Thanks for the help but I already packaged it up and have the courier picking it up tomorrow for service/replacement.
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Sorry to hear about that. It really is a good amp. I bought mine almost 2 yrs ago, gently used, for a very good price and have had no problems so far. Iād give it another shot. IMO, it is that good a value. I use it with a DAC and a tube hybrid preamp. Powers all my current (& future) cans very well, speakers too. Versatile.
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I use mine strictly as a speaker amp to power my JBL studio 530s and its great for that use case. Not a huge fan of it as a headphone amp personally, but thatās probably because EI have better headphone amps now.
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I use it with planar headphones (Fostex t50rp mk3ās, he400iās, Ananda, and soon Arya) in conjunction with a tube hybrid preamp and DAC, resistors bypassed. Gives me all the power I need for planars. The tubed pre makes it sound much smoother, the soundstage wider and more delicate. I like the versatility of the system as a whole.
What tube preamp are you using?
An inexpensive one. Aiyima Tube A3 Pro, Amazon. As an experiment, to see if a tube pre could smooth out the a-100 and help with the volume level issue using the amp in bypass mode. Out of the box it showed some potential but was a little sharp sounding. I upgraded tubes and opamps. Everything is nice and smooth now, Iām still using it. $100 total cost for the āprojectā, mods included. As time passes Iāll move on from it to something better but it has itās place for now and I have no real complaints.
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Just to report inā¦ The Hifiman Arya that I got an open-box deal on just came in today. Iāve been listening off and on for most of the day and Iām more impressed the more that I listen. Happy to report that the A-100 drives them very well with the jumpers in. Very, very minimal - to virtually no noise floor hiss even though the Arya is technically a low impedance headphone and I have other components in the signal chain. The extra power makes a dynamic bass foundation to the rest of the cansā sound qualities, IMHO.
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Other than the hd600s and the 600 ohn dt880s, are there other higher impedance
Headphones that can take advantage of the a100. Wothout yanno, busting into flames 
Its my primary use for single-ended, and would like to keep the page 11 mod permanent.
I use the A100(jumpered) to drive (very) high impedance vintage cans from the 70s and 80s I started to collect in the recent months like AKG K240M (600 Ohm)/ K340 / K260, Beyer DT880(old 600 Ohm version), Pioneer SE700, Sennheiser HD414, etc. Many of them are extremely low in sensitivity, single ended and often were meant to be connected to the speaker terminals of your old receiver systems or to their headphone jacks which were more or less directly tabbed to the speaker stages in those days. This use of the speaker outputs is not recommended for modern class D/T balanced speaker amps which do not share a common ground (actually that would kill them both probably) and that is where the A100 steps in.
Some of these cans run also quite well of my DarkVoice OTL tube amp in single ended but some of the driver technologies used are not suited for OTL. As far as possible I modded the phones to balanced connectors (as I did for my āmodernā Beyer DT880/600 Ohm) to run them of the more powerful and cleaner balanced outputs of ānormalā headphone amps (THX-789, ifi ZenCAN, and alike) but still the A100 has a lot more headroom. I do prefer the clarity of the DT880/600(balanced) when driven from my THX amp but some phones can not be converted to balanced or require even more power(!)
The Pioneer SE700 from the 70s for example has piezoelectric drivers which are a capacitive load that requires a lot of voltage swing. If you want to look at it the more common way: its impedance is in the high KILO-Ohm regime for average frequencies. They are single-ended only and run exceptionally well from the A100 (really outstanding electrostatic-like sound plus unexpected bass response on this amp) but I have to crank it up to about 2-3 on the volume pot for normal listening levels while the (modern) DT880/600 are already very loud at 10-11 for comparison.
I also use the speaker outputs of the A100 - just not for speakers. I hooked up a transformer unit (āenergizerā) for an old electret Sennheiser Unipolar2000 to them and plan to add an old SRD-6/SB āenergizerā I just bought on ebay to drive my vintage STAX SR-5 ( I do have a Koss ESP 95x electrostat as well but no amp to drive these old ānormal biasā Stax earspeakers).
TL;DR the A100 turned out to be a really versatile amp which is now an essential part of my setup for vintage cans even if it has not the best sound quality out there.
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Got a new amp back from service. Everything seems good. No peep out of any channel.
On a āfunnyā note, hereās how the box for the new package looked like:
Thatās got to be at least a 1 meter drop.
Honestly was expecting to see bent metal inside. Luckily enough it was double packed and thick polisterene.
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Donāt they come in a doubled up box with thick foam inside?
Should be pretty mail-safe
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Jeez, you have had a crappy experience with them so farā¦I am happy you finally got a properly working unit. Happy Listening and I like your reviews very much! Please keep them up.
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Sorry if this is a silly question, but does the amp have to be turned on to pass the line signal through the line out at the back? I donāt own this and couldnāt find the answer online or in the manual.
Basically was wondering if I could use the line out signal for my headphone amp without turning the A-100 on.
Let me check.
Edit: It just passes through, no matter if it is on or off.
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Thatās really cool, saves a splitter for my DAC output if I get this amp. Many thanks for checking!
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Question for BasX A-100 owners out there. No matter what headphones, with what cable, I plug into the 1/4in headphone out in the front, sound only comes out of the left earcup. Zero sound out of the right one. Tested with multiple headphones and cables. Any ideas? Kinda strange but I know next to nothing about speaker amps.
The amp is probably defective. Is it under warranty?
Besides changing headphone cables, have you tried different rca?
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