Bigman80
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Post by Bigman80 on Feb 10, 2019 4:49:55 GMT
Seeing the live ther is fir Krell here, I thought it might be a good time to ask the question. Krell clearly are fine examples of the breed. Just wondering what we can learn from the topic and apply to other amps.
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Post by Deleted on Feb 10, 2019 6:19:17 GMT
Simple enough question......or is it?
The answer however is not an easy one to establish.
I don't know !!!
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
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Post by Bigman80 on Feb 10, 2019 8:03:24 GMT
Me neither. Some of the best amps I’ve had used dual transformers, so I’m guessing power supplies are important. My current Sonneteer looks to be nothing special in this respect, but Sonneteer developed it into the Orton by adding another supply and going from there. I assume it’s got a good circuit design and layout to start with, which is taken further by the separate supplies. It also gets pretty hot, but is class A bias for a chunk of its output also important? Ive has cool running amps that have been great, so it can’t be everything.
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Post by alit on Feb 10, 2019 8:26:49 GMT
An amp basically IS it’s power supply, so yes, I’d say that’s of major importance.
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Post by sq225917 on Feb 10, 2019 9:33:58 GMT
Given that some people like well measuring amps and some people like effects pedal amps could it be that theres no 'what makes a good amp' button. We just hitch ourselves to the most obviously different features on those products we like and claim that makes the difference?
Maybe, after just seeing the damn things our minds are already almost made up?
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Post by Deleted on Feb 10, 2019 9:36:58 GMT
Had a lot of Amps and been guilty of buying with looks alone. That's why valve amps are so tempting.
The crudest of them all has been the best.
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Post by antonio on Feb 10, 2019 10:00:22 GMT
I always like one that works, so from my experience I'll stick with SS
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Post by Deleted on Feb 10, 2019 10:12:31 GMT
I always like one that works, so from my experience I'll stick with SS I've had more bother with SS amps than valves. In fact, I've never had a valve amp play up and I must have owned a dozen. |
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Post by Deleted on Feb 10, 2019 11:35:26 GMT
An amp basically IS it’s power supply, so yes, I’d say that’s of major importance. That just about nails it; power supply up to the job then most of the time you get a decent result. |
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Post by Deleted on Feb 10, 2019 15:36:10 GMT
No expert, but I'd say power supply, design simplicity and ability to cope with a real world load, ie amp/speaker interface, which is another story. Decades ago when my Gran died we took in her Marconi radiogram. I used to listen to the radio and play her 78s on it and knew what it sounded like. It used to go off and giving it a knock sometimes brought it back to life. When I looked at it, I found it was the output valve (DH149, I think) that was the culprit, and replacing cured the problem. I was listening to the radio, AM, of course, and the news was on with a live broadcast of people being interviewed on the streets for something or other. As I listened I got quite excited with one particular aspect of what I was hearing. Despite the limitations of AM, I couldn't get over the alacrity (never hear that word in descriptive hi-fi, do you?), "speed" of the voices: there was a total lack of smear and overhang, which made the conversations sound so real. My modest system sounded more hi-fi, but just couldn't do this. In fact, none of the modern gear I've had has been able to replicate it either. The only other item that has managed to do likewise was our Ferguson radiogram. I still remember the energy and life that was to be had from the records I played on it. So, what do I put this down to? Well, I suppose it must be single-ended Class A valve operation with a sympathetic load. I remember the speaker in the Ferguson being a 3 ohm 8" Elac. Thinking about this recently, I've decided that (if a bit late in the day), I should give this route a try. I think the Line Magnetic Boys know where it's at with valves, and I might just go after one of these. It's got the lot: Meters/Stonking-looking valves/40-odd whatts of Single-Ended Class A goodness: If I had £6000 to spare I'd have the other.   |
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Post by Deleted on Feb 10, 2019 15:41:00 GMT
Well goddam, that bottom one has reignited my valve lust.
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Post by sq225917 on Feb 10, 2019 23:38:58 GMT
For me I have to like the look of an amp, it has to function easily and silently without fuss day after day. It has to have great PSRR, good SNR, low THD+ noise and be utterly invariant into any load. Get all that right and anything else is window dressing.
Oh and I have to be able to build it myself.
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Post by Deleted on Feb 10, 2019 23:45:17 GMT
For me I have to like the look of an amp, it has to function easily and silently without fuss day after day. It has to have great PSRR, good SNR, low THD+ noise and be utterly invariant into any load. Get all that right and anything else is window dressing. Oh and I have to be able to build it myself. That must rule a lot of stuff out before you get the the DIY requirements |
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Post by Deleted on Feb 10, 2019 23:57:43 GMT
For me I have to like the look of an amp, it has to function easily and silently without fuss day after day. It has to have great PSRR, good SNR, low THD+ noise and be utterly invariant into any load. Get all that right and anything else is window dressing. Oh and I have to be able to build it myself. Aye Simon, but everything in life is a compromise. You missed out meters. |
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Post by Deleted on Feb 11, 2019 6:39:47 GMT
No expert, but I'd say power supply, design simplicity and ability to cope with a real world load, ie amp/speaker interface, which is another story. Decades ago when my Gran died we took in her Marconi radiogram. I used to listen to the radio and play her 78s on it and knew what it sounded like. It used to go off and giving it a knock sometimes brought it back to life. When I looked at it, I found it was the output valve (DH149, I think) that was the culprit, and replacing cured the problem. I was listening to the radio, AM, of course, and the news was on with a live broadcast of people being interviewed on the streets for something or other. As I listened I got quite excited with one particular aspect of what I was hearing. Despite the limitations of AM, I couldn't get over the alacrity (never hear that word in descriptive hi-fi, do you?), "speed" of the voices: there was a total lack of smear and overhang, which made the conversations sound so real. My modest system sounded more hi-fi, but just couldn't do this. In fact, none of the modern gear I've had has been able to replicate it either. The only other item that has managed to do likewise was our Ferguson radiogram. I still remember the energy and life that was to be had from the records I played on it. So, what do I put this down to? Well, I suppose it must be single-ended Class A valve operation with a sympathetic load. I remember the speaker in the Ferguson being a 3 ohm 8" Elac. Thinking about this recently, I've decided that (if a bit late in the day), I should give this route a try. I think the Line Magnetic Boys know where it's at with valves, and I might just go after one of these. It's got the lot: Meters/Stonking-looking valves/40-odd whatts of Single-Ended Class A goodness: If I had £6000 to spare I'd have the other. All I can say is that I concur with you on Line Magnetic they certainly seem to have got it right I have heard a fair number of their amps being a friend of the local importer. When ever he gets a new one in I get to listen. I myself have the entry level 211IA and it is a very good amp. I also happen to be a friend of the local Ming Da importer, and he gave me a good selection of Ming Da amps to take home and try on my system; another friend and myself had a great Saturday and Sunday giving the Ming Da's a bash. Verdict the little Line Magnetic was significantly better than any of the Ming Da's, the kicker was the Ming Da's were in some cases 10 times the price. I have included a link to his site for interest sake, so you can check out the Ming Da's. We tried out most of them including the SET's. Just search Ming Da. Also check out his other drool goodies. Audio Exchange | High End, Hifi, Buy, Sell, Sale, Naim, Sonus Faber ...
<cite class="iUh30">https://www.audioexchange.co.za/</cite>
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Post by sq225917 on Feb 11, 2019 9:02:01 GMT
For me I have to like the look of an amp, it has to function easily and silently without fuss day after day. It has to have great PSRR, good SNR, low THD+ noise and be utterly invariant into any load. Get all that right and anything else is window dressing. Oh and I have to be able to build it myself. Aye Simon, but everything in life is a compromise. You missed out meters. No need for meters here, that's only for amps with no headroom and poor clipping performance... ;-) |
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Post by pauld on Feb 11, 2019 9:24:00 GMT
What makes a good amplifier? what it sounds like for me.
Smooth, deep but controlled bass, wide and deep soundstage, crystal clear vocals.
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Deleted
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Post by Deleted on Feb 11, 2019 18:48:33 GMT
No expert, but I'd say power supply, design simplicity and ability to cope with a real world load, ie amp/speaker interface, which is another story. Decades ago when my Gran died we took in her Marconi radiogram. I used to listen to the radio and play her 78s on it and knew what it sounded like. It used to go off and giving it a knock sometimes brought it back to life. When I looked at it, I found it was the output valve (DH149, I think) that was the culprit, and replacing cured the problem. I was listening to the radio, AM, of course, and the news was on with a live broadcast of people being interviewed on the streets for something or other. As I listened I got quite excited with one particular aspect of what I was hearing. Despite the limitations of AM, I couldn't get over the alacrity (never hear that word in descriptive hi-fi, do you?), "speed" of the voices: there was a total lack of smear and overhang, which made the conversations sound so real. My modest system sounded more hi-fi, but just couldn't do this. In fact, none of the modern gear I've had has been able to replicate it either. The only other item that has managed to do likewise was our Ferguson radiogram. I still remember the energy and life that was to be had from the records I played on it. So, what do I put this down to? Well, I suppose it must be single-ended Class A valve operation with a sympathetic load. I remember the speaker in the Ferguson being a 3 ohm 8" Elac. Thinking about this recently, I've decided that (if a bit late in the day), I should give this route a try. I think the Line Magnetic Boys know where it's at with valves, and I might just go after one of these. It's got the lot: Meters/Stonking-looking valves/40-odd whatts of Single-Ended Class A goodness: If I had £6000 to spare I'd have the other. All I can say is that I concur with you on Line Magnetic they certainly seem to have got it right I have heard a fair number of their amps being a friend of the local importer. When ever he gets a new one in I get to listen. I myself have the entry level 211IA and it is a very good amp. I also happen to be a friend of the local Ming Da importer, and he gave me a good selection of Ming Da amps to take home and try on my system; another friend and myself had a great Saturday and Sunday giving the Ming Da's a bash. Verdict the little Line Magnetic was significantly better than any of the Ming Da's, the kicker was the Ming Da's were in some cases 10 times the price. I have included a link to his site for interest sake, so you can check out the Ming Da's. We tried out most of them including the SET's. Just search Ming Da. Also check out his other drool goodies. Audio Exchange | High End, Hifi, Buy, Sell, Sale, Naim, Sonus Faber ...
<cite class="iUh30">https://www.audioexchange.co.za/</cite>
Thanks for the link. When Ming Da first appeared here in the UK, I had a fleeting fancy, but couldn't afford any. Years later I got their first phono amp. I got it cheap as someone had tried to modify it. Looking on the internet I found many complaining that it was weak in the lower registers. Someone measured it an found it to be 6dB (I think) down, which would explain it. Some tried to modify it, with no real success, and others ended up just using it as a base for another design. I never got round to doing anything with it. Could you say what the price is locally for the LM 508ia? The price for one into the UK varies wildly from €5,500 ($6,200), to $2,400 (plus customs duty). Apart from the initial cost, the only disincentive is the cost of replacement valves. Would love the 805. Was thinking that the 4 805s were used as parallel pairs on the output. Discovered yesterday, that 2 are actually used as rectifiers. Will have a look for your amp. Always fancied a 211 or an 813 design. Thanks. |
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Deleted
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Post by Deleted on Feb 11, 2019 20:00:41 GMT
Unfortunately there is no official UK dealer
Europe is catered for by dealer's in France and the Netherlands.
Shame .....
Please be aware there are apparently fakes oot there, and also be aware that if you don't purchase from an official LM dealership.
Your on to plumbs if let goes wrong.
Apparently the genuine items have battleship build quality and are all point to point hand wired and use quality components.....Never read a bad review of em.
I did try hard to secure the LM211A as recommended by lemons but it didnt work out
Shame as it uses me favourite valves el34's.
This left me no option really but to order a Radford STA25 which incidentally (6 months later) im still waiting for......no hum.
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Deleted
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Post by Deleted on Feb 11, 2019 20:19:51 GMT
Price in South Africa for the Line Magnetic 508IA from SA agent is the $USD price converted to the current $USD to SA Rand exchange at time of order payment. $5000 new, works out at today's exchange rate = R69,000 = 3,382 British pounds. Be careful stay with the official agents. Sellers in Hong Kong sell second hand as new.
The 211IA is an EL34-6CA7 amp 32 Wpc Ultra linear 12 Wpc Triode. I paid equivalent of 730 pounds for the 211IA new from the agent in 2013, a bargain to be sure.
Not a moments hassle still running original valves. Not One Line Magnetic sold in this country sourced from the official agents has ever given any problems.
The same cannot be said for the ones brought in direct, there have been some damaged in shipping, dinged, broken valves, and one that I know of that needed some attention. Second hand?
Always personally preferred the sound of an EL 34 amp in triode to an SET amp, Better all rounder, and they just have more drive than an SET when it comes to the heavy stuff. Plus valves are as cheap as chips and last for ages.
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Deleted
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Post by Deleted on Feb 11, 2019 20:23:51 GMT
Unfortunately there is no official UK dealer Europe is catered for by dealer's in France and the Netherlands. Shame ..... Please be aware there are apparently fakes oot there, and also be aware that if you don't purchase from an official LM dealership. Your on to plumbs if let goes wrong. Apparently the genuine items have battleship build quality and are all point to point hand wired and use quality components.....Never read a bad review of em. I did try hard to secure the LM211A as recommended by lemons but it didnt work out Shame as it uses me favourite valves el34's. This left me no option really but to order a Radford STA25 which incidentally (6 months later) im still waiting for......no hum. Might as well of hang on and got the LM Jammy. I also see now why you did not want to put up pics, waiting for the Radford and all  |
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Post by Deleted on Feb 11, 2019 20:27:39 GMT
System pics to follow lemos as soon as the Radford arrives. Aye 6 months and counting is a fare waiting list but Will assures me things are progressing nicely. It's one of these four....  via Imgflip Meme Generator😁😉😁 |
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Post by sq225917 on Feb 11, 2019 20:53:39 GMT
Will does insanely good work, truly meticulous
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Deleted
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Post by Deleted on Feb 12, 2019 1:01:53 GMT
Price in South Africa for the Line Magnetic 508IA from SA agent is the $USD price converted to the current $USD to SA Rand exchange at time of order payment. $5000 new, works out at today's exchange rate = R69,000 = 3,382 British pounds. Be careful stay with the official agents. Sellers in Hong Kong sell second hand as new. The 211IA is an EL34-6CA7 amp 32 Wpc Ultra linear 12 Wpc Triode. I paid equivalent of 730 pounds for the 211IA new from the agent in 2013, a bargain to be sure. Not a moments hassle still running original valves. Not One Line Magnetic sold in this country sourced from the official agents has ever given any problems. The same cannot be said for the ones brought in direct, there have been some damaged in shipping, dinged, broken valves, and one that I know of that needed some attention. Second hand? Always personally preferred the sound of an EL 34 amp in triode to an SET amp, Better all rounder, and they just have more drive than an SET when it comes to the heavy stuff. Plus valves are as cheap as chips and last for ages. Thanks for that. Sorry. Forgot your location until after I posted. For some reason had it in my head you were in the US, hense to $ prices. Had a look on the LM website and it does mentions counterfeits and a few sites to avoid (AliExpress). I suppose the cheap ones I found will be the copies. Might just have to stick with my Yamaha P2200. From the name, I thought your amp had 211s in it. After a search saw that it doesn't. The price you give for the 508ia is lower than some European dealers. |
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Post by Deleted on Feb 19, 2019 2:41:48 GMT
Having designed and built hundreds of amplifiers over decades... I don't know! But it's certainly not the things most audiophiles believe to be important... like power supplies... within reason anyway. I'm assuming power amps here BTW.
An amp that measures bad will sound bad but an amp that measures fantastically good may not sound particularly good.
Decent open loop linearity is a good start.
Wide open loop bandwidth always seems instinctively right and is something I aim for even though I know that ultimately it's not a game changer... Many amps are only flat from say 20Hz to 100Hz (not a typo) open loop and the average op amp from DC to about 5Hz.. yes 5Hz... the gain starts to fall off that soon. Good thing there's loads of it to play with... like X 10,000,000 for many op amps..
The frequency compensation is very important to both the measured performance and the subjective sound (and the amp will blow up on switch on if it's nowhere near right!). There should be more than adequate gain/phase margin to allow unconditional stability without getting anywhere near the Barkhausen criterion... Yes Naim I'm looking accusingly at you!
I like the bass to go down to a few Hz or less for best low end performance (way below the lowest audible frequencies). Amps that only go down to 20Hz ish just don't sound right in the bass to me.
At the top end I'd be pretty suspicious of any SS amp that couldn't make a good stab at reproducing 100KHz when any input low pass filter (LPF) was removed.
Class A is a huge advantage in every measurable parameter.. but at a hell of a cost! It is not the universal panacea though and an "average" class A amp may well not sound as good as a really superb class A/B amp. It's a fantastic foundation to build on though (the best)! A class A amp will unfortunately be maybe 10 x more expensive in component costs per Watt...
Negative feedback (NFB)... a real can of worms! All the open loop/closed loop stuff above refers to the NFB loop BTW. This is the universal panacea of measured performance. EVERYTHING (other than stability!) gets better in proportion to how much feedback is applied.. up until "the engines cannae take it captain!" and it becomes unstable and often goes bang. Loads of NFB is how we get amps with 0.001% THD and damping factor of 1000. Without it many SS amps may be as bad as FR of 100Hz - 8KHz and distortion of 5-20%! Typically a valve amp would use about 20dB NFB (x 10) and a SS amp maybe 60dB (x 1000) (the output transformer in a valve amp prevents more being used and this is why valve amps generally measure much worse than SS amps... it's nothing to do with the valves themselves!).
Unfortunately, for reasons we can't yet explain, lots of NFB often, but not always, results in that grey, sterile, edgy sound we have all heard from some SS amps...
Best practice in the grounding and layout of the amp is also very important ie lots of things connect to ground or power supply but where and how they are connected is critical!
And here is where I have to be "nasty Jez" and say that if that's all gobbledegook to you and you think it's down to the brand of the capacitors, the type of wire and the weight of the mains transformer etc etc you have much to learn grasshopper!
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Post by firebottle on Feb 19, 2019 7:47:35 GMT
I like it Jez. Even 'nasty Jez'  I would describe the sound of excessive NFB as 'sat on', even feedback RIAA stages lose a little of the dynamics to my ears. I am convinced that different film/construction capacitors have an influence on the sound. There isn't a one size fits all though, I think it depends on the actual circuit impedances, applied voltage and signal level for each position. |
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Post by sq225917 on Feb 19, 2019 8:02:07 GMT
Caps are like any other part, you have to choose an adequately specified part for the task at hand, but tales of their huge audibility are massively overplayed. Sure, feedback caps are pretty audible, probably followed by PSU caps and lastly crossover caps. I struggle with the thought that every cap in every position in an amp is audible. I've completely recapped gear before, 100+ caps and the sound didn't change at all.
There's some super sterile SS stuff out there with plenty of NFB in the mix, but similarly there's plenty of good SS stuff with bags full of NFB that doesn't sound like that.
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Post by firebottle on Feb 19, 2019 8:26:16 GMT
I know, it's all very confusing. I never said every cap position is audible btw. All about circuit implementation. |
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Post by dsjr on Feb 19, 2019 9:48:21 GMT
A good amp is one that's happy with the load it's driving if the rest of it has been competently done imo. Most other factors were 'sorted' decades ago I also believe. I believe the reason why Krells costed so much is the power supplies and casework (to take the heat from the overbiased circuit as expected from their market, which wanted a largely Class A bias) to allow these amps to drive the late 80's fashionable 2 ohm ribbon speakers that the audiophile market become besotted with for a while. Those that 'knew' back then bought Levinson instead, but because Colloms (apparently) fecked up a Levinson review due to badly calibrated test gear (apparently), HFN never got to review these products which is why Krell alone is revered in the UK at least. My Crown D-150 for example, isperfectly happy driving my current speakers without stress, so *in this system* it sounds exactly the same as the Krell did. Give it an awkward load and it deliberately falls to pieces as designed, protecting itself. Looks and nostalgia aside, I'm not sure of the point of valve amps today, but I'll keep custodianship of the Quad II's I was entrusted to, which can process the sound so nicely when in use. |
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Post by Deleted on Feb 19, 2019 12:45:36 GMT
There are a few positions in certain types of amps where the capacitor can make very noticeable changes but by and large they are much of a muchness. Try making up a crude test by allowing a capacitor to be placed in line between pre and power for example and be stunned at how little difference there actually is even between a 10p electrolytic and some £30 boutique film cap! I did just such an experiment about 25 years ago (when no doubt my hearing would have been more acute than at 54!) and the difference between 10p electrolytic and top quality polypropylene was audible but only just. Once using anything better than an electrolytic I couldn't tell any difference.
Personally I have no problem with feedback RIAA. Feedback seems to adversely effect power amps more than anything else IME. Sadly this is where it's most needed!
I don't see driving difficult loads as an issue at all. You just throw a bit of money at the problem and it disappears...
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