HRD Portable Amp (sans DAC)
Dec 27, 2008 at 12:26 AM Thread Starter Post #1 of 8

feifan

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Hi. I just purchased a used HRD Portable Amp (sans DAC). The handwriting on the label, on the bottom, isn't completely legible. I think it says "2/1/07" and "211206." It came with a brick PS (model APS48-ER-125) that connects via a 5-pin DIN on the back. It also has a 5VDC "battery" jack to recharge the internal battery. The package didn't include an adaptor for this jack.

I've been running the amp via an Astrodyne PS for over 3 hours and find that the battery isn't recharging. I have the "battery power" switch in the "off" position while the DIN PS is engaged.

Question 1: Is the battery dead?

Question 2: Will I need to get the 5VDC recharger to charge the batteries or should the batteries be recharging via the DIN PS?

Question 3: Am I losing any SQ by running the amp via DIN? Or put another way, does the dead battery affect the SQ?

Question 4: The amp didn't come with a manual, and I couldn't find one on the HeadRoom site. Is one available? (I did find the manual for the amp + DAC combo.)

I've always wanted an HRD amp only unit and I was happy to find this.

Thanks in advance for any info you can provide on this "rare" amp.
 
Dec 27, 2008 at 9:42 AM Post #2 of 8

TheSloth

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Quote:

Originally Posted by feifan /img/forum/go_quote.gif
Hi. I just purchased a used HRD Portable Amp (sans DAC). The handwriting on the label, on the bottom, isn't completely legible. I think it says "2/1/07" and "211206." It came with a brick PS (model APS48-ER-125) that connects via a 5-pin DIN on the back. It also has a 5VDC "battery" jack to recharge the internal battery. The package didn't include an adaptor for this jack.

I've been running the amp via an Astrodyne PS for over 3 hours and find that the battery isn't recharging. I have the "battery power" switch in the "off" position while the DIN PS is engaged.

Question 1: Is the battery dead?

Question 2: Will I need to get the 5VDC recharger to charge the batteries or should the batteries be recharging via the DIN PS?

Question 3: Am I losing any SQ by running the amp via DIN? Or put another way, does the dead battery affect the SQ?

Question 4: The amp didn't come with a manual, and I couldn't find one on the HeadRoom site. Is one available? (I did find the manual for the amp + DAC combo.)

I've always wanted an HRD amp only unit and I was happy to find this.

Thanks in advance for any info you can provide on this "rare" amp.



Well, firstly it's not rare. It's much more common than the current generation. It's simply the last model DP which was around from '05 - '07.

Secondly, and sorry to disappoint you, the battery doesn't charge because there isn't one. The 5V socket is for the external battery pack which took 4 D cell batteries. Best SQ was with full power through the DIN socket as you are using.
 
Dec 27, 2008 at 1:09 PM Post #3 of 8

feifan

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Quote:

Originally Posted by TheSloth /img/forum/go_quote.gif
Well, firstly it's not rare. It's much more common than the current generation. It's simply the last model DP which was around from '05 - '07.

Secondly, and sorry to disappoint you, the battery doesn't charge because there isn't one. The 5V socket is for the external battery pack which took 4 D cell batteries. Best SQ was with full power through the DIN socket as you are using.



thanks, thesloth. not disappointed at all on both counts. i'm glad it's not rare. it means others may be able to help if i have any questions. also i'm planning to run it on ac so i'm glad this offers the best sq. thanks.

another question: are the amp specs the same as the amp+dac version?

still another: i feel a grating when the volume knob reaches 10 o'clock and beyond. other than the odd sensation, it doesn't seem to affect sq. is this something i need to worry about? is there a quick fix?

thanks, again.
 
Dec 27, 2008 at 2:46 PM Post #4 of 8

mrarroyo

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Quote:

... i feel a grating when the volume knob reaches 10 o'clock and beyond ...


Grating on volume pots is quite common IMO. Sometimes just by using it (rotating the volume pot) the grating goes away. Another option is to go to Radio Shack and purchase the tuner cleaner/lubricant spray. Then you carefully open the unit and spray via the openings you will see on the volume pot, I slant the unit so any fluid (which dries quickly but leaves a lubricant) runs out of the unit unto a paper towel or cup to collect it. After spraying rotate the knob and repeat. The grating should not be there.

Congratulations on your new amp, it is a very nice unit.
 
Dec 27, 2008 at 3:38 PM Post #5 of 8

feifan

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Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif
Grating on volume pots is quite common IMO. Sometimes just by using it (rotating the volume pot) the grating goes away. Another option is to go to Radio Shack and purchase the tuner cleaner/lubricant spray. Then you carefully open the unit and spray via the openings you will see on the volume pot, I slant the unit so any fluid (which dries quickly but leaves a lubricant) runs out of the unit unto a paper towel or cup to collect it. After spraying rotate the knob and repeat. The grating should not be there.

Congratulations on your new amp, it is a very nice unit.



Thanks, mrarroya. The grating seems to be limited to the 10-2 o'clock range. I tried rotating the volume pot back and forth over the grating area to clear it up but the problem persists. I'll try the lubrication step when the problem becomes a problem. Right now, with the gain at medium, the volume doesn't clock past 08:45

I'm testing it now with computer as source > optical out via the X-Fi console > TC-7510 (DAC) > HRDPA > HD650. My initial impression is that the SQ is very good in this lineup, about an 8 out of 10. The sound is slightly veiled, and fatiguing after about ten minutes. However, these results may be due to the other components or my condition at the moment -- in need of sleep.
 
Dec 31, 2008 at 3:54 PM Post #6 of 8

Tyll Hertsens

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Could it be the knob being too close to the front panel, and something is rubbing?

These are the things you should call in or email support@headphone.com if they're of concern. We do it way better that way than here on the forums.

Though I have to express a big thanks to the thesloth, mrorroyo, and all the guys for hanging our handling all the technical help here, they're damn near as good as we are in many ways... better in that they're faster with info often.
 
Jan 1, 2009 at 8:16 AM Post #7 of 8

feifan

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Quote:

Originally Posted by Tyll Hertsens /img/forum/go_quote.gif
Could it be the knob being too close to the front panel, and something is rubbing?


Bingo! Thanks, Tyll. Loosened the knob with the smallest hex driver I have, 1.5mm, pulled it out a bit, tightened it, and the scraping's gone. Now why didn't I think of that?

While I was at it, I decided to see how the rubber bumper's attached to the case. I loosened the 2 face screws with the same hex driver; removed the nuts around the 1/4" headphone jack with a 7/16" socket. Cool. It serves as a gasket and a bumper. The fit is snug, but it's easily removed and reset. Nice work.

The HRD-SE maxed and the HRDB with Home module/DAC are my main listens, but I've never opened them up. Haven't had to. Worked beautifully from the get go.

I'm planning to use the HRDPA as an away amp -- "away" as in away from the desk, even if it's just across the room.

Thanks again, everyone.
 
Jan 1, 2009 at 4:02 PM Post #8 of 8

mrarroyo

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Quote:

Originally Posted by Tyll Hertsens /img/forum/go_quote.gif
Could it be the knob being too close to the front panel, and something is rubbing? ...


Damn, I feel like a fool!
redface.gif
I just had to do the same w/ an amp from a different maker, should have thought of it and posted it. Sorry.
 

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