Bigman80
Grandmaster
AA Founding Member & Bigbottle Audio Creator
Posts: 16,358
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Post by Bigman80 on May 31, 2019 4:14:03 GMT
Worth a go Oli, tell you what, give it a few weeks and I’ll post them down to you to try. You're a gentlenan Ali, it's much appreciated I'd post the Krell up but......  |
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Deleted
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Post by Deleted on May 31, 2019 5:30:32 GMT
You're a gentlenan Ali, it's much appreciated I'd post the Krell up but...... He's making that look too easy lol |
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Post by dsjr on May 31, 2019 11:41:39 GMT
Progress I guess. I’d still have a Krell though lol. Only if you can service the effin' things  |
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Post by dsjr on May 31, 2019 11:50:37 GMT
...but the 4367 is delightful in a kind of full bodied but very clear and easy kind of way. Very old-school in the best sense. Better than my revered ATC 100ASL's? Not sure really - I'd have either given the room and finances. The JBL's obviously allow choice of partnering gear where the ATC's are journey's end really... I didn't hear the 4367's for long, but when I did I fell in love with them (Buddy Holly singing 'Every Day')
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Post by macca on May 31, 2019 12:01:18 GMT
I think they will be at the Cranage show next month, bit far for you to travel though.
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Post by dsjr on May 31, 2019 12:05:14 GMT
I was saying yesterday to fellow HFS forumites. I'm skint and desperately need to flog some stuff now. It's all very well hearing once again, products like this, but size and price is way off, even at best trade prices (I still have friends around and about and know the importer). Best I don't make myself more miserable than I am currently...
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Post by macca on May 31, 2019 12:31:14 GMT
There's nothing at that show I can afford either! Except maybe some MCRU trinkets. It's still a good day out though. Beautiful location, very classy hotel, good rooms for the most part and lots of interesting exhibits.
Ollie are you going to go? It's at the end of June.
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Post by alit on May 31, 2019 13:36:54 GMT
Progress I guess. I’d still have a Krell though lol. Only if you can service the effin' things Pretty sure I could figure it out. :-) |
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Post by Deleted on May 31, 2019 13:46:08 GMT
Only if you can service the effin' things Pretty sure I could figure it out. :-) Anyone would think its made of some sort of cryptic magic. I can navigate it OK, even replaced a few caps myself. If I can do it, anyone can. |
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Post by Deleted on May 31, 2019 13:48:56 GMT
There's nothing at that show I can afford either! Except maybe some MCRU trinkets. It's still a good day out though. Beautiful location, very classy hotel, good rooms for the most part and lots of interesting exhibits. Ollie are you going to go? It's at the end of June. It's a possibility. I'd need to look at my roster for work and then get a pass off the wife lol |
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Post by dsjr on May 31, 2019 14:02:06 GMT
Your Krell is NOTHING like the one macca has, let alone the FPB models. Sure the circuit has an input stage, V/I conversion, a driver and output stage, but I believe the complexity around these later models is something else, especially as regards the plateau biasing, soft start side and so on. I only ever lifted the top cover and took a couple of pics of a typical 120VA transformer compared to the 'baby Krell' one (macca has the pics and posted them once I think), but I admit I would be Sh#t scared of dismantling it as has apparently been done. For an experienced engineer, it's not too huge an issue. Dan D'Agostino, after the success of the 50 and 100 amps, went the design route of having a current amp from input to output (hence the rows of input transistors biased quite 'hot' I believe) and then went fully balanced in-to-out in the generations which followed. Loads more components in the signal path and maybe by this time, not added distortion as components were much better by this time and no need to skimp on component costs as Naim did back then, as the selling price wasn't really an issue. I suppose my current amp disciplines tend to ever simple circuits and the old Crown 'D' series I normally use actually has a simple audio signal path bar the input op-amp and the rest of it is mainly the individual regulated supplies for each gain block and the feed-forward circuits for the output (it's an earlier form of the current dumping circuit I believe, but not quite the same - better as it's not as critical nor as distortion prone imo). If you want to look and take me to task on the stuff I've just typed, look on the Harman/Crown reference site as circuits and manuals for these old amps are all there to download for nothing and Ken Rockwell has done modern tests on the D-150Amk2, D-75 original and the tarted up PL1, which was Crown's better looking swan-song range before abandoning the domestic market to the audiophool fate it's suffered since...
In the late 90's, Krell made the simpler but heavily output transistored KAV 250 power amp. I found it a tinny sound (could be the Kimber and Siltech cables we used) and it had NO output protection apart from a line fuse which blew with a flash along with half the output stage as soon as it sensed an accidental short on the speaker terminals! I speak from deep experience here - cough.....
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Post by macca on May 31, 2019 16:44:59 GMT
I e-mailed Krell to see if they would send me a schematic for the KSA50s. Didn't really expect to get a response. I mean they haven't made them in 25 years.
Twenty minutes later - they sent me a full schematic, pages of it. You could build one from scratch from it. Can't fault that for customer service.
Hopefully means fixing it will now be no problem.
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Post by dsjr on May 31, 2019 18:15:59 GMT
That's great  I know the original circuit is on the web but not the 50S and family that I could see. I'm not bloody criticising it ffs chaps, but for my use it was too good at driving speaker loads I didn't have, too hot running *here* (I didn't realise I was such a head-banger but the speakers are around 84 - 85db sensitivity) and I just couldn't face the prospect of re-capping it as and when the time came. Ramble alert... I've been reading the 1987 'Choice amps book. Effing 'ell, the 'care' in wording stuff is ridiculous and Colloms was at the beginning of his 'guru/consultant' era and i felt his ego was expanding year on year, to peak in the late 90's onwards. The KSA50 is great and top of the tree BUT, the KSA 100 is better BUT, the 50/100 mk2 are better again and of course the KMA 100's are out of the field completely, they're so good, mk1 or mk2!!! (I can scan the review if you're interested but not sure how to post it). |
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Deleted
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Post by Deleted on May 31, 2019 18:38:06 GMT
Genuine 50 clones have been built since 2004 over on DIY Audio.
There's a 510 page thread
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Post by macca on Jun 12, 2019 16:54:47 GMT
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Bigman80
Grandmaster
AA Founding Member & Bigbottle Audio Creator
Posts: 16,358
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Post by Bigman80 on Jun 12, 2019 17:12:16 GMT
I had an original 1980s PMA250 but it lost out to a Rotel RA840 BX2. That blew up and was replaced by a Cyrus One. Is this a much later model? It’s so long ago, I’ve forgotten what mine looked like. I worked for Richer at the time and I got a few amps that lasted a week or so before being replaced. |
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Post by macca on Jun 12, 2019 17:33:27 GMT
No this is the mark one, from the mid-late 1980s. They did a 250, 250SE and a 250UKSE. And the same in the 350 range too.
The Mk2 range came out early 1990s and was not as good imo and I've had both. Mk2 is more bassy but lost the sweet and open mid top. Mk2 looks like it should be better, looks much more expensive, is heavier, has a better quality case, proper silver=trim feet and more sophisticated graphics. But it didn't have the magic.
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Post by macca on Jun 12, 2019 17:41:40 GMT
With my old one I had the best-sounding system I've ever had until recent years.
Systemdek IIX, Linn Basik Plus, Nagaoka MP30, Denon PMA250UKSE, Wharfedale CRS3 on sand filled Apollo stands. But the Denon went faulty on one channel so I bought a brand new Mk2 to replace it and it really was not much cop. Sold that and got a Trio/Kenwood receiver. That was average at best so got replaced with a Cambridge P70 which I used for years.
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Deleted
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Post by Deleted on Jun 12, 2019 17:45:47 GMT
I know Geoff (Walpurgis) highly rates the 1990's era - Denon PMA-350SE.
S.
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Post by macca on Jun 12, 2019 18:01:54 GMT
Yeah Geoff rates the later ones which I don't really agree with him on. They are competent amps and they can be bought pretty cheap, and the 350 is not bothered about driving tough speaker loads. But I think only the mark ones sounded 'special'.
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Post by dsjr on Jun 12, 2019 18:22:48 GMT
I think my experience twenty years ago was with the mk2's? 250se lacked power on dem (maybe just fine at home for most) and the 350se was great value (probably mk2 as I said). Does anyone remember the 450se? Measured out at nearly 100WPC I remember, musical if a touch exuberant. Sold for around £250 twenty odd years ago.
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Post by macca on Jun 12, 2019 18:59:31 GMT
The 250 is only 25 watts I think. I remember the 450SE but never had a go on one. I think it was more than £250 though. IIRC the 350 was £250 in about 1990. But I could be wrong.
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Post by antonio on Jun 13, 2019 4:40:29 GMT
Nostalgia is a thing of the past.  |
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Post by macca on Jun 13, 2019 7:15:03 GMT
We'll see. It's fifty-quid punt, what's the worst that can happen? |
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Post by Deleted on Jun 13, 2019 7:58:44 GMT
We'll see. It's fifty-quid punt, what's the worst that can happen? Paid the same for the 350SE currently in my spares rack, found it very bland.  |
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Post by macca on Jun 13, 2019 11:17:30 GMT
But that's one of the later ones. Check the difference in appearance between that and the one I've bought. The later ones are nowt special.
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Deleted
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Post by Deleted on Jun 13, 2019 11:23:21 GMT
We'll see. It's fifty-quid punt, what's the worst that can happen? The mains could short to earth with no earth connection at the plug, and toast you at switch-on. I think that's probably the worst that could happen. |
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Post by macca on Jun 13, 2019 11:45:41 GMT
I was think more along the lines of the case being contaminated with a deadly disease that has a 24 hour incubation time, so by the time I get sick the rest of the world has already been infected.
But you're right I could also get electrocuted to death.
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Post by macca on Jun 14, 2019 17:15:55 GMT
Was hoping that Denon might turn up today but it didn't. Too used to buying off forums where stuff turns up the next day most of the time.
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Deleted
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Post by Deleted on Jun 14, 2019 17:36:22 GMT
Some good reviews under the Ebay listing including this one  |
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I know the original circuit is on the web but not the 50S and family that I could see. I'm not bloody criticising it ffs chaps, but for my use it was too good at driving speaker loads I didn't have, too hot running *here* (I didn't realise I was such a head-banger but the speakers are around 84 - 85db sensitivity) and I just couldn't face the prospect of re-capping it as and when the time came. 
