[Pharmaboy]

Hmm. Apparently the knob is so big that there are problems with the shaft, and you have to play around with the shaft a bit to get the knob nice and firm.

Never heard that before; also never experienced it in 5 years of ownership.

Then again, Fried really knows his stuff. Maybe I've never experienced this because my V281 has the remote-controlled, 128-step pot. I almost never turn it by hand, only by remote.

So if this pot is a problem, I need more problems just like it...

 

[Elegiac]

Never heard that before; also never experienced it in 5 years of ownership.

Then again, Fried really knows his stuff. Maybe I've never experienced this because my V281 has the remote-controlled, 128-step pot. I almost never turn it by hand, only by remote.

So if this pot is a problem, I need more problems just like it...

So you have one of the hugest knobs around, but you never touch it?
Sorry if this sounds nitpicky, but isn't the whole point of having a massive, thick knob, in the satisfaction of physically using it?

 

[inscythe]

So the sound is similar to A90D, able to compare your experiences with the H300 more? I also have a D300 at home so I might get it during year end sales.

Like I said, my A90D is still with the retailer for repair, so can't directly A/B. However, when I paired it with my D90SE, it sounds remarkably similar to when I have the full A90D-D90SE stack. So, based on my limited testing, the noticeable difference in sound signature between the stack is likely from the DAC rather than the amp. I would treat this as a way cheaper alternative A90 or A90D. That said, with its sudden failure, the A90D has lost my trust, and even when I get back my A90D or a new replacement unit, it'll probably go up for sale. I think pure amp should stay in analog domain and should require no firmware updates, which is partially the reason why I went with H300.

However, one thing of note. I can drive my HE6SE V2 with low gain on A90D 60/99, while with H300, I need mid gain (A90D only has 2 gain levels and H300 has 3, so there should be some scaling difference).

 

[IamInnocentX3]

I see, thanks for the heads up. S.M.S.L's budget HO100 amp with low gain never impresses me, it lacks bass texture for my earbuds so I usually go for mid or high gain. From the sound profile and pictures you described, I guess H300 might work for me? The features given are a steal, but the topology of stacking 64 opamps together is weird. Still, can't judge what works and what not.

HE6se requires tons of power to be able to fully driven. I just knew that the low gain on A90D is just equal to mid-gain of the H300 because of the 0db range, guess the HE6se doesn't need that expensive equipment for the sound to be opened up.

Condolences for your A90D. Hopefully it will go better from here on out.

 

[inscythe]

HE6se requires tons of power to be able to fully driven. I just knew that the low gain on A90D is just equal to mid-gain of the H300 because of the 0db range, guess the HE6se doesn't need that expensive equipment for the sound to be opened up.

For sure. HE6SE can get to a comfortable loudness on midrange amps, but to get the optimal sound signature, it does need some extra juice, but not as crazy as people think. Modern amps are very efficient.

Condolences for your A90D. Hopefully it will go better from here on out.

Yeah, I really liked it... But trust lost is hard to regain indeed. Also, I like matching stacks, so having Rohm DAC in D300 is also something new for me. Hopefully this will last longer than my previous stack.

 

[NickT23]

So the sound is similar to A90D, able to compare your experiences with the H300 more? I also have a D300 at home so I might get it during year end sales.

YES, sounds exactly the same when you do true a/b. 0126055523, can contact my number for fun if interested.

 

[Pharmaboy]

So you have one of the hugest knobs around, but you never touch it?
Sorry if this sounds nitpicky, but isn't the whole point of having a massive, thick knob, in the satisfaction of physically using it?

Maybe that would be the whole point if the V281 was within easy reach of my office chair. But it's about 4 ft away, just out of reach, so adjusting it by hand really isn't convenient. Thus the remote.

By contrast, my "side system" (~6 ft away from the main desktop system, and immediately to the left of my chair) is entirely within easy reach (SPDIF converter; DAC; two headphone amps), so I adjust everything by hand. The DAC (Audio GD R2R-11 MK2) has a larger-then-usual stepped pot that is a real pleasure to rotate...

 

[Elegiac]

I'd love to know what those op-amps are. And read some more feedback/reviews.

 

[leeperry]

I'd love to know what those op-amps are. And read some more feedback/reviews.

 

[dunring]

I just got an H300 and a chance to compare it to one of the A30Pro's I've been using the last few weeks. The sound reminded me right away of the Sabaj A20H which is 1/3rd the price, has digital volume control for perfect channel matching, and doesn't run as warm. The design is sturdy and vented on the side, it's warm but no more so than the A30Pro. I've had a Gustard X26 Pro which runs hot, these aren't even close to that.
The H300 sounds fine, if you have an A30Pro I wouldn't suggest switching though. The volume wheel on this was scratchy/grindy after 3 oclock and felt like it got stuck towards the end. Will be sending this model back, but at least I could do a comparison to the A30Pro while having them both. The switches are fine except the gain switch. I learned right away to turn the volume wheel down before snicking the gain switch, because it's ridiculously easy to overshoot into high gain when aiming for medium. I was able to measure channel balance and it never deviated more than .2db and most times it was .1db or even. I use a 3.5mm male to male cable into the line in on the sound card, and on digital amplifiers both channels are a perfect match through the range, so I think it's fairly accurate. Every model is different, but it's within factory spec.



It's a simple design, transparent like most amplifiers out there today, and I'm sure if it gets measured it'll do well. This doesn't have venting on top, so if you have a cat, at least you'll never have to wonder where they're sleeping ever again. The volume wheel is small but not as annoying as I thought it would be (despite this one is defective like several of the Schiit Magni's I've had over the years with the scratchy/grinding problem).

If you get one, I'd order some thick round rubber feet on Aliexpress or Amazon to give it some airflow underneath. These are the ones I use. Just little speaker feet, but small enough to fit under an amplifier too. They come with 3M sticky pads to attach them.




Comparison:
Sabaj A20h has digital volume, 1/3 the price, almost exact same sound, less power (but still enough for the He6se with a 5 volt DAC). They're becoming hard to find, and the connectors on the back are annoying, also the XLR on the back are upside down, so you need a 3ft cable to twist enough usually.
The A30Pro is pretty evenly matched for power, better controls, and much better volume wheel. The vents are a dust magnet for pets. Also it has the same power on all headphone jacks, the H300 has different gains on SE and balanced. In low gain it's amazing with sensitive IEMs (95 on the 50mv test, completely silent noise floor).
The H300 gain switch is a recipe for disaster if you have easily blow-uppable headphones like the DT900/700 Pro X and use the switch often. Both the A30Pro and this will raise a 10x12 room temperature by 1 degree F if you leave them on all the time. Both surface temperatures measure with a laser thermometer too close to call on the hotspots.

Personally, I would save money and get the Sabaj A20H since they sound identical and perfect channel matching. The A30Pro is a sure thing as long as you don't have dust issues.
The best headphone amplifier stacks I've heard are my current SMSL SP400/M400 and also the Topping A70Pro/D70Pro Octo I just put together this month. I'd either scale back to the A20H or save up for the SP400 or A70Pro and sit either on the SMSL DL200 which is my permanent DAC, since it's big enough to sit almost any amplifier on. The H300 is a good amplifier in a crowded field, there's just no standout feature that makes it a must buy. It looks really nice on the SMSL DL200, but at this price so does a used Topping A90. Even the Topping L70 would be a great choice at the right price in comparison.

For myself, I've got a Topping A70Pro coming next week for $362 during the Aliexpress sale running through March 27th. It's going to be my permanent amplifier at that price with the DL200 under it.
In case you miss it or need to save up, the next ones are:
June 12th Summer Sale
Brand Shopping Week (August 18-21)
Then Singles day November 11
Black Friday Nov 20th

Those are the really big discount sales each year, the others are pretty minor for discounts compared to those.

The H300 is a nice amplifier, but you won't hear anything you likely haven't heard before. The headroom is great if you actually need it, but the thermals might be an issue for some unless you love all day warm coffee without having to go heat it up... I also have the Topping A50 III / D50 III stacking coming next week, will write up impressions when I get them to compare value for money and if the built in parametric EQ the DAC has works well.