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Review and Measurements of Massdrop THX AAA 789 Amp

Rottmannash

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I have a question. I've had the 789 hooked up to an E30 which is RCA so was able to use the RCA outs to external powered speakers. I've just received my new Toppng D10 Balanced and now I can't get any output from the RCA outs. Is this normal? Have I lost that ability by using the D10 B?
 

gvl

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I always thought they are only pass through outputs for RCA inputs.
 

Jimbob54

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Anyone else get a flubbing popping/crackle in one or both cups when you bump the volume knob to zero? No noises at all before you hit the physical bottom but then pops etc when you do.
 

Rottmannash

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Anyone else get a flubbing popping/crackle in one or both cups when you bump the volume knob to zero? No noises at all before you hit the physical bottom but then pops etc when you do.
I haven't.
 

Veri

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I have a question. I've had the 789 hooked up to an E30 which is RCA so was able to use the RCA outs to external powered speakers. I've just received my new Toppng D10 Balanced and now I can't get any output from the RCA outs. Is this normal? Have I lost that ability by using the D10 B?
Yeah the RCA passthrough only works if RCA is connected I'm afraid.
 

Paul_d

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is this amplifier still good for now for $250-300 ???
found it new on local bargain market... worth to buy today ?
 

AVKS

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oh, good news... but performance of this amp still on top?

With respect to what? It was already well into the realm of inaudible distortion with large quantities of power, so while others have managed to squeeze out a few less dB of noise or a bit more juice it's pretty irrelevant IMO. $200 for this level of performance and feature set is right on the mark IMO. I paid $300 for mine 18 months ago and am still completely satisfied.
 

phoenixdogfan

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oh, good news... but performance of this amp still on top?
It's an endgame amp with gobs of power and gain switch ability, so it can drive anything from IEMs (b/c of its very low noise floor, to power hungry dynamic and planars. The minute difference in SINAD between it and some of the latest and greatest will be inaudible.

And for $200? I paid $450 for mine around 18 months ago.
 

mmichii

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I have an early version of this amp and its just garbage. It already has issues with popping/crackling on the volume pot and 3 of 5 relays are beginning to fail. I hear this crack/arcing type noise when i turn the gain switch. I hear it coming from the pcb. The relays are relatively easy to fix but one of them is near the faceplate and since the volume knob and gain knob are permanently attached i'm probably gonna have to use hot air to get that relay. But because of its proximity to the volume pot i hope i can shield it enough so it isn't damaged (coin as heat sink?). It shouldn't be having all these problems already. All my other amps including the magni's work just fine and they're older. I will attempt the repair but am afraid that i will cause damage to adjacent components replacing the one relay. As insurance i'm ordering a l50 to match my e50. i loved this amp when i first got it but now its just looking like it will be a doorstop.
 

zepplock

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I have an early version of this amp and its just garbage. It already has issues with popping/crackling on the volume pot and 3 of 5 relays are beginning to fail. I hear this crack/arcing type noise when i turn the gain switch. I hear it coming from the pcb. The relays are relatively easy to fix but one of them is near the faceplate and since the volume knob and gain knob are permanently attached i'm probably gonna have to use hot air to get that relay. But because of its proximity to the volume pot i hope i can shield it enough so it isn't damaged (coin as heat sink?). It shouldn't be having all these problems already. All my other amps including the magni's work just fine and they're older. I will attempt the repair but am afraid that i will cause damage to adjacent components replacing the one relay. As insurance i'm ordering a l50 to match my e50. i loved this amp when i first got it but now its just looking like it will be a doorstop.

Just because you have an issue with your does not mean it's garbage. It works fine for lots of other people.
Use warranty, etc.
 

dsnyder0cnn

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Hi THX AAA 789 owners…I've had my amp for nearly a year and still love it. Sadly, I've started to hear quite a bit of static when making volume adjustments. It started in the left channel, but now I'm hearing it in both. I have not observed significant channel imbalance issues once I settle on a volume setting, but the increasing static is disconcerting.

I have tried just working the volume knob back and forth, and with enough rotations, that seems to reduce the static. However, when I come back to the amp the next day, the static is back. I've reached out to Drop support to see if this is covered under warranty. I could easily buy another unit (missed the $199 sale, but the $239 price is still great). However, if this issue is a design flaw that affects many units, I may find myself in the same situation 8-12 months from now.

I'd love to get a sense from this community about how common this issue is. I'm not using my amp in a particularly dusty environment, but even if I were, I'd expect the pot to be sufficiently sealed to protect itself. This is my only gripe with this amp. It's a lovely piece that's destined to become a classic…assuming a noisy pot does not spoil it. Thanks.
 

AVKS

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Hi THX AAA 789 owners…I've had my amp for nearly a year and still love it. Sadly, I've started to hear quite a bit of static when making volume adjustments. It started in the left channel, but now I'm hearing it in both. I have not observed significant channel imbalance issues once I settle on a volume setting, but the increasing static is disconcerting.

I have tried just working the volume knob back and forth, and with enough rotations, that seems to reduce the static. However, when I come back to the amp the next day, the static is back. I've reached out to Drop support to see if this is covered under warranty. I could easily buy another unit (missed the $199 sale, but the $239 price is still great). However, if this issue is a design flaw that affects many units, I may find myself in the same situation 8-12 months from now.

I'd love to get a sense from this community about how common this issue is. I'm not using my amp in a particularly dusty environment, but even if I were, I'd expect the pot to be sufficiently sealed to protect itself. This is my only gripe with this amp. It's a lovely piece that's destined to become a classic…assuming a noisy pot does not spoil it. Thanks.
This type of thing can happen to literally anything with an analog volume pot, assuming yours is just a bit dirty/oxidized. A little bit of contact cleaner and problem solved, even if it needs to be done every year or two (depending on your use and environment).

There could be more to it than that of course but I'd bet a quick cleaning takes care of it.
 
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