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Old 13th September 2013, 02:06 PM   #81
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Join Date: Mar 2007
Location: Oxfordshire
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This is a great idea that isn't . The Valhalla will happily run on a 320V DC supply or battery . As a DC supply has mains ripple that is of small advantage . Here the idea is to charge capacitors with a relay . The Valhalla supposedly never sees the mains . Well if does as the graphs prove . I could totally isolate by not having the - VE direct connected and two extra relays . This has proved the improvements are at a conclusion . Do not try this at home , very dangerous . The discharge curve is to help me calculate the best switching time . I used 253 V so as to have the greatest chance of success . The DC must not go below 295V or about 87% ( 0.87 ) . 10 seconds is correct for my Valhalla , normal Valhalla discharges quicker .

If wondering this was about checking out Linn's claims . I had a Lingo . I suspect before nearly anyone else in the world ? I was never totally convinced about is being better although certainly more refined . My feeling is the hum can be dealt with easily and is a part of a 45 RPM modification worth doing . It must also help 33 1/3 . My No 1 turntable is a Garrard 401 with Nam Aro . This is in Germany . This bit of fun will get the LP12 back into use , I guess anyone can see I wanted to do this for my own use . I have a hunch it will be very OK . Next to make my own chassis I think .
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Old 15th September 2013, 11:57 AM   #82
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Look how much the Valhalla needs to float . Metal behind it bad . Take that metal to ground for the worse ( like an LP12 ) . Same improved circuit in each ( 220 uF ) .A wood box seems best . LP 12 might do well with a Paxolin ( Phenolic paper ) strut to replace the metal . Still earth the black bolts as usual . 33 1/3 is not so bad because at least the hum is at the same frequency more or less . In 60 Hz countries debatable . Plywood if no Paxolin . Copy the LP12 metal piece . Paxolin chassis would be an excellent idea . Logic turntables tried one . Might rival the new upgrade ?
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Old 16th September 2013, 11:49 AM   #83
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Very unhappy over my discovery I set about a simple solution . I add other ideas because people pontificated too easily . One of these would be external DC . Mostly it makes it worse ! . When better it is technically dangerous . I would advise a transformer for those wanting this up grade . The problem is simply the LM324 op amp Linn use is unhappy on a two wire PSU . It needs three wires ( + 0 - ) . Neutral and Ground are almost the same wire . This allows very little common mode rejection . Strangely what would be suspected to work makes it worse in most cases . It is Earth ( GROUND ) - Neutral related . DC + no GROUND is a NO-NO ( shame as it is working very well ) .

THE GOOD NEWS .The solution turns out to be very cheap . I am using 12.5 MM x 4 mm nylon stand-offs . This puts valuable extra space between Valhalla and the chassis brace / Valhalla support . Only 3 dB off of what Jay has in an external Valhalla . My 220 uF caps are about 22 mm diameter . Later this week thus will be installed , I will see if larger stand-offs are possible ( longer = better ) .

This is my friends present . It has to be right .
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Old 16th September 2013, 05:35 PM   #84
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Sorry about photo quality .

Output control gives 66 to 86 V rms red phase ( as did Lingo prototype I was told ) . Yellow and white wires go into the PSU and soldered to R13 .

Red is always on and says 33 1 /3 . Blue in addition 45 .

12 v + does not go to a Valhalla pin . I added it ( 1 mm VERO pin ) . It goes via 130 R to vacated R3 hole . R2 and R3 68 K . These do not get hot . Mostly this is a mod for engineers .

The DIN assists setting up LP12 as it makes removing parts easier .

The 0V is using the unused Valhalla terminal .

Relay runs on - 12 V and + finds 0V on PCB .

Finished . Happy Christmas Malcolm .
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Old 25th September 2013, 04:28 PM   #85
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Christmas present installed and LVV lift lower fitted to his Ittok ( LVII mk 2 + Troika , still working great ) . It just about clears using the Ittok rubber platform . Mr Ito added a shot that fits a treat . The original died years ago . It clears the weight dial by about 2 mm . Not a problem really .

The new Valhalla sounds better ( 50 % ? perhaps greater ) . Less mechanical and very sweet without being soft . Less one note bass ( Linn chassis resonance circa 25 Hz ) . In fact brighter without harshness . We used 80 V rms 33 1/3 and 90 V rms 45 . It starts at 45 a treat . It is an LP 12 , a better one . Not as good as Linn's Keel upgrade but in that direction . To my ears better than an early Lingo .

The capacitors did force the bottom down a bit . Two wood screws cured that . I am sure there will be ones that fit better . If not make a DC box and house it externally ( cheap and good ) .
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Old 25th September 2013, 04:48 PM   #86
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GreenStreet Audio

I must say what is said here I feel unable to endorse . However I see the main things have been done . Fast soft recovery diodes are good because they don't dump RFI back into the mains ( less anyway ) . If Eithernet over mains wasn't around it might be worth the effort . As for their capacitors ( same make I used , i.e . cheap ) having less ripple that is nonsense . The uF determines that . I found 220 uF to be optimum . No mention of floating supply working better . Sad to do a good job then let a wordsmith say how it works .
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Old 26th September 2013, 02:51 PM   #87
Jay1234 is offline Jay1234  United Kingdom
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Location: Way up North, In Newcastle haven't seen the Sun for days
Now that Im back from the land of wonderful & I might ad cheep coffee.
I thought it time to order the parts for the Valhalla upgrade.

Oh dear.... with a min order of 50 for the caps the total came to 94.30p thats without the relay, switch or psu thats a bit steep by any standards for a half dozen or so components.
Jay
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Old 27th September 2013, 11:17 AM   #88
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Jay . If Rapid they wouldn't want that . I am busy toady I will do a search when I can .

BTW 220 uF 200 V is acceptable . Linn sometimes used 200 V 47 uF . 250 V gives better life . I think CPC or RS had them in axial as Linn used .

http://uk.rs-online.com/web/p/alumin...633D4E4F4E4526

Last edited by nigel pearson; 27th September 2013 at 11:20 AM.
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Old 27th September 2013, 01:45 PM   #89
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This is a perfect fit for those who have the Valhalla in the standard place . Being radial and the original axial an insulated extension wire is required to one connection per capacitor .
Buy Aluminium Capacitors Al Capacitor KXJ 250V 220uF 16x35.5 Nippon Chemi-Con EKXJ251ELL221MLP1S online from RS for next day delivery.

This relay if buying from them ( the crystals are in multiples of 10 alas ) .

Buy Non-Latching Relays Telecom relay 2c/o 2A, 12Vdc 150mW TE Connectivity MT2-C93402 online from RS for next day delivery.

Rapid PT No
90-1408 4.43 MHz crystal
90-0135 3.2768 MHz crystal


Refer to previous posts for other part numbers and links .
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Old 27th September 2013, 05:04 PM   #90
Jay1234 is offline Jay1234  United Kingdom
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Location: Way up North, In Newcastle haven't seen the Sun for days
Have now ordered most of the parts from Rapid.
The Relay & caps I can pick up from a local ish RS during the week.

Can you suggest a 'small' Switch that i can use for the psu also from RS please.

Jay
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