a question of noise!

[the_doc735]

....a question of noise!

Does anyone have experience of the sophia electric 91-01 300B? (monoblocks)

Is it in its nature for transformers to buzz and hum (vibrate)? (with hum trim pots)

I just wondered because my puresound 2A3 was really quiet i.e. silent/no noise! (with no hum trim pots)

[RothwellAudio]

No, transformers shouldn't hum/buzz. It indicates to me that the transformers are poor or the design is poor or there is a fault somewhere. If you're lucky it could just be a case of resetting the bias so the current drain is as it should be.

[the_doc735]

No, transformers shouldn't hum/buzz. It indicates to me that the transformers are poor or the design is poor or there is a fault somewhere. If you're lucky it could just be a case of resetting the bias so the current drain is as it should be.

many thanks!

I seller said: "I don't think it is a fault as it would be unlikely that both monoblock's have developed the exact same fault at the exact same time - yes?". "Although from your sound file, it looks like there is a 50Hz. frequency that should not be there!!". These are step down 230v - 120v action'ed by an airlink BPS0508.

Also, see this: https://www.audioaficionado.org/showthread.php?t=15595&page=3 POST 27. Sounds like my problem to!

sent you a sound file of the buzz via email.

[337alant]

You may have a problem with DC on your mains?
http://sound.whsites.net/articles/xfmr-dc.htm
Are you using any of those home plugs for networking they work on the earth network so could be a source of noise
Alan

[anthonyTD]

Make sure they are meant to be run on 240v plus, a lot of equipment made these days are 230v, even then, they may only need 220v on them for all the voltages on the secondaries to be correct, basicaly; the over voltage in some cases can cause the Transformers to hum.
If your not sure, get in touch with the manufacturers.
Hope this helps. :)
A...

[walpurgis]

If it is a DC issue, this recent thread may be of interest: http://theartofsound.net/forum/showthread.php?52821-Sjostrom-DC-Blocker

[RothwellAudio]

That sound file doesn't sound like transformer buzz at all to me - it sounds like humming coming from the speakers. A hum in the signal can have many causes but in this instance I suspect power supply ripple. I could be wrong about that though.
Of course, hearing the humming in isolation doesn't give any indication of the signal-to-noise ratio. That hum could be at a very low level or a very high level, there's no way to tell. Also, no indication of whether or not the hum goes up/down with the volume control.

Anyway, it doesn't sound like transformer buzz and isn't caused by DC on the mains.

[the_doc735]

You may have a problem with DC on your mains?
http://sound.whsites.net/articles/xfmr-dc.htm
Are you using any of those home plugs for networking they work on the earth network so could be a source of noise
Alan

I'll try unplugging them!
thanks!

[the_doc735]

Make sure they are meant to be run on 240v plus, a lot of equipment made these days are 230v, even then, they may only need 220v on them for all the voltages on the secondaries to be correct, basicaly; the over voltage in some cases can cause the Transformers to hum.
If your not sure, get in touch with the manufacturers.
Hope this helps. :)
A...

These sophias are 120v~ I,m using a step down transformer from 230v (i.e. airlink BPS0508) as stated above!

[the_doc735]

If it is a DC issue, this recent thread may be of interest: http://theartofsound.net/forum/showthread.php?52821-Sjostrom-DC-Blocker

thanks!

[the_doc735]

That sound file doesn't sound like transformer buzz at all to me - it sounds like humming coming from the speakers. A hum in the signal can have many causes but in this instance I suspect power supply ripple. I could be wrong about that though.
Of course, hearing the humming in isolation doesn't give any indication of the signal-to-noise ratio. That hum could be at a very low level or a very high level, there's no way to tell. Also, no indication of whether or not the hum goes up/down with the volume control.

Anyway, it doesn't sound like transformer buzz and isn't caused by DC on the mains.

The microphone was 1cm from the OPT on one of the sophia's, but they are both same anyway. The speakers are about 4 foot away from the amps - to either side. There is a very very small hum from the speakers too that is almost inaudible unless you jam you ear right on the speaker itself! The amps can JUST be heard when sat about 5 feet away and can easily be masked when there is talking on a TV set for example. THe noise level doesn't vary and these are like power amps with NO volume controls at all; all there is - is a on/off switch on each monoblock.
Also, when I switch on my REL Stampede sub woofer the deep bass hum through the speakers increases (say) 'six fold' and can almost be heard on quiet passages of music! Not good for amps costing $4999!
Before these amps I had a puresound 2A3 and a Lyric Ti 60. BOTH of these were completely silent WITH THE EXACT SAME SYSTEM (i.e. only the amps changed, nothing else)! So, I can't really blame the speakers, mains, DAC, laptop, interconnects, home plugs, pure AC sign wave generator, APC EMI/RFI blocker etc. etc.

Many thanks - hope this helps?

[the_doc735]

You may have a problem with DC on your mains?
http://sound.whsites.net/articles/xfmr-dc.htm
Are you using any of those home plugs for networking they work on the earth network so could be a source of noise
Alan

unplugging the 'home plugs' make no difference.

[Arkless Electronics]

The DC, if there is any... won't make it past your step-down transformer... ( I guess theoretically it could be causing an asymmetrical magnetic loading on the step-down transformer, such that it distorts the mains and passes on this distorted mains, causing the less good quality transformers in the amps to buzz.. clutching at straws here though!) Some transformers do buzz a bit and from what you describe I reckon yours are thus...

Sometimes transformers intended for 60Hz mains will buzz rather on UK 50Hz mains if money has been kept tight on the spec.. it often is!. Nowt you can do about that... unless your "pure sine wave generator" is a mains re conditioner with the option to output 60Hz of course... 50Hz transformers in other kit should be fine running on that.

It is true that gear intended for 220V mains is often exported to the UK and our 240V mains can give hum in some cases, but if this is 120V and being powered by a 240v to 120 v step down transformer all should be well... unless your step-down transformer is nowhere near up to the job and is itself saturating and passing the distortion on to the amps' mains transformers.... If so I would expect your step-down transformer to be running rather hot and probably buzzing itself. Beware when judging "rather hot" that 50-60C or so can be a normal running temp after several hours use for lower specced transformers.

I have come across plenty of UK gear with audible mains transformer hum as well though so this is something that can just be intrinsic to some amps.
If you can see the nuts and bolts holding the transformer laminations together it's worth checking they are not loose as this can be the cause...

The hum issue with the sub is probably unrelated.

[RothwellAudio]

The sound file I heard (Paul sent me an email with the file attached) did not have the usual buzzing sound that transformers with rattling (or at least under tightened) laminations make.
I would suggest that the HT voltage should be measured to check if it's what it's supposed to be. Also check the output valves' bias current to see if it's what it should be. Of course, that will require a circuit diagram or a service manual or an email to the manufacturers. However, it should be the first thing to check before anything more drastic is contemplated.

[the_doc735]

The sophia Electric 91-01 300B has been returned as it did not work correctly on the UK mains power grid. ;)

[Barry]

Sometimes the transformers used in US gear are optimised for the 60Hz mains frequency. I have heard of cases when such equipment is used in the UK (where the mains frequency is 50Hz) the transformer laminations can vibrate and buzz. If there was a problem with DC on the mains, the 'buzz' would be at 100Hz.

[the_doc735]

Sometimes the transformers used in US gear are optimised for the 60Hz mains frequency. I have heard of cases when such equipment is used in the UK (where the mains frequency is 50Hz) the transformer laminations can vibrate and buzz. If there was a problem with DC on the mains, the 'buzz' would be at 100Hz.

thank you, yes true, I heard that too, now I have hands on experience of it. ;)

[the_doc735]

http://www.pinkfishmedia.net/forum/showthread.php?t=146788

...going to get a JOHN WOOD 6L6 AMP.

http://www.retrosellers.com/features577.htm

http://jwoodaudio.com/

21088

[the_doc735]

Well, got the 6L6 by John Wood:

What can I say:

Gob smacked! Speechless! There simply aren't enough superlatives in the dictionary to describe it!

This is completely inaccurate:

http://theartofsound.net/forum/showthread.php?34234-John-Wood-Audio-a-tale-of-woe

The guy is really really good and the amp is amazing!

In his defense: John said:

"Well you all ways get one and he found out you can try and get your money back and keep the goods and I am not the only one he as tried it with .I have more than 1000 bits of audio out there and as you can see my second hand price is one of the highest in the world so what does that tell you ?.He is just a thief and A liar.
John"

Grab one now BEFORE 'the word' gets out! These will take off in the future, no doubt about it! They are incredibly good value at the moment, I.M.H.O they could be sold in the same price range as Audio Research, McIntosh & Ayon etc. NO JOKE!

In fact I would like to hear Audio Research, McIntosh & Ayon amps in my setup to compare ~ ANY OFFERS? (bake-off).

PS: John has offered to give my 6L6 a FREE health check and transformer dip, so that it will be as good as new! Can't say fairer than that - can you? Good bloke?

[the_doc735]

http://www.pinkfishmedia.net/forum/showthread.php?t=146788

...going to get a JOHN WOOD 6L6 AMP.

http://www.retrosellers.com/features577.htm

http://jwoodaudio.com/

21088

https://hifiwigwam.com/forum/topic/59092-john-wood-amps/

[the_doc735]

Well, got the 6L6 by John Wood:

What can I say:

Gob smacked! Speechless! There simply aren't enough superlatives in the dictionary to describe it!

This is completely inaccurate:

http://theartofsound.net/forum/showthread.php?34234-John-Wood-Audio-a-tale-of-woe

The guy is really really good and the amp is amazing!

In his defense: John said:

"Well you all ways get one and he found out you can try and get your money back and keep the goods and I am not the only one he as tried it with .I have more than 1000 bits of audio out there and as you can see my second hand price is one of the highest in the world so what does that tell you ?.He is just a thief and A liar.
John"

Grab one now BEFORE 'the word' gets out! These will take off in the future, no doubt about it! They are incredibly good value at the moment, I.M.H.O they could be sold in the same price range as Audio Research, McIntosh & Ayon etc. NO JOKE!

In fact I would like to hear Audio Research, McIntosh & Ayon amps in my setup to compare ~ ANY OFFERS? (bake-off).

PS: John has offered to give my 6L6 a FREE health check and transformer dip, so that it will be as good as new! Can't say fairer than that - can you? Good bloke?

https://hifiwigwam.com/forum/topic/59092-john-wood-amps/

[walpurgis]

Why would two court decisions against him be "inaccurate"?

I don't see the relevance of the link to ancient Wam posts.

[the_doc735]

Why would two court decisions against him be "inaccurate"?

I don't see the relevance of the link to ancient Wam posts.

"Why would two court decisions against him be "inaccurate"?" ~ don't know what you are referring to in the "link to ancient Wam post" ?

The relevance is in support of his excellent products and character; & it helps build a case in his defense against this: http://theartofsound.net/forum/showthread.php?34234-John-Wood-Audio-a-tale-of-woe

Have you spoken to John Wood face to face (in person) regarding these issues? (in order to evaluate his version of events or are you simply bias to the case for the prosecution with no fair hearing for the defense?), I do believe that courts can make mistakes and hang innocent victims!

[Lawrence001]

Heard the amp in question at Scalford this year thanks to Al, it looked superbly built and sounded great.

Sent from my NEM-L51 using Tapatalk

[Lawrence001]

The sophia Electric 91-01 300B has been returned as it did not work correctly on the UK mains power grid. ;)Can I ask where you bought them from? I imagine some sellers would blame the mains/cables/RF interference etc.

Sent from my NEM-L51 using Tapatalk

[walpurgis]

are you simply bias

Ah. It's bias is it? Since when does asking a question equate to bias?

And you suggest that two court rulings were "inaccurate" without offering anything to back this up.

And I didn't get the Wam link. It's old and says nothing useful.

[Macca]

"

Have you spoken to John Wood face to face (in person) regarding these issues? (in order to evaluate his version of events or are you simply bias to the case for the prosecution with no fair hearing for the defense?), I do believe that courts can make mistakes and hang innocent victims!

I don't really know why you are bringing this up. You have one of his amps and like it, is that not enough? Fact is John Wood handled that situation very badly from a customer service point of view and had the opportunity on several occasions to put his version of events in Court and did not bother. Nor did he comply with the Court's ruling. How he handles these things is, of course, up to him, but hardly surprising that he experienced some blowback from it.

The fact that the purchaser in that particular incident auctioned the amp for charity just to be finished with the whole deal would indicate to me that his motive was not to get an amp for free, since he ended up a grand out of pocket and with nothing to show for it.

[the_doc735]

Heard the amp in question at Scalford this year thanks to Al, it looked superbly built and sounded great.

Sent from my NEM-L51 using Tapatalk

:exactly:

[the_doc735]

Can I ask where you bought them from? I imagine some sellers would blame the mains/cables/RF interference etc.

Sent from my NEM-L51 using Tapatalk

It doesn't matter now anyway, they came from Germany, bought as new but when I returned them a few weeks later they said the valves were now worn out!! Ridiculous, in the extreme or what?

[the_doc735]

Ah. It's bias is it? Since when does asking a question equate to bias?

And you suggest that two court rulings were "inaccurate" without offering anything to back this up.

And I didn't get the Wam link. It's old and says nothing useful.

asking a question isn't bias, but taking one side without hearing the other (side) IS!

I am not suggesting that this ruling was inaccurate, I am suggesting that this post (tail of woe) is a defamation of his character.

As I already said, The relevance of the wam post is in support of his excellent products and character; & it helps build a case in his defense against this: http://theartofsound.net/forum/showt...-a-tale-of-woe

Have you spoken to John Wood face to face (in person) regarding these issues? (in order to evaluate his version of events or are you simply bias to the case for the prosecution with no fair hearing for the defense?), I do believe that courts can make mistakes and hang innocent victims sometimes!

[the_doc735]

I don't really know why you are bringing this up. You have one of his amps and like it, is that not enough? Fact is John Wood handled that situation very badly from a customer service point of view and had the opportunity on several occasions to put his version of events in Court and did not bother. Nor did he comply with the Court's ruling. How he handles these things is, of course, up to him, but hardly surprising that he experienced some blowback from it.

The fact that the purchaser in that particular incident auctioned the amp for charity just to be finished with the whole deal would indicate to me that his motive was not to get an amp for free, since he ended up a grand out of pocket and with nothing to show for it.

I am simply saying that for every 100 deals that go right, it is not fair to focus on the one that went wrong, it distorts the overall impression of the man and his work, as the WAM and PINK FISH threads attest to - there are plenty of recommendations for this brand. FACT!

I am bringing this up because someone needs to show the brand in a different light, as it's not all bad, as the 'WOE' thread seems to suggest! Anyone reading 'the woe' thread should NOT be put off purchasing a WOOD AMP, because of it!!

[walpurgis]

asking a question isn't bias, but taking one side without hearing the other (side) IS!

I am not suggesting that this ruling was inaccurate, I am suggesting that this post (tail of woe) is a defamation of his character.

As I already said, The relevance of the wam post is in support of his excellent products and character; & it helps build a case in his defense against this: http://theartofsound.net/forum/showt...-a-tale-of-woe

Have you spoken to John Wood face to face (in person) regarding these issues? (in order to evaluate his version of events or are you simply bias to the case for the prosecution with no fair hearing for the defense?), I do believe that courts can make mistakes and hang innocent victims sometimes!


This is getting like a needle stuck in its groove.

And why the hell would I want to speak to John Wood anyway?

[Virkon]

Doc you won't even like it next week you'll be buying something else.

[Lawrence001]

To me the moral of the story was, if you order a hand made valve amp and the maker strongly advises you not to have it delivered as he can't guarantee it will arrive safely, it's probably best to collect it, or get one from somewhere else.

Sent from my NEM-L51 using Tapatalk

[agk]

Just to get back on topic for a moment I notice that your stepdown tx is 230v. UK mains is usually 240v+. That may not have been helping.

[the_doc735]

Just to get back on topic for a moment I notice that your stepdown tx is 230v. UK mains is usually 240v+. That may not have been helping.

Hi, yes! - However the stepdown tx wasn't run directly from the UK mains, it was run from a pure sine wave regenerator that gives out a constant and stable 230v. With slightly unstable mains input of 240v +.

[the_doc735]

Doc you won't even like it next week you'll be buying something else.

care to put your money where your mouth is? (a bet)

[the_doc735]

To me the moral of the story was, if you order a hand made valve amp and the maker strongly advises you not to have it delivered as he can't guarantee it will arrive safely, it's probably best to collect it, or get one from somewhere else.

Sent from my NEM-L51 using Tapatalk

well - yes! - exactly.

[the_doc735]

And why the hell would I want to speak to John Wood anyway?

hey man, it's cool, stay calm...

(in order to evaluate his version of events?)