Any recommendations as far as what supply voltage, etc. to build one for potential use with the k1000? my intention is to build the balanced version, but I'm indifferent if single-ended is sufficient for these headphones.

Not really, no.  It's well within spec. 

 

Thanks

Stick with the stock supply voltages.  No sense increasing them. 

May I know is there anymore board left for me to order?? 

Sorry to add to the broken record playlist, but do the devices/channels require some sort of matching?

Anyone can help me verify it, does the headphone jacks can be used and drive concurrent simultaneously?? If so, does it mean both channels are sharing the power to drive each one of total four drivers??

You are talking about the production amp here then?  Doesn't matter really as it is the same case with all amps that feature multiple outputs, there are just two channels in the amp so power will be shared. 

 

Sorry to add to the broken record playlist, but do the devices/channels require some sort of matching?

 

Matching is better but it should work just fine with no matching at all. 

It appears my 71-CPF3-F-2 Vishays are back ordered until October.  Is there something else recommended that I might find more expediently to act in their place?

 

Thanks.

283-2.0-RC should work just fine. 

Awesome.  Thanks.

Hello,

 

Another build in progress:

• The amp proper is built (see photos) and tested; the sound with Grado GS is wonderful! Thank you Kevin for sharing the design!
• No power supply yet; I use my desktop lab supply for now
• The caps are Samwha RD; perhaps not in the spirit of the thread, but I just had them
• The output transistors are D44H11 and D45H11 (I could not match MJFs, so I used what I could match; had to add some insulation though)
• Resistors are RN55/RN60 and Panasonic ERX3
• No case yet, plan to use one from modushop/HIFI2000

 

Question: I want to use a high resistance volume control pot (50k or 100k). Would it be ok to increase the resistance between the gate of the input JFET and the ground so as not to load the pot too much? What would be a practical limit on this? 1Meg?

 

Thank you!

You can probably change R36 to 100k. If you go any higher you might have to change C1 a bit.

You can probably leave everything alone and use a 50k pot.

Thank you Kevin!

Went ahead and populated the psu BOM at Mouser - http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=e580be76a8 , can you guys see it? I think I may have gotten some counts/values wrong, I definitely added extra for a few caps at the very least, etc.

 

What would you need to change the diodes and resistors to to get a different rail supply, such as +/- 35 like what Kevin mentioned?

Edited September 2, 201313 yr by nopants

I can't see anything missing from the BOM. The counts seem fine, except for the caps as you pointed out.

here is the bom for the dual zener regulated power supply

less the heatsink which i'm too lazy and tired to look up at the moment.

the hole sizes for the zeners are going to be a bit tight.

will be fixed on the next rev of the board

 

 

old power supply

    1000uf/35v         871-B41041A7108M000             8

4700uf 50v ls10mm 35 dia            598-SLP472M050C5P3            2

1n4750       512-1N4750ATR     2   

1n4748      512-1N4748ATR      2

mfj15030            863-mjf15030g      4

mjf15031            863-mjf15031g     4     

bridge rectifier    625-G3SBA20-E3/51 2

750 ohm           71-rn60d-f-750         2       

562 ohm 71-rn60d-f-562           2

3 pin terminal           651-1729131          2

2 pin terminal            651-1729128          2

Edited September 16, 201313 yr by kevin gilmore

Thanks, Kevin.

 

I think we also need 4 x 0.1uf film capacitors (80-R82EC3100DQ70J)

Edited September 16, 201313 yr by fordgtlover

yep.

fix later.

Most excellent as I just got way too many of these boards.   

moar better now

old power supply
1000uf/35v 871-B41041A7108M000 8
4700uf 50v ls10mm 35 dia 598-SLP472M050C5P3 2
1n4750 512-1N4750ATR 2
1n4748 512-1N4748ATR 2
mfj15030 863-mjf15030g 4
mjf15031 863-mjf15031g 4
bridge rectifier 625-G3SBA20-E3/51 2
750 ohm 71-rn60d-f-750 2
562 ohm 71-rn60d-f-562 2
3 pin terminal 651-1729131 2
2 pin terminal 651-1729128 2
.1uf ls 5mm 80-R82EC3100DQ70J 4
heatsink 532-529902b25g 4

thermal washers  8

new power supply
220uf 50v ls 5mm dia 10mm 647-UPW1H221MPD 4
bridge rectifier 625-G3SBA20-E3/51 2
10 ohm 71-rn60d-f-10 1
100 ohm 71-rn60d-f-100 2
511 ohm 71-rn60d-f-511 2
750 ohm 71-rn60d-f-750 2
1k ohm 71-rn60d-f-1.0k 2
2k 71-rn60d-f-2.0k 4
10k 71-rn60d-f-10k 2
op27 use something else 2
4.7uf 505-MKS24.7/63/5 2
3 pin terminal 651-1729131 1
2 pin terminal 651-1729128 2
mfj15030 863-mjf15030g 1
mjf15031 863-mjf15031g 1
zener 13v .5w 78-BZX55B13-TAP 2
lm4040-2.5 926-LM4040DIZ25NOPB 2
.1uf ls .1 too lazy to look up 2
mj15024 863-MJ15024G 1
mj15025 863-MJ15025G 1
pnp mpsw56 1
npn mpsw06 1
heatsink 532-568303B00 2

thermal washer   739-A15038003  2

Edited September 17, 201312 yr by kevin gilmore

Hi

 

I am in the UK and have the option of the LSK389 in a,b,c and d options from a UK source? The data sheets look identical and the prices are all similar - what version do you think is the best?

 

Cheers

 

John

Hi

I am in the UK and have the option of the LSK389 in a,b,c and d options from a UK source? The data sheets look identical and the prices are all similar - what version do you think is the best?

Cheers

John

There was an article in AudioXpress a while back that noted the A to be lowest noise if you do not need the higher Idss.

I can't believe trendsetter charges 20$ for shipping, I ordered direct from linear when I got my kgsshv parts- I believe they're about 6 a piece that way. I'm also local so that cut down on shipping. Have to order over the phone but that's a small barrier.

there is a grounding error on the zener power supply on the final output cap

on the minus power supply. the wrong side of this cap is grounded causing

the minus supply to be grounded. simple fix, use a drill bit on the top to

un-ground the grounded hole, then add a jumper on the bottom to the other

side of the cap to the other cap to ground.

 

http://gilmore.chem.northwestern.edu/dsc_0469.jpg

http://gilmore.chem.northwestern.edu/dsc_0470.jpg

Edited September 21, 201312 yr by kevin gilmore

both supplies now fully tested and i'm really happy with each of them.

the bigger one easily does 1 amp, so enough to run a pair of boards for balanced.

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