# Cypher Labs Theorem 720

Discussion in 'Portable Headphone Amps' started by drsheep, Sep 3, 2013.

1. Does anyone have the 13's? I was wondering how it paired with them and if there was any hiss. Also is there any benefit in going balanced with the 13 or 16 fp's?

2. Contributor
It has everything to do with how sensitive you are and your gear is to hiss. Some people aren't bothered by it. That said, the JH13Pro are less sensitive than a lot of earphones. I hear hiss from them with a number of sources but they are very good at suppressing the worst of it from every amp.

3. I decided to go for it and ordered a theorem today from TTVJ.  Very much looking forward to it.  How does the dac compare to the clas db?

4.
Small/Acceptable hiss with 16's using single end.

5.
looking forward to your impressions =)

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6.
It's the same DAC as the db and R, it's different from the original solo

7. Thanks, I knew it was the same dac I was wondering how the theorem dac sq compared to the db. I may be wrong but I thought that the implementations were different.

8. Contributor
They are both top notch in their fields. Theorem relies on another output source, so the two (as independent units) can perform differently. I've found the Theorem's output to outperform most amps out there, so it is truly mated to a great output. You'd have to spend a lot more on an analogue output system for the dB to reach the same level.

9. Thanks. Does the dac in the theorem get power from the internal battery and not externally from usb?

10. Correct, it's not USB powered

11. The 720 hissed with the JH 13 pro's for me. See my review earlier in this thread.

12. Contributor
It's not a for your or for her thing: every source hisses. It is outed by sensitive output devices. Some people are not bothered by it. Amazingly, some people get on with the likes of the AMP3Pro. The Theorem is of course a lot less hissy but as you said, it makes noise. Fortunately it is neutral noise and totally liveable.

13.
Shigzeo,
What do you mean by neutral noise?  Thanks.

14. The hiss was not from the source but from the Theorem 720 as I verified by trying the exact same setup on another amp without any hiss. I was bothered by the hiss.The hiss was neither neutral nor livable for me. Which is why I sent the 720 back.

15. Contributor
I'm sorry, I was vague. I meant that the noise has no peaks or troughs; as long as your batteries are charged, it is a constant volume that doesn't change on cable wiggles or the volume of the music played from the source. It is exactly the sort of noise that you want- if you have to have it. My Walkmans and AMP3Pro not to mention one or two other amps, have noise that modulates even when you are not touching the chassis or twiddling the volume pot. Those non-neutral noise signatures are annoying.