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Pocket Amp by Electric Avenues - Page 3

post #31 of 92
I use mine everyday.

Great little amp and very light on battery use!!!

Thumbs up to Gary!!!
post #32 of 92
Quote:
You'll be surprised how low an in put you need if you use it this way although Gary says it is best to adjust mp3 to 50-60% and use the volume control on the PA2, even to attenuate the signal.
Yep, I found that I only needed to raise my mp3 player's volume to about 20% to get the best sound with my PocketAmp.
post #33 of 92
Quote:
Originally Posted by gshan
Yep, I found that I only needed to raise my mp3 player's volume to about 20% to get the best sound with my PocketAmp.
Same for me with Grado 80's. Although I'm not (yet) aware of the difference it makes - I'd like to know what the effects of using it as an ATTENUATOR rather than an amp.

If you do as Gary says - you have your mp3 at 50% or so. Then you adjust the volume with the Pocket Amp. This means that the output direct from my mp3 is louder than what I'm listening to through the amp.

Makes me wonder -

Where does the wasted power go?
What effect on sound?
Is this actually a good way to use the amp?

Now I'm confused!!!
post #34 of 92
I also have a recently ordered PA2, and for the price I don't think there is anything better. It works as advertised and Gary is easy to deal with. I wish the two input and output jacks were labelled, but Gary does have instructions on his web page. He also ships promptly and is just plain easy to deal with. The PA2 doesn't sound as good as my MisterX Portable Pimeta, but the battery life is better and the PA2 is half the size (and about half the price too).
post #35 of 92
I can't use my PA2 to attenuate; anything less than 6'o clock, and the left side is louder than the right & the right side is staticy.
post #36 of 92
Quote:
Originally Posted by sumone
I can't use my PA2 to attenuate; anything less than 6'o clock, and the left side is louder than the right & the right side is staticy.
I would suggest that you email Gary about this. He told me that using it in effect as an attenuator would be a good way of using it since the components are better quality than the mp3 player.

It sounds as though you have a fault on your amp. :-(
post #37 of 92
Quote:
Originally Posted by sumone
I can't use my PA2 to attenuate; anything less than 6'o clock, and the left side is louder than the right & the right side is staticy.

Does sound as if it is faulty, Gary does offer a lifetime guarantee so he will fix it for you, making sure you check your connections, source and so on first.
post #38 of 92
Cheap pots often have volume tracking problems at low volumes. You could send it back and insist that he try multiple pots until he finds one that doesn't have noticeable tracking problems...

As for why Gary recommends setting your mp3 player to 50% volume and reducing the volume on the PA2, it's a common best practice when connecting source to amp. By having the source at a higher volume, you can use a lower gain setting on the amp. As long as you don't cause any clipping on your source, this maximizes the signal to noise ratio in the system. You have to balance clipping and distortion on your source with low volume mis-tracking on the amp's pot. Ideally, your amp would be set to a lower gain setting (2-3x) to allow you to use more of the pot's range as well.

Quote:
Also, having the charger plugged in while playing adds even more noise. Is the noise issue really fixed with the V2?
Looking at the datasheet of the LM4881, it would be wise not to use the amp plugged into the low quality unregulated adapter (as Gary himself called it). These things are insane ripple generators, and with the low PSRR of the LM4881, you would surely hear it.

Now, for an idea about modding: The LM4881's performance suffers a bit due to the low supply voltage from the 2 AA's (2.4v, which is below even the 2.7v minimum recommended supply voltage on the datasheet), so barring Plainview coming out with 1.5v NiMH AA's you might want to think about getting another pair of AA's in there

Or, you could get a 5v linear regulated power like the Elpac WM050-1950-760 or possibly the WM1005-760 or WP1205-760, which would cost you $25-40 depending on availability and order size, which might make you question whether you should just put it towards a better amp.
post #39 of 92
Quote:
Originally Posted by spike33
Found this on ebay and was wondering how it performs compared to a cmoy
http://www.electric-avenues.com/amplifiers.html
The long and short of it is that the sonic performance of the PA2 clearly takes a back seat to cost, battery life, and convenience (rechargeable and includes AC adapter). The cMoy can be designed for higher performance, as there are many amps built on that design with souped-up components. Even a basic cMoy will have a better op-amp than the LM4881 found in the PA2.

The LM4881 op-amp is not a high performance op-amp but is designed for low power applications. Low PSRR at audio frequencies, relatively high distortion and noise levels, but it does operate with supply voltages from 2.7-5.5v, has low current draw, and even has an auto-shutdown feature to maximize battery life. Along with the low voltage supplied by the dual AA batteries, this is probably the weakest link of the PA2.

But ultimately, not many amps can match the price of the PA2, and especially when one considers that it is bundled with an AC adapter and the ability to recharge the batteries while they're still inside the amp.
post #40 of 92
i held out on posting because i wanted to be able to get some listening in with my pocketamp before reviewing and i can say that i am pretty happy with it. i usually either have it hooked from my computer line out to the pocket amp to either my HD515s or my ER-6s and both sounds perfectly good. it was definitly designed with the normal person over the audiophile freak in mind. The fact that i can have this plugged in next to my computer, unplug it, put it in my backpack, use it all day and then come home and plug it in again for a recharge is pretty awesome. i would buy this over a cmoy because of the obivous convienance and the fact that it actually sounds pretty damn sweet and is tiny(it is about 2"x2"x.5") makes it pretty outstanding. however, i do see myself upgrading in the near future since we all get that bug when we start upgrading things and cant stop.

rj

by the way, my amp is #357 and you can check it out on the electric-avenues.com site. I have a picture of it with my etys and my senns.
post #41 of 92
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post #42 of 92
Quote:
Originally Posted by midlife
There is hiss on all phones when cranked. Not as much as ipod or panasonic cdp headphone out cranked, but yes still there. I don't really hear it at all until about 6:00 for grado's and 9:00 for akg 401, both levels are much louder than I would listen to.

I haven't really listened with the ac adaptor, but that that issue seems to have been addressed in this thread.
I received my PA2V2 not long ago, also bought another decent AC adapter. The PA2V2 is a very good amp for the price, no complaints. Service & support is superb My observations :

Depending on type of headphones, the hiss is audible but at different volumes of PA2V2 (assuming you have a regulated/stabilized AC adaptor).

Source : Apple PowerMac G4 headphones out jack (not very good, I know). No audio playing, sound is muted

AC Adaptor : NEWSTAR NS-AC501 Universal AC/DC Adaptor (Stabilized & Regulated)
Input : 100-240VAC, 50/60Hz
Output : 3/4.5/6/7/9/12VDC Selectable
Regulated DC, Max. 9 WATT
Rated Current (mAmp) at 240 VAC : 1500 (3VDC), 1200 (4.5VDC), 1000 (6VDC), 900 (7.5VDC), 800 (9VDC), 700 (12VDC)

Headphones : Grados SR325i (32ohms) & Philips SBC HP800 (32ohms)

Interconnect : 1/8" (Male) to 1/8" (Male), bundled with PA2V2

Rechargeable batteries : GP NiMH 2500 (2450mAh), not fully charged, just got it an hour ago.

Philips HP800
Without any batteries or interconnect plugged in, hiss is present at 6:00 (PA2V2 volume).
Hiss is amplified slightly when interconnect is plugged in, more so when other end of interconnect is connected to audio source (headphone jack).
With the batteries, hiss is only evident at 8:00 (PA2V2 volume)

Grado SR325i
Same as above, except that with batteries, hiss is only evident at 5:00 (PA2V2 volume). You need to strain a bit to try to hear it at 6:00. Batteries reduce the hiss slightly, but it is still there. I guess better headphones bring out the hiss at lower volumes, between my Grados & Philips Not sure about Senns though.

I leave the PA2V2 amp at 5:00 and adjust my computer volume instead. Good thing is, 70% of computer volume is plenty loud with the PA2V2. Without PA2V2, even 80% is not much previously.

I guess that hiss is audible after all, the best you can do is to pop in a pair of NiMH rechargeable batteries (among other things) as I have demonstrated. Are the more expensive amps without hiss? Please share your observations. Thanks.

Cheers,
pokipoki
post #43 of 92

should i get a pocket amp?/problems with etys

This has been a great thread to read, so I thought I'd ask for help.

I recently started investing in better headphones for my ipod/computer, and now have a great trifecta: grado sr-80s, etymotic er-6i's, and sony ex81s. The er-6i's have awesome noise isolation (esp. with foam), but they lack bass and soundstage, so particularly for them, i went on the market for a good but cheap amp.

I went with a Cmoy on ebay, from a very highly regarded seller, but I was disappointed to find that it had a lot of hiss, especially on the etys. He thought that it was defective, so he sent me a new one, with a set gain of 4.3 (instead of the 11 of the first, which made the etys almost too loud on the lowest ipod setting). I got that yesterday, and it still has background hiss - I can hear it most with my etys (16 ohms), and less with the grados and sonys. Plus, it matters which source I'm using - a lot with my powerbook, less but still noticeable with my 4G ipod, and the least with my 2G ipod (still ticking!). But the hiss is getting to me, since I want to use it with my 4G ipod. I went out and got gold 1/8" to 1/8" plugs, which seemed to help some but not too much.

SO - I was thinking about trying out a different amp, like this pocket amp 2, and wanted to get your guys' read on this. I am no audiophile or expert with all the terminology, but I am starting to get pretty discriminating, and definitely don't like the hiss (what's the point of in-ear phones like the etys?). Do you think that a low impedance will always give me hiss in the etys? Would a gain knob on an amp, as with the pocket amp 2 help? Would a pocket amp 2 not boost the bass and soundstage enough? (since it seems like the op chip isn't as good?). Lastly, could burning in the Cmoy help with the hiss, or just the sound quality?

Thanks in advance for your comments!
post #44 of 92
It would help if you linked to the particular amp. I noticed a lot of ebay cmoy sellers have less than ideal wiring and configurations. Also, do you notice hiss without anything plugged into the cmoys input?
post #45 of 92
Quote:
Originally Posted by smessvader
This has been a great thread to read, so I thought I'd ask for help.

I recently started investing in better headphones for my ipod/computer, and now have a great trifecta: grado sr-80s, etymotic er-6i's, and sony ex81s. The er-6i's have awesome noise isolation (esp. with foam), but they lack bass and soundstage, so particularly for them, i went on the market for a good but cheap amp.

I went with a Cmoy on ebay, from a very highly regarded seller, but I was disappointed to find that it had a lot of hiss, especially on the etys. He thought that it was defective, so he sent me a new one, with a set gain of 4.3 (instead of the 11 of the first, which made the etys almost too loud on the lowest ipod setting). I got that yesterday, and it still has background hiss - I can hear it most with my etys (16 ohms), and less with the grados and sonys. Plus, it matters which source I'm using - a lot with my powerbook, less but still noticeable with my 4G ipod, and the least with my 2G ipod (still ticking!). But the hiss is getting to me, since I want to use it with my 4G ipod. I went out and got gold 1/8" to 1/8" plugs, which seemed to help some but not too much.

SO - I was thinking about trying out a different amp, like this pocket amp 2, and wanted to get your guys' read on this. I am no audiophile or expert with all the terminology, but I am starting to get pretty discriminating, and definitely don't like the hiss (what's the point of in-ear phones like the etys?). Do you think that a low impedance will always give me hiss in the etys? Would a gain knob on an amp, as with the pocket amp 2 help? Would a pocket amp 2 not boost the bass and soundstage enough? (since it seems like the op chip isn't as good?). Lastly, could burning in the Cmoy help with the hiss, or just the sound quality?

Thanks in advance for your comments!
I don't know about burning in cmoy chipsets, but I do know that power source matters on the pocket-amp 2. If you use regular akalines or the included ac adapter, there will be some hiss beyond maybe 65-70% of the amp's knob turn. Once you pop in rechargable AA's (as recommended by Gary), the lower voltage seemed to reduce a little static/hiss.

I also keep my mp3 player at 50% volume when using my PA2, and only adjust the amp knob after that. I'm hearing no hiss with the knob up to maybe 80-85%, but I'm usually around 40-50% so know problems here.

I believe Gary has a pair (or more) of etys. You can fire off an email and ask him the same questions above. He's a very nice guy.
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