Keltik mono active cards - circuit diagrams?

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poppop
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Keltik mono active cards - circuit diagrams?

Post by poppop » 2019-05-26 16:23

Hi Guys

I have seen circuit diagrams for Keilidh mono cards in the past. A mate of mine is interested in having a go at building a custom "tunebox" for Keltiks, and was wondering if anyone had access to circuit info.

Many thanks
Steve

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Re: Keltik mono active cards - circuit diagrams?

Post by sunbeamgls » 2019-05-28 10:36

It will be much quicker to buy the crossovers, possibly with a better result too.

These on ebay (I have no link to this sale):

https://www.ebay.co.uk/itm/Linn-Klimax- ... SwKUhc4awz

Not so much fun, I guess :)
AEDSM; AEBox/1; 3x Tundra Stereo 2.5; PMC 20.26. Blogger. Exakt Design. SO measuring.

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Briain
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Re: Keltik mono active cards - circuit diagrams?

Post by Briain » 2019-05-28 12:48

I still occasionally work with a chap who used to be a Linn dealer (I also occasionally worked in his Linn/Naim/Rega shop, several decades ago) and an Linn used to publish diagrams on the web site for their dealers (linfo). On that site were diagrams for everything from the Klout, onwards (though no DS diagrams) but not much before the Klout (diagrams for things like the LK1 and LK2 were drawn by hand onto bits of dead tree; I know that as back in the day, I scanned the LK diagrams into PDF format). I have just looked in my archives and though I do have the Klout diagrams, I do not have the crossover ones (which surprises me as I used to own a Klout + Keltik system, so I would have thought I'd have procured the diagrams for these bits, back in the day). As the Klout ones were drawn using a CAD package (and published as PDF files on Linfo) the crossover ones would also have been in that format, so either I didn't bother downloading them, or perhaps they were never published on the Linfo site. To be honest, I cannot recall ever seeing them (so it is possible that they were never published) though it was a very, very long time ago (I bought that system not long after the Klout and Keltik products were first released) so I could be wrong about that.

I would suggest you ask one of the 'larger' Linn dealers if they can have a look for you. I know Linn totally re-vamped their public facing web site a few years ago and I think that not long after that, they also ended Linfo, but I believe that there is a new 'dealer only' area of the web site (linked to from the main site), though whether or not they migrated the diagrams for the older stuff across, I really do not know; I'd like to hope that they did, though). If the dealer cannot find them there, perhaps they (or you, via the Linn helpline) could ask very nicely whether Linn would be willing to e-mail them to you (they're quite old products, so I cannot think why they'd be worried about disclosing them).

If you get absolutely nowhere, send me a PM (with your e-mail address) and I will send you the Klout diagrams, as though they won't contain any crossover diagrams, at least they should indicate the connections to the cards (and possibly even note the Voltages that are typically fed to them, or if not, that could probably be worked out from the diagram).

Briain

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Re: Keltik mono active cards - circuit diagrams?

Post by poppop » 2019-05-31 02:34

Hi Both

Many thanks for the replies, with apologies for the late response!

Bit of background. I had a fab Keltik set up about 10 years ago - Klimax XO's, 2 x 4200's, Akurate DS ( one of the first) Kinos.

After a long varied Hi Fi journey and unfortunately a change in "life" circumstances, Im slowly going to try venture back to where I started! I have the Keltiks, and 6 channels of non Linn amplification. An electrical engineer friend has convinced me that he will build/ modify the 20+ year old mono active cards to function better than a tunebox! Not as good as Klimax XO, but, as explained, Im no longer in a position to afford to purchase (yep, seen those on ebay, not too far from me!) I trust him and expect the end result will be v good. I still have my LP12, the one item that has stayed with me!!

That's the explanation for the need for circuit diagrams - he tells me they are not absolutely essential, but would have saved on legwork!

Briain I have tried Linn and a couple of dealers, but no joy. My guess is they are available but wont be released. I kind of get why, but I thought that as they are 20+ years old, there is no real commercial disadvantage or loss.

Im trying to work back to being a partial "old gear" Linnie! LOL

Thanks again
Steve

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Re: Keltik mono active cards - circuit diagrams?

Post by Briain » 2019-05-31 16:58

Hi

Given their age (and as you say) it rather surprises me that they wont release diagrams for them. It's also odd that I don't recall ever seeing them on the Linfo site (given how many other diagrams that were on there; many for far more recent products). I think the Kairn was the first product to have CAD drawings (and I have PDF versions of the Klout diagrams) so you'd have thought the Keltik crossovers would also have been done electronically; it is all very odd.

Incidentally, I had quite an early Klout+Keltik system and at some stage through its life, Linn redesigned the bass crossovers, though at the time, there wasn't much of a song and dance about it. I only found out about it as at that time, I was helping out in a Linn shop at the weekends (and someone from Linn told me about them) so I ordered a set up. After fitting them, I powered up the system and I initially thought I'd done something very silly as when going up close to the speakers, there was no hiss from the HF units (remember that I had not touched the treble amps; it was just the bass crossovers that I'd changed) so I then put on some quiet music and all was well. Clearly, whatever they had changed (in the bass crossovers) had somehow lowered the noise level for the entire system, so I can only assume it was some form of earth loop that they had eliminated (simply because I can think of nothing else that would cause the problem) and that it was somehow causing noise on the input side of things (thus impacting on all amps). As well as the noise floor dropping (the original system was quite noisy) the entire system also sounded significantly better, so it was well worth the effort.

I can't help but think that if it was as simple a problem as I am assuming, it's quite possible that the older type bass crossover cards could be modified to eliminate that issue (or perhaps the act of housing them in a separate box and sorting out the ground arrangements would do the same thing) but either way, I would love to have seen diagrams for both the initial and revised versions, just to see what they'd gotten wrong in the original versions (so if the diagrams had been available back then, for sure I would have downloaded them)!

Briain

PS Another 'oops' from back in the day was the Dirak (the external regulated PSU for the LK1). I had built my own (similar lines to the Dirak, but using the TO3 versions of the LM317 and LM337, a very high quality potted toroid transformer and lots of nice capacitors; it did actually sound better, too) so I was already well aware of the LK power arrangements. When the first Linn Dirak appeared in the shop, we used it to power an LK1 (which was great) then shortly after that, we got another one to power our PMS Isobarik active crossover. It arrived the day before I was working there, so being me (and to hell with serving customers) I immediately unpacked and installed it (fitting the adaptor to the Aktiv box). I fired it all up and was surprised to have serious mains hum issues (I wondered what I'd b*****ed up this time) but knowing how all that LK vintage stuff was 'laid out' internally, I soon realised what the problem was, and - after first seeking permission from the shop owner - I ended up using a scalpel to cut a PCB track (from the 0V rail to the case) within the Dirak (for the Aktiv Xover) and fitting a small capacitor, which solved the problem. Of course, we fed that information back to the factory and the issue was immediately fixed (fortunately, we tended to get stuff pretty quickly after it came out; we sometimes even got prototypes to play with). :-)

Them were the good old days; long gone, now.

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