VanNeumann
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- Feb 23, 2018
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I know a few members have had the Topping A30 and Dx7/Dx7s. Any thoughts on the sound and build quality of the amps or amp portion of the Dx7/Dx7s?
The TPA6120 basically requires 10 Ohm output impedance. From the tech docs: "The series output resistor should be between 10Ω and 100Ω." In fact, most of the examples use a 39.2 Ohm output resistor.Oh , I don't have one. There are pictures of the a30's pcb on the topping website. Yea, it has 10 ohm output impedance on the normal headphone jack and 20 ohms on the xlr connection.
I know a few members have had the Topping A30 and Dx7/Dx7s. Any thoughts on the sound and build quality of the amps or amp portion of the Dx7/Dx7s?
These days, there are many high quality, competitive priced amps of both discrete and IC topologies with output impedance <1 ohms. Topping basically slaps on the TPA6120's and calls it a day. This results in their amps not being suitable for headphones under 80 ohms in SE and 160 ohms in XLR. Otherwise, your dynamic headphones will be overdampened in swaths of frequencies (and not others) and sound flabby. Planar impedance are usually flat on the frequency domain, so you won't get this effect, but planar impedance are usually low (~20-40 ohms), which, say, paired with an output impedance of 20 ohms XLR means that up to half of the amp's output energy is dissipated before reaching the headphones. This overdampening effect across all frequencies results in anemic attack and long impulse decay at the signal level. How this signal characteristic translates to what you hear depends on the mechanical aspects of your transducer and earcups.
For me, I would never spend my own hard-earned moola on solid state amps that have more than 2 ohm output impedance, and I prefer something much less than 1. This is why I personally would never recommend the DX7 or the A30. If you like Topping for their DACs, the D10, 30, and 50 are great value DACs.
Junki, I agree with you on th issu s with higher output impedance amps. What are some of the other low impedance amplifiers that you like?
So, the only amps I've found with both people who've heard lots of equipment saying they sound nice and measurements to support good technical implementation are the Schiit Jotunheim and the now incredibly unavailable Alex Cavalli Liquid Crimson. I haven't seen measurements for the Rupert Neve RNHP, but Jude put it to use for a stint as their official amp in their headphone measurement setup because he said it measured so well. I have high confidence that all the THX AAA amps will blow everything out of the water on the measurement side, but I haven't heard anything about what the affordable ones (Monoprice and Massdrop) sound like because they're not released.
That's all I got.
Personally, I've been looking for a new DAC and AMP. I'm still undecided between the SDAC and the D50 as my DAC, and I'm at a loss for my amp. I'd choose the Jotunheim, but if I were to get a balanced amp, I'd need it to be bridged so I can use the RCA inputs, and the Jotunheim AFAIK is not bridged.
Yea its a 0 impedance amp too.Hi Junki, how about the Arcam rhead from your signature? I guess it should have a relatively low impedance too?
Can't wait for that A30 review
I personally love my A30 and use it like all day every day.
Wow what a tease you areI am sorry I keep forgetting to test the A30. To make up a bit for it, here is a quick comparison against JDS O2:
View attachment 14508
As you see, it has more power but more noise. Distortion is the same as O2 except that the A30 has much more power.
Alas, it has high output impedance (27 ohms). So needs a headphone with high impedance or flat frequency response. Otherwise the frequency response of the headphone will be modified which may be for the better or worse.
Yes I did. Is the larger jack different?Did you use the small headphone output for those measurements? That one is supposed to be 30 ohms.
The larger one is 10ohm like the DX7.Yes I did. Is the larger jack different?