[DaKi][er]

Quote:

Originally Posted by robzy Well..... there goes that idea. Methinks ill just splurge on some nice caps then. [edit]: Shoulda said thanks for doing the measurements. Thanks muchly, 'tis apreciated [edit2]: I do realise that while this is an awesome DAC it might not warrant fancy-ish caps, but i cant resist. Rob.

that is <20mV and you think that is too high? your dynalo will take that just fine

 

[robzy]

The gain of the Dynalo is around 6/7. That would mean just under 130mV of offset for the servo to deal with. From my experience of mucking around with the dynalo it can take it a while too bring this down to a usable level.

Am i mistaken though? (At the time i tested it by dynalo had major problems which could have contributed to problems with the servo, so its a possibility)

Rob.

 

[DaKi][er]

Quote:

Originally Posted by robzy The gain of the Dynalo is around 6/7. That would mean just under 130mV of offset for the servo to deal with. From my experience of mucking around with the dynalo it can take it a while too bring this down to a usable level. Am i mistaken though? (At the time i tested it by dynalo had major problems which could have contributed to problems with the servo, so its a possibility) Rob.

do you listen at full volume all the time? the pot on the input is going to attenuate that otherwise

as well as 130mV while not a good value, wont be damaging to headphones

 

[tomb]

From the looks of things, the Group Buy deliveries may be received soon. Sorry for being such a lazy you-know-what: but if anyone comes up with a spreadsheet that has specific Mouser/DigiKey catalog numbers for Alf's part list - please post it.

 

[MisterX]

A BOM is posted here----->

http://www6.head-fi.org/forums/showp...&postcount=483


You may want to double check the # given for R15 & R16 though

 

[Alf]

Just a thought. Maybe we should start a separate construction thread. This one is already 31 pages long. With over 50 people joining the group buy, this thread would become unreadable in a matter of days.

 

[panterka]

My DAC << link

Capacitors in analog part Panasonic FC 1000uF for +-15V and for 3,3V I put in Rubycon ZL 2200uF. Uncoupling this Panasonic FC 100uF - in future I would want to check Rubycon BG STD 100uF/16V. For lini 3,3V and 5V work Sanyo OSCON 220uF. Coupling mass Aanalog and Digital - Rubycon ZL 180uF. Diode in bridge of analog part - BYV27-200. Solid capacitors in most WIMA.
Capacitors out WIMA MKP10 4,7uF.
Exchanged stabilisers became also on low pompous: 5V - LM2940T and 3,3V LM2937ET.

From amplifiers I tested OPA2604, AD797, AD8066. OPA627BP, became favourite at present AD797.

 

[robzy]

Quote:

Originally Posted by DaKi][er do you listen at full volume all the time? the pot on the input is going to attenuate that otherwise as well as 130mV while not a good value, wont be damaging to headphones

*slaps forhead* I forgot about the pot.

I guess what the best thing to do would be to wait, build it, hook it up with a dummy load, and try it out and see if im comfortable with how its operating.

Thanks for the help,
Rob.

 

[.: ZMN :.]

@ MisterX

That Digikey BoM was for Alien DAC v1.0R5. Please check if it suitable for v1.1, there were some changes in the recommendations on Alf's website since I ordered parts, IIRC, but it could still be helpfull anyway.

 

[.: ZMN :.]

Just finished a v1.0R5 Alien DAC.

Few comments:
- Alf, thank you!
- And all others that contributed, thank you!
- I had never done anything smaller than through-hole resistors. The links to tutorials were very helpfull (I settled for DaKiller's method combined with what I saw in tangent's videos)
- The description on R32/R31/C32 was a little confusing. In an 'adjustable' setup the C32 goes below, the R32 on top and the R31 must also go below, right??
- I can only add to the advise to use magnifying glasses and a lot of light.
- It's hard to leave it alone while burning in, it sounds very good allready!

I shall post some pictures of my Pimeta-Alien DAC combination soon. Hopefully it will pursuade others and get a second GB for the boards on it's way!

(yeah, I missed the first one

).

A last thing on parts costs:
My options were limited to a single order from Digikey, which resulted in a considerable addition to the costs (P&P by Express, high clearance costs; total to approx. $60 for my location). A GB for the ICs would be benificial.

 

[threepointone]

just wondering, how exactly do you choose a low-jitter oscillator?

 

[t52]

hi all!

first of all thanks to everyone who contributed to this nice little circuit and pcb. my question is about the ferrite beads in the supply lines of the pcm2702 - how does one choose these thingies? based on inductivity, when yes - what's a good starting point (i remember reading that 10uH was a good value to start with). when checking farnell i only could find smd beads where the impedance at working frequency was given in Ohms, are these suitable as well, if so - which impedances?

thanks in advance and best regards, juergen

 

[Alf]

Quote:

Originally Posted by threepointone just wondering, how exactly do you choose a low-jitter oscillator?

Go for the one with the best accuracy. It also happens to be the most expensive one.

 

[Alf]

Quote:

Originally Posted by t52 hi all! first of all thanks to everyone who contributed to this nice little circuit and pcb. my question is about the ferrite beads in the supply lines of the pcm2702 - how does one choose these thingies? based on inductivity, when yes - what's a good starting point (i remember reading that 10uH was a good value to start with). when checking farnell i only could find smd beads where the impedance at working frequency was given in Ohms, are these suitable as well, if so - which impedances? thanks in advance and best regards, juergen

Farnell stocks Murata BLM31AJ601SN1L specified in the part list. It is perfect for the application.

 

[threepointone]

Quote:

Originally Posted by Alf Go for the one with the best accuracy. It also happens to be the most expensive one.

so do i go for the one with the lowest ppm rating or most zeroes, or what?