Two speed Valhalla

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Valhalla mods

Be very careful when updating the Valhalla . The output voltages seem to be specific to each one . The reason being is that the voltage is set by a zener diode which will have a wide tolerance range ..

Mine measures 80V +/- 1 V under load, both legs. Measured while using an external isolation transformer for safety, using gloves, moving slowly and taking other precautions ! I don't recommend taking this measurement unless you've read up on it and know what you're doing. Very happy with 80V output, I won't try to change it.

Just upgrading the caps and the Paxolin would be fine and only take minutes. Don't bother using the two old caps ( retain the one output cap at 90 degrees to the others ) . 2 x 220 uF 250V is what the Valhalla needs .

I understand -- swap in new 220 uF caps for the large caps labeled C1 and C2 (at the rectifier end of the board). Earlier, if I understood correctly, you recommended to Jay to put a 0.6 W 180k resistor in parallel to R3 (one of the two 15k-ohm 3A resistors nearby). Not a good idea?
 
Hi Paul . The 180 K is fine . The isolation transformer even better . 80 VAC is excellent .

Here is the Armageddon clone .

Transformer from rapid Electronics UK 88-3819 110 VAC 120VA ( 126 VAC at my house on light load as UK is still 240 V often ) .

Toroidal Transformer 120va 0 55v 0 55v | Rapid Online

I have selected some caps to 0.22 uF to 1% measured ( 0.5% capacitance meter )

220nf 275v Class X2 Capacitor | Rapid Online

Just visible is a 3K 0.6 W in the black cable going to motor grey x 2 . This drops 37 VAC down to 88 VAC ( my house ) . That is just over 12 mA . The motor will be OK at full load and can work OK down to 70 VAC .

In the USA I suspect the capacitor would be 0.15 or 0.18 uF . I use class X2 variety as they are cheap and tough . These a certified for mains electricity use .

James ( Jay ) . I have included 4 x 1K 1W . Use as many as you like in series ( string of sausages ) . These replace the tiddler in the black lead . Use a connector block or something to make it neat .

The motor is very good on vibration using this combination . Treat it as a one to one Valhalla replacement .

swsGTaY.jpg
 
Approximately 1 K = 12 V AC reduction . I have a very small but adequate 3 K resistor as the test device between black and twin grey . That was giving me about 88 VAC between twin grey and red . Valhalla was about 90 VAC old days and 80 VAC later on . Even full 126 VAC is OK if you like it ( I think it will sound a bit overblown ) . Just listen and see what you like best . I have tried to make it as safe as possible . Just for it's own safety keep the resistors clear of any metal . As it is floating and isolated , plus only 120V it should be reasonably safe to hold the motor if you want to . I did and was very impressed . At 4K the heat is less than 1 watt shared between 4 ( 1K ) x 1 watt resistors ( BC high temperature ones ) . The 3K I fitted is running about 0.5watt and is a 0.6W device . Good enough for a while .

The main thing is the ones included are 1 watt which means they will not be stressed . I have a hunch this will be very OK . Try it as supplied first .

There is a spare fuse in the IEC inlet draw should you ever need it .

Off to Cornwall to see the winter sea at the Port William Inn .
 
Graham or Nigel (or others.... )

As I'm still learning my way around DIY electronics, I'd appreciate any recommendations on wiring from the external motor controller box to the TT. I've looked at Mouser and PartsExpress and the like for umbillicals, but these seem very pricey for what you get. I'd like to be able to disconnect the power supply/controller from my LP12 with relative ease, though I'll use a terminal strip underneath if need be. My modified Valhalla-motor control box will reside about a foot below the TT.

I can find some nylon braiding to cover the wires, that's easy enough. Any reason to do anything special with the wires (twist or turn) (composition/just standard copper wire?) (gauge > 22 or maybe 18?) --?

Any suggestions are welcome.
 
Hi Paul .

Jay had some bad experiences with the Valhalla . In truth I gave him about $500 research time to solve it . The outcome was it is better not to try to modify the circuit to 45 . Instead he is using a clone of the Naim PSU .

In the USA it is not a choice as 50 Hz is produced to power the motor in the Valhalla .

All you need is an insulated box with good ventilation . Wires are exactly what you would use for any domestic equipment ( 3 amp 0.5 mm 3 core intended for mains use ) . Twisting makes no difference . The very fact it is off the turntable is useful .

Miniature Free Mains Plug | Rapid Online
GW60 001 Straight Plug 16A 110V 2 Pole and Earth IP44 | Rapid Online
Straight Plug 16A 230V 2 Pole and Earth IP44 | Rapid Online

The latter is the best if available in the USA . I think the generic name is C connector for the others . The first the very best if wanting a neat design .
 
Multiple options

Hi Nigel, and Jay --

Thanks for the responses! I appreciate the links to specific components, is of immense help in making these choices.

Jay had some bad experiences with the Valhalla . In truth I gave him about $500 research time to solve it . The outcome was it is better not to try to modify the circuit to 45 ..

Nigel, if I read this thread correctly, Tkwou, Gary, you and others have reported several successes in modifying the Valhalla boards. Not to mention mods from other threads. With Jay's board, one failure. So?

At the start, these boards have a few decades on them, so there's always a potential for them to fail. I guess I'm not convinced that one failure means not to try these (and maybe other) modifications.

In fact, I have two Valhalla boards; both have been modded (by others, before me) and both need repair! When I can make the time, I will troubleshoot both, get them working, and try a 45 rpm mod on one, and the 220 uF caps + 180k Ohm resistor mod on the other. Both will be externally mounted, and I'll be able to switch from one to the other to change formats or see if the modifications are to my liking.

Isn't this what DIYaudio is about?
 
options, options.

... The Geddon clone is way better, it even gives the motor more torque & easy to install remotely as it's a lot less dangerous!
I'm still very happy with it.

Glad to hear that's a winner for you Jay!

I'm very interested... while doing these other projects, I've been gathering the parts to build a Geddon clone.....Someday!! It may have to wait a few years I'm afraid :)eek: !)...

As Nigel alluded to, the U.S. it's a bit more work, as you have to change out the TT motor. At present, I think I have all the parts I need (I have to check), including a motor with the required 17mm pulley to run a 60 Hz version; and a monster low-noise 800VA toroid transformer that I picked up off of e*bay.

Sometimes I think I have too many irons in the fire. But I love this hobby!

Since my LP12 is kaput for the moment, I purchased a budget Pro-ject TT and am continuing to enjoy my vinyl collection ! Can't be without a working turntable, may gift it to one of my kids later.
 
In case it's not obvious, the Geddon Clone I have (that Nigel made up for me) is pictured in post 122. & it is safe to use as you see it ! couldn't say that for the Val
The Linn has never sounded as good as it now does.
But then again it does now have a 40 year old Decca Blue with original stylus on it !!!!!!

Time time time what will become of me.........
 
Paul . All I know it the most off centre spring should go near the motor ( rotate about a fixed point , view the wobble of the spring , +/- 1/10 inch is common ) . Ideally this spring should be longer . If you have a dead spring that will not seem to work it should be placed front right where the arm-board says Linn Sondek . The arm cable tension can be used to stop gyration of the bounce . Don't use it to the extent it shorts out the suspension bounce . The dealer had a box of springs .to help him . None the less it should be possible to find a good bounce with any set of springs . If not the chassis is bent ( 90% I guess were to the extent it matters , 10/1000 " at a guess ) . A simple Vernier depth gauge and the sub platter will say if it is ( set the depth and see it touches evenly the chassis at all points ) . Simply make a tool to reset it . You will be surprised how easily the bearing outer moves . The tool fitted the top bearing section ( platter side ) and looked like gas pipe . Approximately 10 inches long .

All the Linn's problems come from the centre of mass being between the arm pillar and the bearing rather than at the platter centre . This was copied from the Thorens TD 150 . The Thorens TD 160 attempted a cure by placing the front spring in about 1 inch . In my opinion it made it worse although easier to manufacture . If someone placed a mass the opposite side I dare say it would help . Myself , I see the bad ways of the Linn ensure correct set up . A deck I tried where this was solved seemed not to have the rock solid sound of a Linn . I suspect it is the very difficult set up of an LP12 that ensures it works well . It is almost binary . It is possible to set up an LP12 to have the loosest bounce rather than a vertical bounce . It will sound more detailed . It will sound wrong to my ears if you do . Also a bounce that stops quickly is unlikely to sound good . Minute adjustment of arm cable is important . If taking the cable off changes the deck position it is wrong . The arm-board can be adjusted for best looks ( 3 screws ) . We used to put superglue in the screw threads to give them strength ( let it set before putting screws in , use a cocktail stick to ration the smallest amount of glue ) . The screws are very thin and strip treads in the wood easily . The setting is not just for looks . It says if the deck has gone off tune . If the arm board is slightly off centre in the hole try again to reset it . Often this was the No1 compromise . It shouldn't be drastically out . The belt needs to be on to test bounce . If the platter is up side down the belt can be checked in rotation . It should run central . This usually requires the motor to be tilted backwards slightly . The adjustment should be 1/4 turn at a time . Do one screw up and unwind the other . Getting this wrong bends the motor . I sometimes had to straighten motors on LP12's , they didn't leave the factory that way . The tilting does involve a slight bend .

The 5 mm black bolts ( zinc plate originally ) that position and hold the springs need to be vertical . The Linn tool looked wonderful and wasn't . All you need is a tight fitting tube of about 10 inches again and a spirit level with a V groove that helps set the vertical . Check it all around as what might look vertical could be 1/8 inch out . The deck has to be level if checking this . Use the plinth wood as a reference point . Not the stainless steel plate as that has a deliberate curve , A Linn jig was very useful for this . It clamped the deck and had level adjust . 90% of LP12's needed this adjusting . The flimsy fixing of the stainless steel is deliberate . Like the tyres of a car it contributes to the suspension . Don't over-tighten the bolts . If someone has , fit a new mudguard washer and re-tighten to less than 5 lbs torque ( guess ) . The wood screw Linn us at the top is to help locate the plate and needs to be sensibly tight . Matches + wood glue restore stripped threads in the wood if they have been over tightened . The hardboard bottom is OK , the risk is emphasizing the boom the LP12 has if using something high tech . Hardboard might be a better choice than armchair engineers might think . It has minimal mass and losses energy quickly . Cardboard might be better . It is fitted to offer some electrical protection .

Finally , support the spring as you rotate it top and bottom . Move it a small amount at a time. If not the setting is lost over the next day as it unwinds . Linn suggested spit as a lubricant rather than talc . Now for a drastic solution . If the deck will not bounce I have been known to stretch the motor side spring by about 1/10 inch . This would be when miles from home and asked to set up an LP12 . It always works . The thing to say is if it went wrong I took the deck with me . You will not have a box of springs as I did .

Great info, thanks!
 
Despite searching extensively, I couldn't find any information about the two Varistors V1 and V2, which are included in the latest schematic (Rev.1 , July 7, 2001) of the Valhalla PCAS 022 Motor Control PCB. http://www.turntablepsu.com/images/valhalla schematic.pdf

They seem to have been added in later revisions.
Someone said they are 150V types (MOV's) but methinks that value is a tad low.

Maybe there is someone around to have a look at such a board equipped with those varistors.

Thank you anyway.
 
I have a Linn BOM (pdf) dated 1999 for the Valhalla, so for what it's worth, the varistors are listed below:

Assembly Number: PCAS 022/L5R9 DOUBLE-SIDED VALHALLA BOARD POP.
WITH SURGE GARD & VARISTORS

...

V001 MISS 151 VARISTOR 150V 2322-594-51516

V002 MISS 151 VARISTOR 150V 2322-594-51516

....

R001 MISS 171/1 TYPE FUNCTION GENERAL INFO. C Y Y
40 OHM SG240 SURGE GARD THERMOSTOR

Internally, Linn's part number for the the varistor was "MISS 151." Perhaps the other number attached will match up to a vendor's part number, but no guarantees.

Paul
 
Found a pic !

Vishay or Philips or ? I see the same no. on other Varistors ... Orange or amber, big disc shaped units. Hopefully these are of equivalent values. I found a picture of a 1999 circuit board that has these in place. Thought you might want to see it.
 

Attachments

  • Valhalla-1999-high def pic.jpg
    Valhalla-1999-high def pic.jpg
    591.8 KB · Views: 147
Great picture Paul, yes the amber ones. These are 150V AC Varistors, so to me it's clear now.... Mouser had these, just the bigger disc (596 series) to handle more current: 2322-596-51516 Vishay / BC Components | Mouser Schweiz
The Datasheet attached there shows even the same amber colour.

Will see whether I can manage to fit them without too much hassle....the pcb is a bit different obviously.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.