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wyattd
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Aug 16, 2018

T4S Power supply

I have a T4S mixer and the Bose recommended power supply. I am currently powering this with a portable lithium ion battery pack (Base S360 42000 Mha) which can be solar powered. This produces a modified sine wave AC connection which appears to work OK and power the mixer for several hours. The T4S feeds a Bose S1 Pro using its internal battery pack.

However I have a question on whether a modified sine wave battery generator can damage the T4S or its Power supply brick?

i also find that if I use the generator on the T4S but have the S1 connected to the house mains that noise is introduced into the signal. I find that odd as surely the Bose power brick is converting the modified sine wave generated AC into 18v +/- Dc used by the T4S and it was my understanding that DC does not generate ground loop noise?

Finally I wonder whether the AC to DC  conversion could be avoided by using a direct 18v DC source such guitar pedal power supplies?

Thanks for any information pointers on these issues.

David

 

3 REPLIES 3
ST - Pro
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May 11, 2020

Re: T4S Power supply

Hi, David,

I'm stepping in for the Bose Forum Admin here.

Thank you for your questions.  We have to start off by saying that using a power source other than AC Mains for the ToneMatch Power Supply is not supported. 



David Wyatt posted:

I have a T4S mixer and the Bose recommended power supply. I am currently powering this with a portable lithium ion battery pack (Base S360 42000 Mha) which can be solar powered. This produces a modified sine wave AC connection which appears to work OK and power the mixer for several hours. The T4S feeds a Bose S1 Pro using its internal battery pack.

The shape of the AC waveform (not being a sine wave) may affect the efficiency of the DC power supply.  This might be a factor in this observation from one of your previous posts.

David Wyatt posted: Independent power for T4S

This is what I have done. Of concern however was when plugging in the Bose power supply for the first time into the AC out of my SBase 360 portable power supply it is the first time I have had the fan in the portable power supply kick in. 

? - ? - ? - ? - ? - ? - ? - ? - 



However I have a question on whether a modified sine wave battery generator can damage the T4S or its Power supply brick?

Because this is an unsupported setup, basically, you're on your own. If you damage the T4S or the ToneMatch Power Supply,  this will not be covered under warranty.

i also find that if I use the generator on the T4S but have the S1 connected to the house mains that noise is introduced into the signal. I find that odd as surely the Bose power brick is converting the modified sine wave generated AC into 18v +/- Dc used by the T4S and it was my understanding that DC does not generate ground loop noise?

By connecting both devices to different AC sources, you have increased the total ground loop area, which will increase noise. DC current can generate noise at it dissipates through a component returning to a ground plane. You have at least three loops here:

  1. Generator -> ToneMatch Power Supply -> T4S
  2. T4S -> S1 Pro
  3. House VAC –> S1 Pro

The house VAC noise could be coupling into the T4S via loop #2. and then this is fed to the front end of the S1 Pro. By connecting the S1 Pro to the house VAC, a coupling is path is introduced for hum to couple into both of these products

Finally I wonder whether the AC to DC  conversion could be avoided by using a direct 18v DC source such guitar pedal power supplies?

Guitar pedal power supplies also convert AC to DC.  

Using any power source other than AC Line to ToneMatch Power Supply (or L1 Model 1S or L1 Model II) for the T4S is not supported or covered under warranty.



Thanks for any information pointers on these issues.

David

I am sorry we couldn't be more helpful.

ST

wyattd
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Aug 16, 2018

Re: T4S Power supply

So from the response what you are saying is that no performer can use the T4S for busking off grid without invalidating warranty? How are these purchasers informed of this position at point of purchase?

Surely the product is not that vulnerable that support has to be refused by the manufacturer. 

ST - Pro
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May 11, 2020

Re: T4S Power supply

Hi David,

We're always interested in helping our customers to use our products in innovative ways and to better their craft and performances. However, we can't warranty against damage for circumstances we can't anticipate or that we can expect will harm the products.

If you damage your product by connecting it to a power supply other than AC Mains (UK terminology) that won't be covered under warranty.

Here's a link to the warranty information for Bose Portable PA products.

Here is some more information about alternative power sources.



ST