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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 231

post #3451 of 3639
Quote:
Originally Posted by robrob View Post
 

The Topping T60 has a TA2022 in it. It has a common, grounded speaker output (both black terminals):

 

Doesn't the TP60 have a pair of bridged TA2022's for the output though? which means not common ground (I might be thinking of another amp though). Either way, the best route is to just get a cable terminated with 4-pin XLR and make an adapter for speaker taps that don't share ground.

post #3452 of 3639
Quote:
Originally Posted by ben_r_ View Post
 


Use in line resistors for attenuation and you wont have any noise.

I'll look into it. Thanks.

post #3453 of 3639
Quote:
Originally Posted by IwasDerp View Post
 

I'll look into it. Thanks.


You can see my DIY here: LINK


Edited by ben_r_ - 4/3/14 at 9:19am
post #3454 of 3639
Quote:
Originally Posted by Velomane View Post
 

 

Did you use the DIY thread as a guide for this project? Also, as a Canadian, I'm curious where you sourced your parts-locally, online? I'm interested in doing something similar to my forthcoming mini-X.

I mostly used this thread and robrobinette's website for inline attenuation.  As for the parts they were sourced from Mouser.ca except for the wire, I had some spare mogami quad.

The plate is quite big and I brought it to a local blacksmith(cost me 40$) for the hole in lieu of buying a couple bits to go through the metal.

post #3455 of 3639
Sorry if I misled people. I couldn't find the circuit diagram and read somewhere on a couple of other websites others were saying the TP60 didn't share a common ground.

My TP60 doesn't hiss. I've got it hooked up to my DAC, an Audio Gd 15.32 which I can control the volume off, I set at high gain but I can use the volume knob to control the output to the TP60. I usually have this at about 11 o'clock. I have the topping at about 10 o'clock. All this is sourced from my PC and that volume is set at about 90%.

I don't hear hissing until the volume pot on the Topping is at 2-3 o'clock but that is deafening
post #3456 of 3639
Quote:
Originally Posted by spurxiii View Post

Sorry if I misled people. I couldn't find the circuit diagram and read somewhere on a couple of other websites others were saying the TP60 didn't share a common ground.
 

 

The TA2022 datasheet specifically states it has single ended outputs (and the schematic posted on the previous page is from the TA2022 datasheet and it shows the negative speaker terminals tied directly to the chip's ground). The input is also single ended.

 

But most of the other Class T TA chip amps have balanced output not tied to ground.


Edited by robrob - 4/3/14 at 4:46pm
post #3457 of 3639

But a few pages later in the datasheet it does show you how to bridge the outputs.

 

Best to ask the manufacturer how the amp is configured and whether it is safe to tie the grounds together. Or just keep everything separate and never worry about it.

post #3458 of 3639

Just wondering has anyone else received any information from Brunk, about the Robinett Box ? Thanks

post #3459 of 3639

Nope not yet. Haven't received any reply to my mails / pm's . Which is very unlike him, hope everything is all right with him.

post #3460 of 3639

I need some help from this thread.  I am using speaker taps on my Denon AVR to drive my headphones.  Alpha Dogs, HE-4, Beyer DT880.  It outputs 125 wpc, and I have the Denon set to power on at -45 db and I adjust the volume up from there, and everything sounds good, black background great sound.

 

I would like to use the speaker taps on my new tube amp (Jolida FX10 10 wpc).  The manufacturer says not to power the amp on without having speakers attached, and there are two sets of speaker taps, 4 ohm and 8 ohm.  I plan to use the 8 ohm taps.  My question is, will 10 watt 10 ohm resistors across each set of L/R speaker taps protect the tube amp transformers from damage?

 

I have been using the speaker taps on my little Ming Da headphone amp to power those same headphones, but I use my Denon AVR Zone 2 output to connect to the tube amp, so I have controlled volume via my remote.  No problems that I know of but I remember reading that using tube amp speaker taps, there should be a load (resistors) across the speaker taps.  I don't require attenuation because I have a gain control on the HP amp set low, kind of like a preamp, and I use the AVR volume control!

 

Can someone here please respond about using tube amplifier speaker taps for Headphones so I know how to do it without damaging the amp?

 

Help is greatly appreciated!

post #3461 of 3639
^The impedance seen by the amp should be around 8 ohms. So a 8-10 ohm resistor should be fine I think..
post #3462 of 3639

Thanks....anyone with comments specific to tube amps and speaker taps?

post #3463 of 3639

Yes, 10ohm 5watt resistors will be fine for your tube amp. I run these 10ohm 10watt resistors when I use headphones on my 40wpc tube amp. Your amp will see right at 8ohms of load with the resistors and headphones connected.

 

RobinetteBoxPanel.jpg

post #3464 of 3639

P.S. Shouldn't it be the combined impedance load of the headphone + resistors that should be close to 8 ohms? Achieving that combination will depend on the headphone's impedance and the resistors used. Low impedance headphones are much easier to work with in this regard. Doing so is especially important when using transformer-coupled tube amps via speaker posts.

post #3465 of 3639
Quote:
Originally Posted by Terja View Post
 

P.S. Shouldn't it be the combined impedance load of the headphone + resistors that should be close to 8 ohms? Achieving that combination will depend on the headphone's impedance and the resistors used. Low impedance headphones are much easier to work with in this regard. Doing so is especially important when using transformer-coupled tube amps via speaker posts.

That's right. If you want more consistent load for all heaphone impedances you should look into robrobs 'preferred resistor network'.

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