i'm on a roll... the kgsshv

[Beefy]

Percy claims to have balanced CP-2511 for $76, but that doesn't make sense considering the stereo is $72.

Maybe a typo for $176?

[spritzer]

I have plenty of the Alpha pots so feel free to PM me . Same goes for anybody looking for a good 4-gang pot.

[justin]

Percy claims to have balanced CP-2511 for $76, but that doesn't make sense considering the stereo is $72.

Maybe a typo for $176?

based on what i was quoted in Qty of 100, i'd guarantee it's a typo, and think the stereo price is very low unless he's just trying to clear stock

[Beefy]

based on what i was quoted in Qty of 100, i'd guarantee it's a typo, and think the stereo price is very low unless he's just trying to clear stock

Partsconnexion also has the 2CP-2511 for $72. I ordered one just yesterday for my Crack.

[kevin gilmore]

Now i find the stth1512 rectifiers are no longer available in a to220 package, or order time is a year...

Need 1200 volt 8 to 15 amp ultra fast rectifiers in a to220 package... In stock...

[jgazal]

Now i find the stth1512 rectifiers are no longer available in a to220 package, or order time is a year...

Need 1200 volt 8 to 15 amp ultra fast rectifiers in a to220 package... In stock...

Ixys DSEP12-12B, TO-220AC, 35ns, 1200V, 12 amps (Mouser 747-DSEP12-12B)?

[Craig Sawyers]

Partsconnexion also has the 2CP-2511 for $72. I ordered one just yesterday for my Crack.

I moved off TKD because there is not a good electrical connection between the shaft and collar. The net effect is that you get a crackling or whooshing sound as you turn the shaft. Mine was so bad that I returned it for a replacement - which was exactly the same. Eventually bought a DACT from Justin, which is a sonic source of joy. Somewhere lurking aound in the head case threads is talk of dismantling the TKD and putting silver loaded grease on the shaft to get a better connection.....

My TKD sits in the spares box, and might possibly be used in some other, non-audio project eventually. An expensive addition to the spares box....

[Beefy]

Yeah, I read that before I purchased, but I don't think it will be a problem for me. I rarely sit and play with the volume while I listen......

Seriously though, I would consider steppers, but I listen at such low volumes that fine control of volume would be non-existent.

[luvdunhill]

ISL9R8120P2_Q Fairchild Semiconductor Rectifiers

I'm not exactly sure what the replacement part will be, but nice devices.

If you want something exotic, I'd recommend the SiC devices:

Digi-Key - C2D05120A-ND (Manufacturer - C2D05120A)

[justin]

I moved off TKD because there is not a good electrical connection between the shaft and collar. The net effect is that you get a crackling or whooshing sound as you turn the shaft. Mine was so bad that I returned it for a replacement - which was exactly the same. Eventually bought a DACT from Justin, which is a sonic source of joy. Somewhere lurking aound in the head case threads is talk of dismantling the TKD and putting silver loaded grease on the shaft to get a better connection.....

My TKD sits in the spares box, and might possibly be used in some other, non-audio project eventually. An expensive addition to the spares box....

can i check this part out? i had been hoping to find a quad pot that is better than the RK27, much cheaper than the RK50, and PCB mountable. and if a stepped attenuator, way more steps than the DACT.

[kevin gilmore]

Ixys DSEP12-12B, TO-220AC, 35ns, 1200V, 12 amps (Mouser 747-DSEP12-12B)?

Yep, that works. Slightly more expensive, but ok.

The prices on the cree diodes is just plain silly.

[Pars]

Percy claims to have balanced CP-2511 for $76, but that doesn't make sense considering the stereo is $72.

Maybe a typo for $176?

That is a balance pot, not balanced.

I moved off TKD because there is not a good electrical connection between the shaft and collar. The net effect is that you get a crackling or whooshing sound as you turn the shaft. Mine was so bad that I returned it for a replacement - which was exactly the same. Eventually bought a DACT from Justin, which is a sonic source of joy. Somewhere lurking aound in the head case threads is talk of dismantling the TKD and putting silver loaded grease on the shaft to get a better connection.....

My TKD sits in the spares box, and might possibly be used in some other, non-audio project eventually. An expensive addition to the spares box....

Percy recommends using silver conductive grease on the shaft to rectify this. It works, but the grease is kinda pricey.

[wink]

My Khozmo showed up yesterday. ordered last month.

The steps are more firm amd pronounced than the DACT.

[ATTACH=CONFIG]3711[/ATTACH]

[Beefy]

That is a balance pot, not balanced.

Ah, thanks for the correction!

[ujamerstand]

I moved off TKD because there is not a good electrical connection between the shaft and collar. The net effect is that you get a crackling or whooshing sound as you turn the shaft.

That's something I would expect from a RK27, not something as expensive as the TKD pots. I don't think I would sit around to play with the volume either but I can imagine it would annoy the hell out of me when I do turn the pot. How does the alpha pot fare with this regard?

[spritzer]

I've never had any noise issues with either the Alpha's or the TKD's, either the 2500 or 601 series.

[wink]

parts connexion now carry khozmo attenuators, but they don't carry the 50k quad.

https://www.partsconnexion.com/conrtols_attenuator_khozmo.html

[Kerry]

Now i find the stth1512 rectifiers are no longer available in a to220 package, or order time is a year...

Need 1200 volt 8 to 15 amp ultra fast rectifiers in a to220 package... In stock...

Newark has a few (about 30) just to test with.

[qusp]

based on what i was quoted in Qty of 100, i'd guarantee it's a typo, and think the stereo price is very low unless he's just trying to clear stock

nah i'd say the stereo price is legit. he has very good prices on his pots and rotary switches; along with a few other things. cant see how the 4 gang could be right though, unless hes doing some sort of clearance.

[qusp]

KG, yep linear is doing some of the most amazing stuff in this area I have seen. the active current source controllers are particularly interesting. difficult to find around the place, but you can buy direct even in small quantities AFAIK and farnell carries a chunk of it (albeit at the usual farnell inflated prices) they have a fairly generous samples policy also

in fact they seem to be revolutionizing this whole area. below will source/sink +/-500ma, but you can use this in conjunction with mosfets to boost current capability. very interesting device. I toyed with the idea of and may still pursue, using this in place of a TLE2426 rail splitter in my portable dac/amp (portable buffalo II), so instead of buffering a Vground reference, use this to truly actively control the sourcing and sinking of current in a floating bipolar battery supply. In effect this thing BECOMES the ground channel; with only a few external components and not much in the way of power consumption. Currently i'm just using a plain old center tapped 4 cell and 6 cell A123 lifepo4 battery pack (these things are so good, anything I add after them will fall short), so I dont want for current, but this thing is still on the radar as its just so cool.

linear are the kings of battery management, insanely low noise LDOs and just generally kicking ass in forward thinking power supply devices IMO. I was blown away with how completely their stuff integrates, but you really dont see their stuff used as often as you would think in audio, but i'm sure their defense contracts are substantial

1970fb current sink-source.pdf

[qusp]

sorry if the above sounds like an ad, I have no affiliation and the gear i'm working on is just DIY for personal use, but I think it worth mentioning as it seems it fits quite well and I dont see their gear used all that much in our particular area of endeavor

I tried to combine this in the above post, but was too late, any mods feel free

[kevin gilmore]

I'm pretty sure i'm done with the power supply, schematics and board layout updated.

Tests indicate about 12 microvolts of noise at full power. Its when the diodes turn on, and

using the 35ns soft recovery diodes, even ceramic caps across them make no difference.

Over the range 10C to 50C and under full load the power supply voltage changes only 1.2 volts.

Measuring this is not at all easy. So i'll call it a better than -140db power supply and be done with.

http://gilmore.chem.northwestern.edu/kgsshvpower3.pdf

spacers added to the non-insulated parts, update in a few minutes.

http://gilmore.chem.northwestern.edu/kgsshvps7c.jpg

also dual cap sizes for spritzer, and heatsinks for luvdunhill

Edited September 25, 2010 by kevin gilmore

[luvdunhill]

nice.

I'm doing some tests now with soft recovery diodes. I've found that with soft recovery, a C doesn't really do anything. Perhaps try 100 ohm with say 100nF in series across each diode (so, RC across each).. I've even been playing with a (RC || R) arrangement as well, and even adding a RC across the secondary in addition.

[kevin gilmore]

Tried a number of the C,RC,LRC,.... Which resulted in magic smoke and parts flying across the room.

Inductors are a bad bad thing.

By the time you are at microvolt levels nothing works.

Now if i wanted to double the size of the power supply, i could bandpass filter the noise peaks,

invert with an ultra low noise amplifier, and add it back in to the output signal, canceling out the

spikes. At which point you would still have about 1 microvolt of thermal and shot noise.

The amplifier has 50 to 60db of power supply rejection anyway.

Even if you piled up a large stack of car batteries, the resulting noise would be more than

10 microvolts.

Edited September 25, 2010 by kevin gilmore

[luvdunhill]

strange, never had any smoke. yeah, inductors are bad. any inductive resistors are bad. In fact, carbon comp resistors seem to be best. Anyways, lots of tweaking potential here. For example, I bet Kerry could really improve his supply by adding a RC on the secondary to help with the cap recharging noise you pointed out. Haven't tried the 10uF cap on the mains side that John Curl seems to think is necessary, but soon enough.