TA-100 Headphone jack

[novisnick]

I was just watching a YouTube video with Big Dan talking about the BasX line. After talking about the A-100 which we know we can use a jumper to get much more power for the headphones. Next Dan introduced the TA-100 and stated that the amp section was basically the amp of the A-100.
My question, can we use a similar jumper it the TA-100 as used in the A-100 for our headphones?
That would be so cool!

@keithl ? 
lonnie ?

anybody? Thanks

               

[garbulky]

Not in the same way. The current TA-100 headphone amp is a LOT weaker than the A-100 and is driven by a separate circuit than the speaker outputs.
The A-100's headphone output comes directly from the speaker output though some internal modifications have been done to make it more headphone friendly.
Before the A-100 had that jumper system and a headphone jack, people did use the old versions of the A-100 as a headphone amp. They used all sort of adapters and resistors on the speaker output taps to drive the headphones. Emotiva did modifications to allow the speaker output to be routed to the headphone output for the new A_100.

[novisnick]

Jun 22, 2018 21:40:57 GMT -5 garbulky said:

Not in the same way. The current TA-100 headphone amp is a LOT weaker than the A-100 and is driven by a separate circuit than the speaker outputs.
The A-100's headphone output comes directly from the speaker output though some internal modifications have been done to make it more headphone friendly.
Before the A-100 had that jumper system and a headphone jack, people did use the old versions of the A-100 as a headphone amp. They used all sort of adapters and resistors on the speaker output taps to drive the headphones. Emotiva did modifications to allow the speaker output to be routed to the headphone output for the new A_100.

Is this fact or a guess? Did you watch the video comparison? So your saying there’s another amp in the TA-100 just for the headphones? Even though plugging them in will bypass the speaker outputs?

[garbulky]

Jun 22, 2018 21:46:45 GMT -5 novisnick said:

Jun 22, 2018 21:40:57 GMT -5 garbulky said:

Not in the same way. The current TA-100 headphone amp is a LOT weaker than the A-100 and is driven by a separate circuit than the speaker outputs.
The A-100's headphone output comes directly from the speaker output though some internal modifications have been done to make it more headphone friendly.
Before the A-100 had that jumper system and a headphone jack, people did use the old versions of the A-100 as a headphone amp. They used all sort of adapters and resistors on the speaker output taps to drive the headphones. Emotiva did modifications to allow the speaker output to be routed to the headphone output for the new A_100.

So your saying there’s another amp in the TA-100 just for the headphones? Even though plugging them in will bypass the speaker outputs?

yes

[novisnick]

Jun 22, 2018 22:04:59 GMT -5 garbulky said:

Jun 22, 2018 21:46:45 GMT -5 novisnick said:

So your saying there’s another amp in the TA-100 just for the headphones? Even though plugging them in will bypass the speaker outputs?

yes

Didn’t realize! Hmmmm,,,,,,

Damb shame,,,,,,snicker,,,,,,snicker,,,,,

[garbulky]

TA-100
Analog Performance (headphone)
Output Power:
8 Ohms: 23 mW / channel.
33 Ohms: 90 mW / channel.
47 Ohms: 127 mW / channel.
150 Ohms: 145 mW / channel.
300 Ohms: 114 mW / channel.
600 Ohms: 75 mW / channel.
If you look at this output 114 mw is actually pretty good at 300 ohms. It also shows that the output impedance of the headphone amp section is pretty high as 300 ohms obtains the higher output.

Compare to the A-100
Power Output (headphone output; normal mode, jumpers not engaged):
8 Ohms: 60 mW / channel
33 Ohms: 200 mW / channel
47 Ohms: 250 mW / channel
150 Ohms: 430 mW / channel
300 Ohms: 440 mW / channel
600 Ohms: 350 mW / channel

Power Output (headphone output; direct drive mode)
(requires internal jumper; USE WITH CAUTION):
8 Ohms: 50 watts / channel
33 Ohms: 12 watts / channel
47 Ohms: 8.5 watts / channel
150 Ohms: 2.6 watts / channel
300 Ohms: 1.3 watts / channel
600 Ohms: 0.6 watts / channel

[novisnick]

Jun 22, 2018 22:52:08 GMT -5 garbulky said:

TA-100
Analog Performance (headphone)
Output Power:
8 Ohms: 23 mW / channel.
33 Ohms: 90 mW / channel.
47 Ohms: 127 mW / channel.
150 Ohms: 145 mW / channel.
300 Ohms: 114 mW / channel.
600 Ohms: 75 mW / channel.
If you look at this output 114 mw is actually pretty good at 300 ohms. It also shows that the output impedance of the headphone amp section is pretty high as 300 ohms obtains the higher output.

Compare to the A-100
Power Output (headphone output; normal mode, jumpers not engaged):
8 Ohms: 60 mW / channel
33 Ohms: 200 mW / channel
47 Ohms: 250 mW / channel
150 Ohms: 430 mW / channel
300 Ohms: 440 mW / channel
600 Ohms: 350 mW / channel

Power Output (headphone output; direct drive mode)
(requires internal jumper; USE WITH CAUTION):
8 Ohms: 50 watts / channel
33 Ohms: 12 watts / channel
47 Ohms: 8.5 watts / channel
150 Ohms: 2.6 watts / channel
300 Ohms: 1.3 watts / channel
600 Ohms: 0.6 watts / channel

Lets put lonnie  to work! He hasn’t anything better to do! 😋

[KeithL]

It's a fact.

In most vintage equipment the headphone output was derived from the main amplifier outputs - through a series resistor or voltage divider.
How much power you get with this arrangement depends on the value of the resistors used, and the impedance of your headphones.
However, there are drawbacks to this output topology.
In most older equipment, the main speaker outputs are a little noisy for use with headphones, and have a little too much distortion - especially at very low output levels.
(And these limitations are a lot more noticeable with headphones than with speakers.)

Virtually all modern equipment, including the TA-100, and all of our other products, uses a separate little amplifier just for the headphone output.
These range from a simple circuit with a few transistors, to a more or less normal op-amp, to specialized headphone amplifiers.
Most of these dedicated headphone circuits are pretty quiet, and the distortion is quite low, but they vary considerably in terms of how much power they put out.
Also, because they don't use a series dropping resitor, they have a relatively low output impedance, and don't interact very much with the impedance of various models of headphones.
We use several different headphone amps in different pieces of equipment like the TA-100.
They all sound good, with very little noise or distortion, and deliver enough power to run typical headphones of average efficiency very well.

The BasX A-100 is special because it uses the same arrangement as vintage equipment - with the headphones powered from the main output via dropping resistors.
With this arrangement you get a lot more voltage - which works especially well with high impedance headphones.
It also provides plenty of power for low impedance headphones.
We avoided the drawbacks of this arrangement in vintage equipment by designing the main outputs on the A-100 to be much quieter and cleaner than in vintage equipment.
Because the output impedance is rather high - 220 Ohms on the A-100 - the amplifier does interact with the impedance of your headphones to some degree.
This means that, when you connect headphones to the A-100, they'll sound more like they do when you connect them to vintage equipment - minus most of the flaws.
It also means that many headphones will sound slightly different when you connect them to the A-100 than when you connect them to other equipment.
This is with the JUMPERS OUT.

When you install the jumpers, they bypass the dropping resistors, and connect your headphones directly to the main outputs.
This is the recommended arrangement with certain few low efficiency headphones - like certain electrostatics and certain low efficiency planars.
It also works really great with high impedance headphones, giving you lots of damping, and plenty of voltage to drive them really well.
You can also use this arrangement with low impedance headphones, but you have to be VERY careful...
You'll get lots of damping, and plenty of power, but the noise floor may be a bit high, and the gain will be VERY high.
That means that you'll be using the volume control way down near the bottom of its range... and you CAN easily blow out your headphones - and your ears - if you turn it up too high.
(if you use this arrangement a lot you may prefer to put 12 dB fixed attenuators in line with the inputs of the A-100.)

You also have to be REALLY careful when switching between headphones if you run the A-100 with the jumpers in.
With the JUMPERS IN, a Volume setting that's just comfortable with high impedance headphones can be downright dangerous with low impedance models.
So be VERY SURE that you turn the Volume ALL THE WAY DOWN when switching from high impedance headphones to low impedance models...
And ALWAYS start playing music with the Volume control all the way down when you're using low impedance headphones with the A-100 with the jumpers out.

The A-100 is currently the only piece of equipment we have with this type of headphone outputs... and the only one with this sort of jumpers.
(The headphone amps on the DC-1 had jumpers, but they served a very different purpose... they allowed to to select a slight bump of about 1 dB around 50 Hz.)

Jun 22, 2018 21:46:45 GMT -5 novisnick said:

Jun 22, 2018 21:40:57 GMT -5 garbulky said:

Not in the same way. The current TA-100 headphone amp is a LOT weaker than the A-100 and is driven by a separate circuit than the speaker outputs.
The A-100's headphone output comes directly from the speaker output though some internal modifications have been done to make it more headphone friendly.
Before the A-100 had that jumper system and a headphone jack, people did use the old versions of the A-100 as a headphone amp. They used all sort of adapters and resistors on the speaker output taps to drive the headphones. Emotiva did modifications to allow the speaker output to be routed to the headphone output for the new A_100.

Is this fact or a guess? Did you watch the video comparison? So your saying there’s another amp in the TA-100 just for the headphones? Even though plugging them in will bypass the speaker outputs?

[novisnick]

Jun 22, 2018 23:52:10 GMT -5 KeithL said:

It's a fact.

In most vintage equipment the headphone output was derived from the main amplifier outputs - through a series resistor or voltage divider.
How much power you get with this arrangement depends on the value of the resistors used, and the impedance of your headphones.
However, there are drawbacks to this output topology.
In most older equipment, the main speaker outputs are a little noisy for use with headphones, and have a little too much distortion - especially at very low output levels.
(And these limitations are a lot more noticeable with headphones than with speakers.)

Virtually all modern equipment, including the TA-100, and all of our other products, uses a separate little amplifier just for the headphone output.
These range from a simple circuit with a few transistors, to a more or less normal op-amp, to specialized headphone amplifiers.
Most of these dedicated headphone circuits are pretty quiet, and the distortion is quite low, but they vary considerably in terms of how much power they put out.
Also, because they don't use a series dropping resitor, they have a relatively low output impedance, and don't interact very much with the impedance of various models of headphones.
We use several different headphone amps in different pieces of equipment like the TA-100.
They all sound good, with very little noise or distortion, and deliver enough power to run typical headphones of average efficiency very well.

The BasX A-100 is special because it uses the same arrangement as vintage equipment - with the headphones powered from the main output via dropping resistors.
With this arrangement you get a lot more voltage - which works especially well with high impedance headphones.
It also provides plenty of power for low impedance headphones.
We avoided the drawbacks of this arrangement in vintage equipment by designing the main outputs on the A-100 to be much quieter and cleaner than in vintage equipment.
Because the output impedance is rather high - 220 Ohms on the A-100 - the amplifier does interact with the impedance of your headphones to some degree.
This means that, when you connect headphones to the A-100, they'll sound more like they do when you connect them to vintage equipment - minus most of the flaws.
It also means that many headphones will sound slightly different when you connect them to the A-100 than when you connect them to other equipment.
This is with the JUMPERS OUT.

When you install the jumpers, they bypass the dropping resistors, and connect your headphones directly to the main outputs.
This is the recommended arrangement with certain few low efficiency headphones - like certain electrostatics and certain low efficiency planars.
It also works really great with high impedance headphones, giving you lots of damping, and plenty of voltage to drive them really well.
You can also use this arrangement with low impedance headphones, but you have to be VERY careful...
You'll get lots of damping, and plenty of power, but the noise floor may be a bit high, and the gain will be VERY high.
That means that you'll be using the volume control way down near the bottom of its range... and you CAN easily blow out your headphones - and your ears - if you turn it up too high.
(if you use this arrangement a lot you may prefer to put 12 dB fixed attenuators in line with the inputs of the A-100.)

You also have to be REALLY careful when switching between headphones if you run the A-100 with the jumpers in.
With the JUMPERS IN, a Volume setting that's just comfortable with high impedance headphones can be downright dangerous with low impedance models.
So be VERY SURE that you turn the Volume ALL THE WAY DOWN when switching from high impedance headphones to low impedance models...
And ALWAYS start playing music with the Volume control all the way down when you're using low impedance headphones with the A-100 with the jumpers out.

The A-100 is currently the only piece of equipment we have with this type of headphone outputs... and the only one with this sort of jumpers.
(The headphone amps on the DC-1 had jumpers, but they served a very different purpose... they allowed to to select a slight bump of about 1 dB around 50 Hz.)

Jun 22, 2018 21:46:45 GMT -5 novisnick said:

Is this fact or a guess? Did you watch the video comparison? So your saying there’s another amp in the TA-100 just for the headphones? Even though plugging them in will bypass the speaker outputs?

Thank you for the in depth explanation of my query. Most greatfull!