optical
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Post by optical on Aug 19, 2021 10:28:05 GMT
Hi all,
I've posed similar questions before but not specifically garnering opinion on peoples own experiences and own personal preferences, so I'll give mine too.
I have a good mains supply in my house, it's a new-build (late 2019) and has a nice RCD box and although there are a few structural issues the electrics have been done properly. I'm not far from the local sub station, 200 yards or so (I assume its this one).
My preamp has some transformer hum slightly audible at listening position, as does my phono stage (both tube based with tube rectifiers). I managed to fix a very buzzy transformer on another phono stage by completely isolating it from the chassis, it went from 'swarm of bees' to dead silent, I was very surprised. Unfortunately this is not really possible on either of my other bits of kit so I'm wondering about adding some filtering/DC blocking etc.
Most literature and thinking implies that any filtering should only be applied IF you have a specific problem (as I feel I do slightly) as it does cause some audible degradation to the sound. The SQ is only really improved with filtering in these situations, if the mains is poor to begin with or there are many switching supplies/appliances connected to the same ring, causing issues.
I must agree my experience reflects this completely and as long as conditions are optimal ALL my kit sounds at its best plugged directly into unfiltered sockets/outlets.
I have my main power amplifier plugged directly into the wall outlet, then the rest of my components plugged directly into an unfiltered power strip. The strip does have a row of filtered sockets but the SQ takes a dive and loses dynamics and punch if anything is plugged into them. I'm assuming this is because the component in question cannot quickly draw the current it requires for dynamic demands of the music (more power and maybe pre-amp's rather than DAC's I'd suspect).
Aside from getting a full power conditioner generating a 'perfect' sine wave (or whatever) I'm not really sure what I can do without potentially causing a drop in SQ, not something I wish to do, ever!
I tried a DC blocker once and it did interfere audibly, can't quite remember conditions exactly but I know I didn't care for the result.
Just wondered if anyone has come across a satisfactory solution for similar issues but other than the conditioner and further isolating the noisy transformers from their chassis', I'm struggling to improve things.
To be honest it's a bit nit-picky as the overall sound is superb but on ultra quiet passages I can't help but notice the transformers in the background.
I'm wondering if a dedicated mains block with star grounding and individually wired sockets (rather than in series which they are in the strip at the moment I think) would yield any improvement although I fear it's the small amount of DC on the mains and the design of components and the transformers which are to blame.
All help and advice much appreciated.
Cheers
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Post by macca on Aug 19, 2021 15:22:57 GMT
You could try a DC blocker but my understanding is that DC is not automatically the cause of the problem, in fact it's unlikely to be DC.
Only basing this on what I've read.
If it doesn't fix the problem and you can't modify the equipment sell it on and buy units that don't hum. Plenty of valve kit without this problem which suggests it's a result of poor design and/or build quality not anything to do with the mains supply.
I've never had this issue with any kit I've ever owned despite owning hundreds of units over the years across 9 different houses (many of which had electrics that were old when Noah was a lad).
I did have an A/V receiver that hummed once it warmed up but that turned out to be a dodgy component, nothing to do with the traffo or DC.
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optical
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Post by optical on Aug 20, 2021 7:11:24 GMT
You could try a DC blocker but my understanding is that DC is not automatically the cause of the problem, in fact it's unlikely to be DC. Only basing this on what I've read. If it doesn't fix the problem and you can't modify the equipment sell it on and buy units that don't hum. Plenty of valve kit without this problem which suggests it's a result of poor design and/or build quality not anything to do with the mains supply. I've never had this issue with any kit I've ever owned despite owning hundreds of units over the years across 9 different houses (many of which had electrics that were old when Noah was a lad). I did have an A/V receiver that hummed once it warmed up but that turned out to be a dodgy component, nothing to do with the traffo or DC. Yeah it is quite annoying as I too have had valve kit which runs absolutely silently. The preamp especially is susceptible, I suspect due to it's ability to run all kinds of different rectifiers and preamp tubes rendering it not quite perfectly suited to any particular rectifier/pre tube combo. From a purely pragmatic perspective, changing to a different pre and phono stage would be the way to go. It's a no go here though as I wouldn't get near their performance for their price (hence my purchase of them!). It's not even particularly bad just more of an annoyance than a genuine issue. As soon as music is playing it's not really audible and only on the quietest passages or between tracks does it distract. Anyway - UPDATE: As the chassis of the pre is quite thin and the noise of the transformer 'reverberates' inside, I decided to place a little granite 'coaster' with some soft feet on top, this seems to have dulled/damped the resonance of the buzzing transformer a little. Maybe by 30-50% actually, which is enough to bring it further into the realms of acceptable noise. Additionally I've plugged the phono stage into a different power strip from another outlet in the room and it too has gotten a lot quieter, for what reason I cannot say. Whatever reason the transformer seems a lot happier connected to this outlet. This is a win for experimentation, I just thought I'd try a couple of left-field changes/tweaks and it seems to have improved things, just wish I could explain exactly why. If I was to guess, it seems I've dampened the resonance of the chassis of the preamp (which was amplified by the open space in the chassis). As for the preamp, maybe it's getting an improvement in the stability of the voltage or the longer power cable is helping somehow? Less clear on that one, it is quieter though by some magnitude, along with a lower noise floor through the speakers too. If I can try some DC blocking without losing money (try before buy or something) I still may investigate that. Cheers |
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Bigman80
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Post by Bigman80 on Aug 20, 2021 7:25:51 GMT
There are two reasons suggested for transformers buzzing:
1) Under Spec for the UK
2) DC
I have never solved a buzzing transformer with a DC blocker.
Usually, our friends on the continent use a 230v Traffo. The UK is still 240v and above. 247v at times here, and if the transformer is not of good enough quality, I found them to buzz audibly.
Once heard, it drives me crazy.
There are also UK manufacturers that use budget traffos, and they too seemed to be like a bee hive.
The only absolute fix is to get proper rated traffos installed.
All of my builds use properly rated UK spec traffos for this reason.
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optical
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Post by optical on Aug 20, 2021 7:36:07 GMT
There are two reasons suggested for transformers buzzing: 1) Under Spec for the UK 2) DC I have never solved a buzzing transformer with a DC blocker. Usually, our friends on the continent use a 230v Traffo. The UK is still 240v and above. 247v at times here, and if the transformer is not of good enough quality, I found them to buzz audibly. Once heard, it drives me crazy. There are also UK manufacturers that use budget traffos, and they too seemed to be like a bee hive. The only absolute fix is to get proper rated traffos installed. All of my builds use properly rated UK spec traffos for this reason. Yup, both bits of kit spec'd for "Europe/UK" but more likely happy at 230v rather than 248 which I can experience in my house! Yeah a DC blocker I tried a while ago was absolute tripe, it was a cheapo one though. To be honest I now have to listen intensively to hear it now. There is a plan hatching to over-haul the power section of the 686 . . . . maybe I need to chuck the phono stage and preamp a certain someone's way also . . . . ahem. |
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Bigman80
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Post by Bigman80 on Aug 20, 2021 7:38:21 GMT
There are two reasons suggested for transformers buzzing: 1) Under Spec for the UK 2) DC I have never solved a buzzing transformer with a DC blocker. Usually, our friends on the continent use a 230v Traffo. The UK is still 240v and above. 247v at times here, and if the transformer is not of good enough quality, I found them to buzz audibly. Once heard, it drives me crazy. There are also UK manufacturers that use budget traffos, and they too seemed to be like a bee hive. The only absolute fix is to get proper rated traffos installed. All of my builds use properly rated UK spec traffos for this reason. Yup, both bits of kit spec'd for "Europe/UK" but more likely happy at 230v rather than 248 which I can experience in my house! Yeah a DC blocker I tried a while ago was absolute tripe, it was a cheapo one though. To be honest I now have to listen intensively to hear it now. There is a plan hatching to over-haul the power section of the 686 . . . . maybe I need to chuck the phono stage and preamp a certain someone's way also . . . . ahem. 🤣🤣 What you need is a listen to a BT2.....that will solve all your issues 🤣 What power supply is in your 686? |
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optical
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Post by optical on Aug 20, 2021 7:43:18 GMT
Yup, both bits of kit spec'd for "Europe/UK" but more likely happy at 230v rather than 248 which I can experience in my house! Yeah a DC blocker I tried a while ago was absolute tripe, it was a cheapo one though. To be honest I now have to listen intensively to hear it now. There is a plan hatching to over-haul the power section of the 686 . . . . maybe I need to chuck the phono stage and preamp a certain someone's way also . . . . ahem. 🤣🤣 What you need is a listen to a BT2.....that will solve all your issues 🤣 What power supply is in your 686? Just to standard little switching SMPS thingy . . . . so improvements will be dramatic I suspect. May as well go OCC wiring internally too . . . . Oh that's a big yes to the BB2/3. I think I said on another thread this phono stage is basically a stop gap until I can get hold of a 'proper' end-game one. To be honest the rest of the vinyl front end isn't up to that standard (yet) . . . . I may be looking to flog my modded LP12 and a few other bits to assemble a vinyl front end which competes but you know how it is . . . mortgage, kids, cars etc . . . . If I'm 'good' for a bit longer (and stop buying any 'fluff') I should be good to assemble something in the new year. One thing is for sure, I will be speccing it with ODAM's . . . . |
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Post by electronumpty on Aug 20, 2021 10:15:23 GMT
When I swapped my Toroid for an o core it took away a lot of noise. So much so that I plan to do the same in my DCB1 in the future. I don't think I have a mains issue mind, it was just quieter anyway. It cleaned the whole sound up.
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Bigman80
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Post by Bigman80 on Aug 20, 2021 12:01:32 GMT
When I swapped my Toroid for an o core it took away a lot of noise. So much so that I plan to do the same in my DCB1 in the future. I don't think I have a mains issue mind, it was just quieter anyway. It cleaned the whole sound up. O-CORE traffos are fantastic things aren't they! |
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Post by electronumpty on Aug 20, 2021 12:39:38 GMT
Aye, bit of a revelation, cheaper than the toroid too.
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optical
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Post by optical on Aug 20, 2021 13:30:21 GMT
Hmmmm....
Seems to be resounding accolades for the O cores then....
Thanks for the recommendations chaps.
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Post by electronumpty on Aug 20, 2021 14:01:23 GMT
James transformers, in China but reasonable prices and turnaround times. They do potted and shielded options too.
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Post by hifinutt on Sept 22, 2021 21:39:51 GMT
Been trying my isotek syncro dc blocker on and off on my modest sacd player , I swear it makes everything sound sharper with more attack and sparkle
Shame really as I would like to sell it to raise funds ! However it's staying in at the moment as very captivating
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Post by firebottle on Sept 23, 2021 6:32:56 GMT
Yup,both bits of kit spec'd for "Europe/UK" but more likely happy at 230v rather than 248 which I can experience in my house! Yeah a DC blocker I tried a while ago was absolute tripe, it was a cheapo one though. To be honest I now have to listen intensively to hear it now. There is a plan hatching to over-haul the power section of the 686 . . . . maybe I need to chuck the phono stage and preamp a certain someone's way also . . . . ahem. You could power both bits of kit through a bucking transformer to lower the voltage by 20V. I have a number of suitable transformers to do that, however they have a problem, they buzz  |
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