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Post by pinkie on Jul 28, 2015 5:57:29 GMT
Yes thanks James. Great evening. I'll post a bit more when I have a keyboard. I came home to dozens of eBay questions
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Post by pinkie on Jul 28, 2015 8:41:53 GMT
I'll break this into several posts, so as not to be too long. Another "tune" that got played a lot was Santana's Guitar Heaven CD - particularly "While my guitar gently weeps". Together with Adele Rolling in the Deep, Dire Straits Brothers in Arms, I found the Santana good listening. No electric chair, no cadmium poisoning and survived the Balanced Mains. I think the Window and a bit of daylight made it seem less "heavy". Lets deal with the safety issue first. Around the time when a certain manufacturers Balanced Mains was hitting the forum headlines, James I know got tired of my interest in safety (he was making a few balanced supplies for friends). But we have reached a common understanding that they are not Satan's spawn or lethal weapons per se - rather, talking ignorant nonsense about safety aspects is what is dangerous. At that time I was struggling for "real" examples of the issue for not having RCD protection in a HiFi context. Last night we had an example MODERATION - The following paragraph describes unsafe and dangerous practice which is not condoned in any way by this forum. Do NOT follow this example. Please read the forum notice regarding tampering with mains power.Hum - yep, my old friend plagued us again. We were running exclusively off the balanced mains (I thought), but when we plugged the Pip in, I became aware of a faint hum (I suspect it was there before, but I hadnt approached the speakers). James is more sanguine about this than I am , and was happy to carry on, but I don't do noise!!! So I fixed up a wire to the Pip chassis ground and prodded for another ground on the SECA - which has its lid off. James offered the central signal ground point, near the bottom of the back of the chassis (which didnt work - see below). Now, the risk is fairly small (and we survived it) even for a wonky-eyed weary boned wobbly old git like me. But real. One hand is resting on metal chassis for support, and the other is poking around with a bit of wire looking for earth, but with plenty of lives to fall on (twice as many with Balanced Power!). If this had been plugged into the regular mains at my house, and I had slipped then the RCD's would have protected me. On James system, with a Balanced Power Supply and no RCD's on the output of that device - I'm fried. Of course, I should have turned off the power before reaching for a ground - but how do you hear the hum clear? A chassis ground point on the exterior of the amp would have helped. Anyway - you get my point - real life example for the BPS no RCD electrical safety issue. The point is - it is not that the device itself is inherently dangerous - but misunderstanding its use IS dangerous. And claiming authoritative knowledge and stating that RCD's on the input of the BPS would protect me and RCD's on the output would be a redundant waste of time, is criminally irresponsible in my view. OK - back to hum. Whilst James was outside taking a call I traced it to the Ibook (Apple laptop job) - running that from batteries fixed the problem. It was running from a separate mains supply - not the BPS. Not sure I quite understand why we hasd hum, as ever. The unearthed power supply would be capacitively coupling mains to the system ground in the laptop, so grounding the laptop properly to earth (or removing the mains charger) fix it, but there was only a digital connection to the HiFi - so how were we picking up the hum?  The USB lead may have connected the laptop ground with the noise to the DAC, why didn't my attempts to ground the dac fix it? Anyway - tunes and amplifiers in the next post  |
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Post by pinkie on Jul 28, 2015 9:15:03 GMT
As James noted we switched his "passive pre" out, and switched the Pip in. I would like to say the transformation in sound was due to the outstanding qualities of the Pip 2 passive preamp, but I'm not sure a cheap carbon pot with a couple of RCA sockets wired to it was the stiffest competition the Pip has ever faced. Anyway, before, if I'm honest, I was struggling. After I could sit back and enjoy - even though James's system is very different to mine. All comments about "how it all sounded" have to be seen in the context that we clearly have different takes on what we want our music to sound like. There is a world of difference between my cling-film in a high voltage bed-frame ESL63's, and James paper cones on plywood open baffles. First the SECA - what an awesome bit of kit! The case work is to be finished with glass, so it will always be possible to oggle the innards - especially since it has to be at the top of the pile, to make flipping the burgers easier. (It gets warm). A really smooth sounding mellow amp - and that bit special I know to have put it together himself. I have the same daft sentimental attachment to my PT. I also feel, regardless of its absolute quality, that it suits both James speakers and his listening tastes exceptionally well. It has a rich deep extended and controlled bass, which is clearly important to someone with 15" cones, and who picks music with bass and sparse instrumentals or vocals like the Sting tracks, and the Jewish harp track (James - what were they?) which he picked to listen to. The comparison with the Benchmark, reminded me of the old PT v LP12 difference. Although as James noted, it was maybe just that bit too much in the bass in that room, if you are focussed on bass - the SECA delivers in spades, and the result on that sort of music is warm and rich and highly musical - very easy to sit back and enjoy. I was a bit surprised that the bass on the Benchmark seemed subjectively less rich - although plenty strong and detailed and tuneful. Maybe that is down to the claims of John Siau that the lack of low level distortion provides a cleaner more "true" sound. Maybe it was down to cables. (Yes , I know who I am, and I know what I just wrote  ) . My friend from Holland was over recently, and felt the Benchmark lacked "sparkle" but was solid in the bass. I don't think James would say there was a lack of sparkle. The difference, maybe - at home I have a set of balanced leads made using Klotz MC5000. I took the short thin wired set that Owen made for me to James's because it was more convenient. He was using Klotz MC5000 as his interconnect. Had I known that before I set off, I would have bothered to get my MC5000 set out - since then there would have been no possibility that ic's were contributing. I am due to make up a couple more sets of 2m leads (I need 2m ic's at home at the moment, or I have to have ugly chord flat speaker cables draped around in sight). The Benchmark's basic quality showed up in the detail it produced - although I much prefer it on the ESL63's to James speakers, which to my ear are a bit "cuppy", and lack the airy "speakerless speaker" of the 63's. The same applies to stereo depth - more obvious on the Benchmark, but even more so on the cling film jobs at my house. It wasn't just that you heard extra things, or even that they were placed more precisely and "independently" with the Benchmark - it was the way each voice or instrument sounded distinctly real. So, as an example - the SECA would produce tight rich bass music, but it wasn't so obvious what sort of bass was playing it. On the Dave Migden tracks (which I know well live, and at the studio) the backing vocals (Dave dubbed in, along with Goldie Reed) sounded like separate distinctly different voices, rather than a backing vocal mix or synthesis of all the voices. But that isnt to say the SECA sounded false or lost - these were both fine amplifiers .We were comparing 2 "rather better" ones, and both produced excellent results. I just wonder what the cables contributed And as James noted - never mind that fannying about with kit, we listened to some great sounding music, and enjoyed a nice glass of wine. Thanks again Soveriegn And yes, John and Steve, it would be nice to do something - sooner rather than later. We might be in France any day now  |
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Post by guy on Jul 28, 2015 9:22:59 GMT
checking the slack on a car alternator belt, by hand, with the engine running; pissing on a toaster to stop the bread burning; using petrol to help light a bonfire; prodding around a live circuit with a bit of wire to find an earth point all seem to be examples of pretty irresponsible behavior to me!
If anything went wrong there would be only one person to blame and it certainly wouldn't be the manufacturer or supplier.
Perhaps it is time to give up on this one Pinky.
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Post by pinkie on Jul 28, 2015 9:47:09 GMT
No Guy. Pissing on the toaster is fine. Modern UK wiring regulations require the household supply to the toaster to be protected by an RCD which I haven't by-passed as a result of misleading information provided by an expert on a forum. Plugging the toaster into a BPS and pissing on it would be dangerous.
Yes - I'm sure I should have turned off the power, connected the earth, turned back on the power, listened for the hum - but we don't. Especially when we are used to the idea that an RCD safety blanket protects us.
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Post by guy on Jul 28, 2015 10:06:00 GMT
may be fine for you, certainly isn't for me.
Anyway, are you really that determined to ignore the point I make just to continue with a silly vendetta? It now makes you look rather sad.
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Post by dvh on Jul 28, 2015 11:20:46 GMT
may be fine for you, certainly isn't for me. Anyway, are you really that determined to ignore the point I make just to continue with a silly vendetta? It now makes you look rather sad. He just wasn't trying hard enough. Where was the toddler with the knitting needles, or the teenager with wet hair and a faulty hairdryer, or the aged parents with the electric hedge trimmer? |
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Post by Sovereign on Jul 28, 2015 11:37:54 GMT
Pinkie could you have not put more effort in and write a longer post , not like you at all  |
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Post by Sovereign on Jul 28, 2015 12:44:37 GMT
I have to agree with much of your listening points there Richard, long term the Benchmark would be an incredible amp, but I feel I may get a little tired of it as I have all other A/B amps. Not that this is one but long term they don't suite my tastes, as bloody amazing as some of them are; namely NVA and Classic Exposure, I still have the NVA TSS and when I play it I love it's immediacy., But I prefer this SECA sound. As we both agree the SECA (must find a proper name for this amp, maybe luscious Lucy or something) delivers so much full on bass that I need to sort out my room acoustics, as when we have heavy bass notes going the room can't quite cope. I must get this room treated, even if it means starting with a couple rolls of carpet, and round off some of the corners of the room etc, I have a feeling it would give me the desired effect I am looking for. But for me it's a lot more than just being about big bass, I find Collins SECA amp to be so well-balanced it gives such an incredible musical presentation, fantastic tonal colour, and an intimacy like I haven't found elsewhere . As. I was saying to Richard last night the richness of voices is incredible, it's like you can hear right to the back of someone's throat, weird I know, and perhaps not the best line to use in the marketing of this amp, but true none the less.  |
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Post by Sovereign on Jul 28, 2015 13:33:54 GMT
Lets deal with the safety issue first. Around the time when a certain manufacturers Balanced Mains was hitting the forum headlines, James I know got tired of my interest in safety (he was making a few balanced supplies for friends). But we have reached a common understanding that they are not Satan's spawn or lethal weapons per se - rather, talking ignorant nonsense about safety aspects is what is dangerous. At that time I was struggling for "real" examples of the issue for not having RCD protection in a HiFi context. Last night we had an example I fixed up a wire to the Pip chassis ground and prodded for another ground on the SECA - which has its lid off. James offered the central signal ground point, near the bottom of the back of the chassis (which didnt work - see below). Now, the risk is fairly small (and we survived it) even for a wonky-eyed weary boned wobbly old git like me. But real. One hand is resting on metal chassis for support, and the other is poking around with a bit of wire looking for earth, but with plenty of lives to fall on (twice as many with Balanced Power!). If this had been plugged into the regular mains at my house, and I had slipped then the RCD's would have protected me. On James system, with a Balanced Power Supply and no RCD's on the output of that device - I'm fried. Of course, I should have turned off the power before reaching for a ground - but how do you hear the hum clear? A chassis ground point on the exterior of the amp would have helped. Anyway - you get my point - real life example for the BPS no RCD electrical safety issue. The point is - it is not that the device itself is inherently dangerous - but misunderstanding its use IS dangerous. And claiming authoritative knowledge and stating that RCD's on the input of the BPS would protect me and RCD's on the output would be a redundant waste of time, is criminally irresponsible in my view. I need to add that I don't agree with much of the above here. What I do agree with is electrical information, correct or not, found on hifi forums is not place to educate one self. For some one to say something is categorically safe on a forum is dangerous as we don't know who will read that post or how it will be misinterpreted. MODERATION - The following is not guaranteed to be safe practice since it depends on exactly how the RCDs are wired. Please just don't try it, be safe.I need to stress that should you have poked your wire onto a live terminal or neutral as in my system they are the same thing you would have been fine due to the way the BPS is wired and the fact that there is both an RCD and MCB in the consumer unit feeding my system. An example of this is when I 'fried' my LDR the MCB tripped protecting me, I just replicated the same electrical mistake and again the MCB tripped. I then plugged a piece of hifi equipment that I don't really care about into my Mother Trucker BPS, I linked live to earth and the RCD in the CU which is before the BPS tripped, again keeping me safe. Anyway this thread is really for my SECA build, but I needed to clear up the safety issues of my HIFI. NB. Please, no one to copy what I did above as you may get hurt  |
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Post by Deleted on Jul 28, 2015 13:37:39 GMT
I would suggest the amplifiers are chalk and cheese, having heard one of the Benchmark units recently I see why James prefers the Class 'a' solution, the BM delivers quality performance but in a different vein.
I would further suggest that the BM delivered a 'thin' presentation in comparison while not 'thin' due to the class 'a' rich textural qualities and note decay coupled with the fuller richer bass.
The BM I listened to was paired unfortunately with ATC's at first, these was swapped out to Dyn stand mounts around £6k this resulted in a much better balance of detail/ attack / dynamics and texture.
Horses for coarses.
James which FET's are you using in the amp?
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steve
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Post by steve on Jul 28, 2015 13:37:54 GMT
Jesus HC! What kind of bloody idiot, pokes around inside a live chassis for an earth, with the power on whilst leaning on an earthed metal chassis. Oh yes the RCD will protect me. Yeah right! Total lunacy, irresponsible in the extreme and for Christ sake keep away from valve amps. I really cannot believe what I have just read! |
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Post by Sovereign on Jul 28, 2015 14:06:08 GMT
I would suggest the amplifiers are chalk and cheese, having heard one of the Benchmark units recently I see why James prefers the Class 'a' solution, the BM delivers quality performance but in a different vein. I would further suggest that the BM delivered a 'thin' presentation in comparison while not 'thin' due to the class 'a' rich textural qualities and note decay coupled with the fuller richer bass. The BM I listened to was paired unfortunately with ATC's at first, these was swapped out to Dyn stand mounts around £6k this resulted in a much better balance of detail/ attack / dynamics and texture. Horses for coarses. James which FET's are you using in the amp? Hi Tony I'm not sure of the FET's mate, Colin changed them when he tweaked things at his work shop and said they were different and better than whats on the BOM, Colin will need to comment. If you have heard the Iridium, this is is the Iridium on Roids, it's ridiculous how big and fruity the musical presentation is, yet it's fast and punchy. I would love to hear the Class A you worked on. |
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Post by pinkie on Jul 28, 2015 16:03:16 GMT
James
I'm sorry this is drifting your thread, but an RCD CANNOT protect in that way. It senses the difference between the current in the live and the neutral wires. Any event on the secondary of a transformer can change the total current flowing in the primary circuit, but not how much current flows down the brown wire compared to the blue wire.
This is old ground now - but the only way a fault on the secondary can trip "something" on the primary is if that something is an MCB which is tripped by a current overload. If the device is an RCBO then it is an RCD and MCB combined and you wont know whether a current overload tripped the MCB part or a current imbalance tripped the RCD part
But no event on the secondary of a transformer can create a current imbalance on the primary of a transformer - it is not electrically possible. This point needs to be clearly understood.
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Post by pinkie on Jul 28, 2015 16:09:23 GMT
Jesus HC! What kind of bloody idiot, pokes around inside a live chassis for an earth, with the power on whilst leaning on an earthed metal chassis. Oh yes the RCD will protect me. Yeah right! Total lunacy, irresponsible in the extreme and for Christ sake keep away from valve amps. I really cannot believe what I have just read! THis from someone who posted that a BPS was an isolating transformer of the type used to provide safety (I think bathrooms got mentioned) even though an isolating transformer, in that context, relies on the secondary ground floating and not being bonded to earth. The reason isolating transformers isolate is because, they are different from normal mains where earth provides a path to neutral (to complete a circuit). As it does on a BPS with secondary ground bonded to true earth - to supply a required earth for any class 1 device plugged into it. And whose friend boasts of his tingling experiences from electrocutions. |
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Post by Sovereign on Jul 28, 2015 16:21:42 GMT
James I'm sorry this is drifting your thread, but an RCD CANNOT protect in that way. It senses the difference between the current in the live and the neutral wires. Any event on the secondary of a transformer can change the total current flowing in the primary circuit, but not how much current flows down the brown wire compared to the blue wire. This is old ground now - but the only way a fault on the secondary can trip "something" on the primary is if that something is an MCB which is tripped by a current overload. If the device is an RCBO then it is an RCD and MCB combined and you wont know whether a current overload tripped the MCB part or a current imbalance tripped the RCD part But no event on the secondary of a transformer can create a current imbalance on the primary of a transformer - it is not electrically possible. This point needs to be clearly understood. You mention nothing of an RCD tripping due to an earth fault, this is how and why it tripped. |
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Post by Sovereign on Jul 28, 2015 16:27:41 GMT
Can we move from personal BPS excitement and back to either the SECA amp or last nights visit as this is serious driftage,
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Post by Deleted on Jul 28, 2015 16:33:55 GMT
Hi James
The latest version has a quantified fruit content if you like, lots of texture, depth correct tonal quality and note decay.
It does have the full rich bass, however I have given it a very tight and articulate presence, for a class 'a' room boom is not so much a problem any more.
I found FET choice and feedback topology made quite a significant difference once the ultra stiff power supply was completely sorted.
Sounds like you are really enjoying the fruits of your labour James, well done on the build it is quite satisfying when you put an concept / idea into reality gives you a sense of achievement.
Perhaps in the not too distant future we can tie up and you can give me your thoughts on its sound.
I have just finished a new design myself taken around 3 years on and off and it is a replacement for my current reference and its shaping up to be a bit special.
However not to detract from your success James.
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Post by Sovereign on Jul 28, 2015 16:36:59 GMT
Hooking up would be great, where are you based?
It was Colin's success really, I just lashed it together,
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Post by ChrisB on Jul 28, 2015 17:18:06 GMT
Agreed that this thread has been derailed away from the subject of James' amp and it should go back on track.
But...
This is the most sensible thing said on the posts above concerning mains safety.
What Richard described doing is pretty stupid and shouldn't be repeated. I find it all the more surprising that it comes from someone who has expressed so much concern over electrical safety. These posts remain here long after this discussion has been forgotten about by the contributors and we should all ensure that we do nothing that may encourage anyone coming along later reading it to copy such behaviour.
I have edited Richard's post to include a safety warning.
Hopefully that'll be the end of it and let's get back to chatting about James' amp.
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) . My friend from Holland was over recently, and felt the Benchmark lacked "sparkle" but was solid in the bass. I don't think James would say there was a lack of sparkle. The difference, maybe - at home I have a set of balanced leads made using Klotz MC5000. I took the short thin wired set that Owen made for me to James's because it was more convenient. He was using Klotz MC5000 as his interconnect. Had I known that before I set off, I would have bothered to get my MC5000 set out - since then there would have been no possibility that ic's were contributing. I am due to make up a couple more sets of 2m leads (I need 2m ic's at home at the moment, or I have to have ugly chord flat speaker cables draped around in sight).
