A New Take on the Classic Pass Labs D1 with an ESS Dac

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Glad to hear you're still up for sourcing/matching the FET's qusp! Couldn't resist :)

:cuss:

Hi Guys,

Alright, so we've got two volunteers out of a possible three:

USA - MisterRogers - Has previously done a GB and knows how to poke fun at qusp! That's two pluses in my books.

Asia / Australia - qusp - No worries here either, so that's confirmed.

Europe - ?

As for the mosfets, I'll mull it over, as I might be able to dedicated some time to this. I already have the set up to do it, so I'll see if I can dedicated a few extra days to matching fets. They won't be cheap, however, since it's at least an hour per set in overall time plus the cost of the parts. My count is 37 quads of fets which means I would need to order a rail of 250 pcs to get enough good matches.

Cheers,
Owen

haha yep thats a plus in my book too

no worries on the rest, yeah I thought about it, i've still got the rig from last time and it worked out pretty well in the end after doing the research and building it, but I just cant justify taking that time, it would take me longer than your estimate since i'm sure you can attach a number of probes at once and maybe get it done quickly enough that tempco drift isnt as much an issue. if I used Zfoils for all the resistors in the test rig it would only leave the fet itself affected. if I were doing it again I would look at heating the heatsink actively so it could be kept at the same temp whatever time of day it was instead of waiting for it to heat up to a certain temp and stopping when it drifted too much.

that being said my rig was testing to a silly amount of zeros and drift probably wasnt as much an issue as it appeared.

Hi Qusp

Please count me for two sets of keratherm red isolation pad.

Thanks

will do

Don't go double selling that keratherm mate, I still need my bits out of that sheet! :p


I don't have time to organise matching of any more FETs at this stage either.

hahas yeah sure, no worries I have enough

+1 on the keratherm reds - let me know cost. I should be in for at least 4 if not more. thanks

done

Hi,

What is the keratherm reds ?
(thermal interface material) its not a tweak for audio quality, just longevity, much better heat transfer to the heatsink than silpads


keratherm Red TIM orders

bigpandahk
kasey


hey we could do Zfoil resistors again if people are keen, easiest would be to send out to the regional distributors, i'd have to order pretty son though, as theyre made to order
 
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yeah I can handle that, as I dont think that will be too large and I was planning to make an order with them soon anyway. now that i've actually used the board for a while and have a better idea of what they are expected to dissipate, we can use them for both power resistor positions (2 x 200R and 2 x 400R per channel) i'm using 2 x tx220Z @400R and 2 x TX220S @220R. I initially thought the 12W rating might not be enough for the 200R position, but its fine.
 
yeah I can handle that, as I dont think that will be too large and I was planning to make an order with them soon anyway. now that i've actually used the board for a while and have a better idea of what they are expected to dissipate, we can use them for both power resistor positions (2 x 200R and 2 x 400R per channel) i'm using 2 x tx220Z @400R and 2 x TX220S @220R. I initially thought the 12W rating might not be enough for the 200R position, but its fine.

Let me be the first to join the GB.
 

opc

Member
Joined 2004
Paid Member
Hi Guys,

Good news and bad news...

Good news first:

The design passed DFM no problem and should be in production now. It's also slated for a three day turn as there was no cost savings going for a longer lead time since it's only a 2 layer board. I should have the boards by the end of this week or early next week.

Bad news:

Because of the size of the board, the maximum order size was a quantity of 56 pieces before being forced into a custom spec order. That would add tooling costs to the order and push the total board cost up dramatically (more like $35 each vs. $25 each) For that reason, I opted for the lower quantity which means some of the later orders might not get filled.

I'm actually expecting a higher than normal dropout rate for this project overall since it has been so long, so I would imagine there will be enough boards to keep everyone happy.

This is just a heads up to let everyone know.

I'll keep you all posted with the status, and I'll send out pictures of the boards when they arrive, and payment requests after that.

Cheers,
Owen
 

opc

Member
Joined 2004
Paid Member
Yeah... it didn't make much sense to me either, and I had to call them to get them to explain it. It has to do with how much surface area they can do in a batch, and if you exceed that, you have to make your order a custom spec which has a tooling fee, and takes 4 weeks to get the same pricing as the 3 day turn on the standard spec order.

I've never run into this problem before because I've never ordered so many large boards.

Either way, it is what it is, and I don't think it will be that big a deal in the end. There should be enough to go around, and this way we get the boards a little faster.

Cheers,
Owen
 
:cuss:



haha yep thats a plus in my book too

no worries on the rest, yeah I thought about it, i've still got the rig from last time and it worked out pretty well in the end after doing the research and building it, but I just cant justify taking that time, it would take me longer than your estimate since i'm sure you can attach a number of probes at once and maybe get it done quickly enough that tempco drift isnt as much an issue. if I used Zfoils for all the resistors in the test rig it would only leave the fet itself affected. if I were doing it again I would look at heating the heatsink actively so it could be kept at the same temp whatever time of day it was instead of waiting for it to heat up to a certain temp and stopping when it drifted too much.

that being said my rig was testing to a silly amount of zeros and drift probably wasnt as much an issue as it appeared.



will do



hahas yeah sure, no worries I have enough



done


(thermal interface material) its not a tweak for audio quality, just longevity, much better heat transfer to the heatsink than silpads


keratherm Red TIM orders

bigpandahk
kasey


hey we could do Zfoil resistors again if people are keen, easiest would be to send out to the regional distributors, i'd have to order pretty son though, as theyre made to order
Hi qusp!
Glad to get keratherm pads suited for this Pass project.
Could I opt for the needed Zfoils as well?
If you know a way to get the needed fets matched, please give me a hint and do I understand there is a thought about a parts GB?
Cheers,
Ed
 
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Would these heatsinks be sufficient for NTD1?


http://www.diyaudio.com/forums/swap-meet/220314-fs-aluminium-heat-sinks.html#post3177377

Alu @ 250mm x 100mm x 40mm, and weigh approx. 1.2kg each.

No meaningful thermal resistance specified but manufacturer's page here - European Extrusion Profiles

If these are in suitable and people are interested we could potentially organise to get a few off him and sent to us in Brisbane and we'll distribute from here combined with whatever else we're posting out (pcbs, keratherm, zfoils etc).


EDIT:

I just had a search for the conrad heatsinks used by some in the previous run of these boards, they were a bit smaller than this I think? Roughly they were 120x150mm

The big if is on dissipation figures but if they are ok this might give some extra space for other shunt regs on the same heatsink potentially
 
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how bizarre, it costs more to get more? can you not make a second small order? =) joking, but thats odd.

Qusp,

I've got pricing for TZ220Z 400R00 0.1% and TZ220S 200R00 0.1% with price break.

Did you get pricing on your side?

Just want to make sure we get the best pricing possible.

Do you need any help? We could do the same as for the boards. Get one person in Australia, Europe and USA to ship them out.

Thanks
Do
 
it doesnt make any sense to create another network for resistors when there is other stuff already going out. they will either go out to the regional PCB distributors along with keratherm, or direct. postage for a few resistors isnt a big deal and I doubt the GB for them will end up very large due to price. so it might be more trouble than its worth doing the regional thing. i'm not sure if the price list I have is OEM as i've only had dealings with them with my business, so i'de rather not post publicly, i've sent you a PM
 
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