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Review and Measurements of Massdrop THX AAA 789 Amp

Paul_d

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Hi

Brought this beast! Looks very solid, sound as well :)
Should I plug off it from power (green diode always on when plugged to socket) ?
 

dsnyder0cnn

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Hi

Brought this beast! Looks very solid, sound as well :)
Should I plug off it from power (green diode always on when plugged to socket) ?
Let me measure the power draw from the SMPS while the amp is off. It's probably very small, but I'll let you know what I see (for US 120V)
 

Jimbob54

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I bought my THX AAA 789 back in September 2019 and it has been running 24/7 with no issues at all. Paid $400 for it.
Similar, but mine now makes some nasty noises if the phones are plugged in and I bounce the volume dial off the bottom (far anti clockwise). Not sure what that is but avoiding it is easy.
 

raistlin65

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Rottmannash

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some idiot pouring water over his amp in the sink....
 

Rottmannash

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He just wanted to bring back a clean and fluid sound experience...
isn't that how one retrieves those "liquid mids"?
 

edahl

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Did anyone see the dumpster fire of hate going on on reddit? It reminds me of why I don't go on there anymore.

https://www.reddit.com/r/headphones/comments/qahty8
It's trivial identity formation. People who think purchasing decisions are a personality cannot bear the thought that the entire basis of their identity can be reduced to a $200 amp available on drop. You see this sort of thing in any hobby with a strong gear acquisition element.
 

John B

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A lucky fellow to remember to unplug the device. This type of person has a high likelihood to have modified his grounds to be “audiophile” ; )
 

phoenixdogfan

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Quick question here. I have a THX AAA 789 and a pair of OG HD800s which came with unbalanced cable. I see a great deal more power is available through the balanced outputs than the unbalanced, and I'm wondering if I could tap into that by simply using a balanced to unbalanced cable adaptor or whether I would have to buy an actual 4 pin XLR balanced HD800 headphone cable which is obviously quite expensive. Sennheiser is selling its cable for $375 which is more expensive than this amp which as we know has been priced as low as $200.
 

Jimbob54

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Quick question here. I have a THX AAA 789 and a pair of OG HD800s which came with unbalanced cable. I see a great deal more power is available through the balanced outputs than the unbalanced, and I'm wondering if I could tap into that by simply using a balanced to unbalanced cable adaptor or whether I would have to buy an actual 4 pin XLR balanced HD800 headphone cable which is obviously quite expensive. Sennheiser is selling its cable for $375 which is more expensive than this amp which as we know has been priced as low as $200.
No- you cant plug an unbalanced cable into a balanced amp output with an adapter. You CAN plug a balanced cable into an unbalanced amp output with an adapter.

You can get aftermarket balanced HD800 cables all over ebay/ Ali etc for far far less- just make sure seller / product gets good reviews and lots of them.

Or just use the 1/4 inch output on the 789 which will more than power the HD800

EDIT- looks like you are getting solid answers on this on the HD800 thread.
 
Last edited:

Shoaibexpert

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Seems like after 3 years, one of my THX 789 capacitors is swelling up and needs replacement. Any idea what is the part number I can use to reorder them? I know it's Rubycon.

Also, the pot seemed to be quite scrathy and was making noises so I put in some WD40 only to find it shouldn't be used . Any idea if the pot can be fixed at all or cleaned?

Thanks
 

f78fk

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Seems like after 3 years, one of my THX 789 capacitors is swelling up and needs replacement. Any idea what is the part number I can use to reorder them? I know it's Rubycon.

Also, the pot seemed to be quite scrathy and was making noises so I put in some WD40 only to find it shouldn't be used . Any idea if the pot can be fixed at all or cleaned?

Thanks
It should be this.
16PX3300MEFCG412.5X20
 
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