[tomb]

  Hey Everyone,
 
I just finished building my Doodlebug, and am currently enjoying a well-deserved listen to my "reference album" (and a beer ). The build itself I found to be quite easy, especially using the build-by-photo instructions on the diyfroums.org-site. I used a 25W soldering-iron, which, for some parts was not quite sufficient for parts connecting to the ground-plane, due to heat-drainage. At some point, I will give the whole thing a once-over with a bit more heat. 
 
I have a question that may have already be answered, but I couldn't find the answer to, namely: to what voltage should I set the Doodlebug when I have it connected to the pupDAC? For now, I've set it to 5.25V (using a 9VAC 500mA wallwart). 
 
I hope anyone can help out!
 
KR,
 
Gijs

 
You're perfect!

  5.25VDC is exactly what's needed to ensure that all the numerous regulators on the PupDAC have sufficient "headroom" to maintain regulation.
 
Many thanks for the kind comments and congrats on your listening!  The PupDAC with the DoodleBug (set to 5.25VDC) is my primary source.  It sounds glorious with the Torpedo III.  I may be shilling, but that's my end game so far.  I am now trying my best to figure out how to finance a pair of HD800's. 

 

 

[Gijs]

Thanks Tom! I hadn't checked these forums for a while and completely missed the arrival of the Torpedo III. You're not the only one with financial dilemma's now... For now, I will have to make do with the Torpedo I with a pair of Philips tubes. Oh well... But, joking aside, the Doodlebug is a massive upgrade to my little system! Keep up the good work!

 

[hembergler]

Another happy builder here--finished up a Doodlebug and pupDAC from Tom's immaculate kits and added them to my work setup. Sounds wonderful... a bit too good for being at work

 
The ground plane on the Doodlebug was a little bit more challenging than I expected, I don't think I've ever had to turn my iron up as high as I did for that. All in all a lot of fun to build and great to listen to. Thanks tomb/Avro!

 

[39points]

Looks interesting

 

[tomb]

  Another happy builder here--finished up a Doodlebug and pupDAC from Tom's immaculate kits and added them to my work setup. Sounds wonderful... a bit too good for being at work

 
The ground plane on the Doodlebug was a little bit more challenging than I expected, I don't think I've ever had to turn my iron up as high as I did for that. All in all a lot of fun to build and great to listen to. Thanks tomb/Avro!

Yep - those are massive ground planes on the DoodleBug, but it contributes to the low noise of the power supply.
 
Thank you for the wonderful comments!

 

[nikobi]

Hi,
 
Trying to test my doodlebug, as I suspect something is wrong.
Unfortunately I have only one computer with USB 3 connectors only and an unsoldered as-of-yet pup-dac kit.
 
My doodlebug looks OK, both LEDs light up (12V dc power dupply), voltage between test points is 5.25v but I cannot make it work.
Is it ok to use a USB mouse or keyboard to test the doodlebug?
When I connect a spare usb mouse, the mouse led does not light up and no connection is made.
I tried to use it with my only other usb component, a musical fidelity V-dac II, but that did not work either, but that might be a high-speed device.
Any input is welcome,
 
Nik

 

[Avro_Arrow]

The Doodlebug does nothing on it's own, that is, it is not recognized as
a device by the computer. It is locked at USB full speed and will not
work with devices at USB low speed or USB high speed.
If you have a mouse that runs at USB full speed, it should work, but
I think most mice are USB low speed devices.
The 5.25 volts shows the power supply is working properly.
New devices (ones that have not been connected to your computer
before), may need to be plugged in on their own and be recognized
by the computer before being used through the Doodlebug.
 
In short, there is nothing to indicate you have a problem.
Get your pupDAC up and running then you can test the Doodlebug.
 
Cheers!

 

[nikobi]

OK, thanks for the heads-up Avro_Arrow - I'll finish my pupDAC and report back. This is probably going to take a week or two, though.
Cheers,
Nik

 

[nikobi]

OK, so I've finished my pupDac now. Unfortunately something does not seem to work.
When I connect the pupDac to my Ipad (via connection kit), Ipad shows a message along the lines of: "Device not available. Connected device is using too much current".
Then, when I connect the Doodlebug nothing happens.
Doodlebugs two LEDs light up, pupDacs LED does not. Dac is not recognized (no error message, Ipad plays music through internal speaker).
 
Now, unfortunately, my Ipad is my only non-USB3 device. Makes it hard to try things.
 
What I noticed:
I do not trust the small mini-usb jack (computer side). The plug does not go in very far and it does not give a locking sensation like the one from the pupdac does.
The Voltage regulator gets really warm, but then that might be just a part of its job?
Any ideas what I can try?
Cheers,
 
Nik

 

[ericj]

Just noticed this thread. 
 
I would like to have a USB isolator but not for audio purposes. 
 
Does this provide full galvanic isolation of the USB device? By that i mean, does it break all DC paths between the host computer and the USB device? 
 
A year or so back i let the magic smoke out of a $350 diagnostic interface (Rosstech HEX+CAN) and had to pay $150 for out of warranty repair -- because i had the laptop powered by the car when i connected the interface to the OBDII port. 
 
Somehow even though the ground at the laptop's dc power supply was at the same potential as the car's ground, ground at the usb port was far enough different that i cooked the diagnostic interface. 

 

[Avro_Arrow]

  Just noticed this thread.


 
I would like to have a USB isolator but not for audio purposes.


 
Does this provide full galvanic isolation of the USB device? By that i mean, does it break all DC paths between the host computer and the USB device?


 
A year or so back i let the magic smoke out of a $350 diagnostic interface (Rosstech HEX+CAN) and had to pay $150 for out of warranty repair -- because i had the laptop powered by the car when i connected the interface to the OBDII port.


 
Somehow even though the ground at the laptop's dc power supply was at the same potential as the car's ground, ground at the usb port was far enough different that i cooked the diagnostic interface.

Yes, it provides complete galvanic isolation. Just make sure your device works at USB full speed, not low speed or high speed.
 
Edit: I think your interface may be a low speed device. Contact the manufacturer to make sure.
The Doodlebug can be hacked to run at USB low speed.

 

[Avro_Arrow]

  OK, so I've finished my pupDac now. Unfortunately something does not seem to work.
When I connect the pupDac to my Ipad (via connection kit), Ipad shows a message along the lines of: "Device not available. Connected device is using too much current".
Then, when I connect the Doodlebug nothing happens.
Doodlebugs two LEDs light up, pupDacs LED does not. Dac is not recognized (no error message, Ipad plays music through internal speaker).


 
Now, unfortunately, my Ipad is my only non-USB3 device. Makes it hard to try things.


 
What I noticed:
I do not trust the small mini-usb jack (computer side). The plug does not go in very far and it does not give a locking sensation like the one from the pupdac does.
The Voltage regulator gets really warm, but then that might be just a part of its job?
Any ideas what I can try?
Cheers,


 
Nik

USB 3 ports are backward compatible with USB 2
Sounds like you have a short in your pupDAC
The voltage regulator usually gets only mildly warm, not much above room temperature
in normal use. The Doodlebug can protect itself from shorts with an auto reset fuse.
Go over all the solder joints and look for any bridges.

 

[ericj]

 
Yes, it provides complete galvanic isolation. Just make sure your device works at USB full speed, not low speed or high speed.
 
Edit: I think your interface may be a low speed device. Contact the manufacturer to make sure.
The Doodlebug can be hacked to run at USB low speed.

 
Pretty sure i can just ask the usb stack.
 
Good to know. I may build one of these. 
 
Can't tell you how annoyed i was to discover that a $350 diagnostic cable isn't isolated. 

 

[mcandmar]

A year or so back i let the magic smoke out of a $350 diagnostic interface (Rosstech HEX+CAN) and had to pay $150 for out of warranty repair -- because i had the laptop powered by the car when i connected the interface to the OBDII port. 

 
Don't like the sound of that, how were you powering your laptop?   I use mine with a cheap DC-AC inverter powering the stock laptop power supply and never had a problem, but you have me worried now...

 

[ericj]

   
Don't like the sound of that, how were you powering your laptop?   I use mine with a cheap DC-AC inverter powering the stock laptop power supply and never had a problem, but you have me worried now...

 
A cheap inverter might be the safer way to do it, depending on the inverter. A lot of them do use a transformer.
 
I was using a Power+ brand DC-DC power supply that was made specifically for the laptop. 
 
Ross-tech says to check for current between the ground on the usb shell and the ground of the car. They also think this only happens with "cheap, generic, universal" adapters.