Chillzone21
100+ Head-Fier
- Joined
- Nov 16, 2015
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Does it use burr brown?
I have 2 HPA-1s. Bought a mint/used 2012 v.2 model for a gift desktop system I'm setting up for my brother, and when I heard how good it sounded (shockingly musical in my system), I promptly purchased another used one, an extremely mint 2013 v.2 model for myself.
I changed the volume knobs on both--the originals are impossible to see and don't feel very good to actually handle/adjust--and ordered the OPA627AP opamp (on browndog adapter) which I'll put in my 2013 HPA-1. It already sounds very nice...just hoping to fine-tune that niceness.
Someone mentioned possibly driving the Fostex TH-X00s with the M Stage HPA-1 a few msgs back in this thread. I have done that w/my TH-X00, and the HPA-1 drives it about as well as any other HP amp on hand (the TH-X00 aren't a difficult load in my experience).
Something I should emphasize about the HPA-1 that no one else seems to remark on: it works exceedingly well as a preamp. True, there are only 2 inputs (2 RCA input pairs), which is fewer than the 4-6 inputs found on most full-function preamps. But on the desktop, that's really more than enough. I use the RCA inputs from my DAC, and send the output of the HPA-1 to my powered speakers (Swan M200 MkIII) + sub. The volume control of the HPA-1 works silently & well...no pops or surprises (important w/powered speakers!).
In the coming weeks I'll replace my current DAC (Peachtree Audio DAC ITx) with an Audio GD NOS 19, and I'll run it through the HPA-1. That's a huge DAC upgrade, and it tells you how well I regard the HPA-1 as a preamp...
I have 2 HPA-1s. Bought a mint/used 2012 v.2 model for a gift desktop system I'm setting up for my brother, and when I heard how good it sounded (shockingly musical in my system), I promptly purchased another used one, an extremely mint 2013 v.2 model for myself.
I changed the volume knobs on both--the originals are impossible to see and don't feel very good to actually handle/adjust--and ordered the OPA627AP opamp (on browndog adapter) which I'll put in my 2013 HPA-1. It already sounds very nice...just hoping to fine-tune that niceness.
Someone mentioned possibly driving the Fostex TH-X00s with the M Stage HPA-1 a few msgs back in this thread. I have done that w/my TH-X00, and the HPA-1 drives it about as well as any other HP amp on hand (the TH-X00 aren't a difficult load in my experience).
Something I should emphasize about the HPA-1 that no one else seems to remark on: it works exceedingly well as a preamp. True, there are only 2 inputs (2 RCA input pairs), which is fewer than the 4-6 inputs found on most full-function preamps. But on the desktop, that's really more than enough. I use the RCA inputs from my DAC, and send the output of the HPA-1 to my powered speakers (Swan M200 MkIII) + sub. The volume control of the HPA-1 works silently & well...no pops or surprises (important w/powered speakers!).
In the coming weeks I'll replace my current DAC (Peachtree Audio DAC ITx) with an Audio GD NOS 19, and I'll run it through the HPA-1. That's a huge DAC upgrade, and it tells you how well I regard the HPA-1 as a preamp...
First off, you need a 1.5mm hex wrench (the 90 degree kind) to remove the stock volume knob. That's not a common size--smaller than usual. I had to go to Harbor Freight and buy a big set, of which the 1.5mm is the smallest wrench.
Then I spent a crazy # of hours online looking for a volume knob that would fit the width (30mm) and rather long depth of this volume pot's shaft. I ended up buying 2 pairs from GD Parts on ebay (I have 2 x HPA-1's)--but oddly, only 1 pair actually fit.
Here's the listing for the pair that fits (and actually good & in proportion to the HPA-1):
http://www.ebay.com/itm/Full-Aluminum-Pointer-Knobs-for-Amplifier-CD-DAC-Radio-Turntable-30x22mm-Black-2-/321976848465
If you want a single volume knob like this, you'll just have to slog through the listings from GD Parts store on ebay.
Oddly, the replacement knob requires a 2mm hex wrench, not the 1.5mm wrench used to take off the stock knob (go figure).
FYI, it takes a full 2 weeks for the order to arrive via ePacket from China.
It's still a bit difficult hard to see what volume the replacement knob is set to in very low lighting--but in any semi-normal lighting you can see this knob just fine, unlike the stock pot, which is just about impossible to see in any lighting. It also feels a lot better "in the hand" when you're using it...
With the sole caveat being that the stock volume knob of the HPA-1 (as explained above) is a pain to see & use, this amp otherwise is an extremely functional & rational pre-amp solution for powered speakers. In 4+ months of using mine as a preamp, I've never has a single odd noise, burst of static, or other unexpected event.
BTW, when you plug headphones into the HPA-1, it mutes the line-out to your speakers. Some people like that; others don't. But it works exactly as designed, and again, I've never had a moment of noisy/unexpected behavior from the unit when plugging/unplugging 'phones.