre amp end. The other amp did not blow the fuse. Upon realising my mistake I turned both amps off and reconnected the XLR leads. Hopefully turning them on again I found the fuse had gone on one amp. I replaced the fuse and tried the amp again having first checked all leads, mains and interconnects for shorts and found no problem. There were no shorts on the outputs and no problems with speakers that I could tell. I turned on the pre amp first (as you say is best) The fuse went again without the light comming on. Replacing the fuse again I switched the amp on without the pre amp on. The fuse went again. I put the last 3 amp fuse I had and turned the amp on with no other equipment on. The amp has stayed on and is working as I write. I am hoping you may have an explanation and a way I can prevent it happening again. All the components are run from a mains conditioner. This is an Isol- 8 Cleanline 2 unit with 6 dedicated outlets.
A second question I have is about hum. Both amps hum, one is obviously louder than the other (the quiet one is the one that has blown the fuses) The amps can be heard clearly from the listening position about 5 yards away. I use dedicated mains cables from Chord and Russ Andrews. Swapping these around and then using another cable that is sheilded ( the braiding is connected at the plug earth end only), I hear no difference in the hum on either amp. Should I hear any hum from the amps? There is no hum through the speakers, just a low level phasey swishing sound that does not vary much with volume and can only be heard when right up to the cone. I have read in one of the amp reviews that disconnecting the earth at the plug can reduce earth related hum issues. I have not tried this and am a little reluctant to do so as I believe the amps are designed to have an earth connected. I had not had hum on the previous amp. The toggle switch is in the down postion and the speakers are wired between the two red terminals as instructed for balanced operation. As I have said I could not be more pleased with sound, I just fear that when I come to switch on the amp again the fuse will go. It would be good to get rid of the hum, it is noticable over quiet passages of music.
Very Best Regards,
Kevin
Another comment:
Hello Mr Poon,
I am still very much enjoying the amps, they really are very special. I have had no problems with the fuse blowing and will stick with the 4 amp T rated fuses I have put in both. As for the hum you are right it does subside a little as they warm. I am hearing past that now, as I am tending to listen a little louder as the amps encourage that, being so clean. I shall as I said, save up and purchase another pair for bi amp use. For over 30 years now I have enjoyed music and Hi Fi. Not always in that order! I really don't remember all the equipment I have had, but undoubtedly these are the best and the last amps I will purchase.
Many Thanks
Kevin.
