Massdrop x THX AAA™ 789 Linear Amplifier - Impressions Thread
Aug 15, 2018 at 12:33 AM Post #151 of 2,613
i went ahead and ordered a second one im hoping this is a nice as it seems. ill use one at my office and the other with my full complete massdrop stack (so far every product in the housing style) for the price this thing sounds like it may be a killer lower priced amp. i think ill be fine with the change to the gain i dont know though i like both options lol would have been killer just to add the negative option along with the others and adjust the cost a bit.
 
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Aug 15, 2018 at 6:02 AM Post #152 of 2,613
Hi UFO. The 789 has tons of gain and will still go nearly to clipping with a 2 V DAC. What's your DAC/source rms voltage? And do you use TRS or XLR-4 headphone connection?

My DAC is 3v from the SE outputs, 6v from the XLR, but it can be turned down. I'd be using the 4 pin XLR output. I was thinking of using the amp with really hard to drive headphones, so the high gain was attractive. My old amp had +24db gain as well.
 
Aug 15, 2018 at 6:16 AM Post #153 of 2,613
My DAC is 3v from the SE outputs, 6v from the XLR, but it can be turned down. I'd be using the 4 pin XLR output. I was thinking of using the amp with really hard to drive headphones, so the high gain was attractive. My old amp had +24db gain as well.
I recommend using your 6V XLR output (bal XLR is always better) and setting the 789 amp to 0dB gain. Then you'll achieve 6V from amp TRS or 12V from amp XLR4. Yes that's 1.3dB less than the full 7/14V amp clean capability, but will give you super clean SNR. And it will be ridiculously loud.
 
Oct 25, 2018 at 5:30 AM Post #156 of 2,613
I got mine on Tuesday and been enjoying the dead quiet aspect and amazing speed on my Auteur's. I having issue with using the balanced XLR input getting a ground hum and not knowing if these new custom interconnect cables have a wiring issue or a problem on outputs on my Topping DX7S . I ordered a pair of XLR interconnects from amazon to see if I still have a ground loop hum. I used high gain on my Auteur's and was at 10-1 o'clock volume position and that was plenty loud.

The amp is much heavier then I thought and it is put together very well for a $350 amp.

The amp shipped from New Jersey and I live in Ohio.
 
Oct 25, 2018 at 10:55 AM Post #157 of 2,613
Still waiting for mine to be delivered. Massdrop uses a fleet of giant tortoises to send out their packages.
 
Oct 25, 2018 at 12:26 PM Post #159 of 2,613
Mine is scheduled for tomorrow.
Edit: actually out for delivery today. Originally scheduled for two days from now. Woohoo!

Yea, mine was too. I'll hook it up tonight when I get home!
 
Oct 25, 2018 at 9:24 PM Post #161 of 2,613
Got my THX AAA 789 delivered today.

Unfortunately I can't get the unit to power on at all. Went to hook it up and I'm pretty sure the power button is defective. It won't "catch" when you depress it. It just pops right back to it's initial resting place.

Looks like I'll have to wait a little longer... *sigh*
 
Oct 25, 2018 at 10:00 PM Post #162 of 2,613
Got my THX AAA 789 delivered today.

Unfortunately I can't get the unit to power on at all. Went to hook it up and I'm pretty sure the power button is defective. It won't "catch" when you depress it. It just pops right back to it's initial resting place.

Looks like I'll have to wait a little longer... *sigh*
Bummer . I guess I am lucky mine is working .
 
Oct 25, 2018 at 10:01 PM Post #163 of 2,613
Got my THX AAA 789 delivered today.

Unfortunately I can't get the unit to power on at all. Went to hook it up and I'm pretty sure the power button is defective. It won't "catch" when you depress it. It just pops right back to it's initial resting place.

Looks like I'll have to wait a little longer... *sigh*

The switch doesn't catch, its just a button because it has an auto off setting. Make sure its plugged in properly, and then just fully depress the button, you should get a teeny tiny little red led in the middle of the amp that turns white after a second.
 
Oct 25, 2018 at 10:07 PM Post #164 of 2,613
The switch doesn't catch, its just a button because it has an auto off setting. Make sure its plugged in properly, and then just fully depress the button, you should get a teeny tiny little red led in the middle of the amp that turns white after a second.

Ah, thanks. That makes sense.

Well, looks like it's just DOA then. Or possibly the power supply? I might try to test it.
 
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Oct 25, 2018 at 10:19 PM Post #165 of 2,613
Got my THX AAA 789 delivered today.

Unfortunately I can't get the unit to power on at all. Went to hook it up and I'm pretty sure the power button is defective. It won't "catch" when you depress it. It just pops right back to it's initial resting place.

Looks like I'll have to wait a little longer... *sigh*
Mine is partially borked, too. Often, pressing the button doesn't do anything. Sometimes, toggling the auto off setting helps and the next time the button will turn the unit on, and can turn it off again before refusing to work again. Sometimes, disconnecting and reconnecting the power supply helps, too. Not really consistent.
 

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