Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: Can I purchase a 4.5V DC adaptor and use in the transmitter instead of batteries?
Document: You can use batteries but as the battery weakens, so will the power output. You can use any 4.5 V DC adapter (with the right polarity and tip). The polarity is marked behind the transmitter. GET IT RIGHT or your Tx wont work.
I use aSANYO 4-Position Ni-MH Rechargeable Battery Chargerto recharge all four batteries, and it takes about eight hours.We don't have a cable box, so the base is plugged into the back of the TV. We do have another set for the TV in the bedroom, and that one needs to be plugged into the Roku box. If you have a Roku box and the headphones don't work when you plug the base into the TV, try that instead.
Not bad quality for the price, does what i need it to and i like how the antenna has the option to use a 4.5v power adapter instead of batteries (power adapter was not included).
I'm only giving it 4 stars because the headphones are so bulky so I get a bit tired of my head sitting up, and you must remember to turn both the headphones and the transmitter OFF or the batteries will need to be replaced next time you go to use them. But they do work, really well. Don't think they will work if you're trying to use them and clean or walk around, you need a direct line of sight to the TV.
Very clear audio. Just turn the power on (on the head phones) and hit scan once.I use these in bed after my wife goes to sleep. 4 stars is becuase I was disappointed it did not come with a power adaptor to plug in the receiver so I purchased thisSony AC-E45A Worldwide AC Power Adaptor with Folding Plug Bladeand it worked great. Now I don't have to get up out of bed and turn on the reciver every time I want to use the head phones.
This product does what I need it to do. If I had one wish I would make the transmitter have a plug instead of batteries. That would have made it 5 star.
I bought these for $10. I expected them to barely work. I hooked them up with two rechargable AA batteries in the transmitter, and could barely hear anything other than static farther away than 3ft.I removed the fake empty plastic pieces of the transmitter, and soldered the + and - leads of a USB cable to the DC input leads of the power plug. I am writing this the same night, though the capacitors and components are not getting hot or warm.
Bought this to replace the tv ears that I had, which never lived up to expectations or claims and got ridiculously expensive to replace. These are a little more cumbersome and uncomfortable than the tv ears, and use batteries, but, for the difference in price, it was worth the risk. They have worked well so far, except that every once in a while, I get extra static. Should have come with the plug in adapter instead of having to order that separately.
These headphones work great and gives my hard of hearing Mother a chance to hear all the dialogue. What is great also is that we can turn off the volume in the room and not be disturbed while she listens to her programs. What a blessing! The only drawback is that is does not come with  an AC adapter for the transmitter and the AA batteries must be changed frequently. I bought an  4.5 v adapter online but it doesn't interface with it,  so I'm still looking for one.
The range is supposed to be 30 feet or so I think. That's true for about an hour, then the batteries in the base are not strong enough anymore. You can and I did use a 4.5 VDC power brick to eliminate that problem.
Answer: Yea you can. I am using one for saving and convenience.