FX Audio 6j1 tube preamp - a $31 wonder

I'd like to know if anyone is reversing polarity of their FX? That is swapping positive for negative speaker wires on both amp channels. I think I'm hearing a more dynamic sound but can't tell for sure if it's not playing tricks on my ears? I need other's opinions on this.

I have not tried it with the FX as i'm currently waiting for the seller to get back to me. Its all packed away.
I did however try reversing the speaker cables in my main setup. The swap was brief but to my surprise there was a difference.
 
I've not heard the setup in my main rig, but i've ordered some different tubes (5654w) to try.
Hopefully i get a replacement unit asap.

I'm officially infected
With this sorta thing...The next tube pre / internet sensation might just be around the corner. :D

I'm hoping that i'll be incredibly happy with my system by then ... and that it wont bother me.
 
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Here is a cool link that grades most of the EF95 family tubes available for the FX. This was written for the Little Dot amp but it uses the same tubes for the front end.

https://www.head-fi.org/threads/little-dot-tube-amps-vacuum-tube-rolling-guide.563884/

I would like to try those Tung-Sol 6AK5 tubes.

Thanks for that post. It pretty much sums up my experience with the stock tubes. They are definitely a little muddy in the bass department.

I'd like to know if anyone is reversing polarity of their FX? That is swapping positive for negative speaker wires on both amp channels. I think I'm hearing a more dynamic sound but can't tell for sure if it's not playing tricks on my ears? I need other's opinions on this.

I'm running mine "reversed", that is to say the speaker wires are pos to neg and neg to pos (amp to speaker). The sound is definitely more dynamic and the soundstage is more in front or focused. As for being leaner, it's just the opposite for me. :dunno:
 
I've read a few articles and posts on reverse polarity and some claim there's little to no audible difference while others can clearly hear a difference. Some preamps even have a button to reverse polarity which makes sense as some recordings are recorded using reversed polarity. When I reversed polarity with the FX ( since it supposedly is already reversed ) the sound was more lively and dynamic but thinner sounding. Now I've switched back and the sound is fuller but less dynamic. With full range single drivers ( time aligned ) I may be getting a different effect compared to multi driver speakers.

Update; I'm pretty sure I prefer the FX with conventional speaker polarity but it is interesting and fun to try it both ways.

It is a controversial topic. I was on a jazz forum where a prominent member was convinced of the benefits of reversing polarity. Until it was discovered he had his cables reversed, either at the speaker connection or to the amp. There is that factor of human error that contributes to this.
 
Reversed I'm getting more dynamics, a livelier in-your-face presentation but less cohesive and the sound stage seems slightly hyped and unnatural.

Is it a bit of a reverb effect we're hearing that sounds good in the short run but not over the long haul? Wish I could switch back and forth as audio memory is short and

not so trustworthy.
 
I'd like to know if anyone is reversing polarity of their FX? That is swapping positive for negative speaker wires on both amp channels. I think I'm hearing a more dynamic sound but can't tell for sure if it's not playing tricks on my ears? I need other's opinions on this.
I can tell you this is real without doing it with the same item, I had the same experience with a Conrad Johnson pre that inverts polarity. Some recordings may have inverted polarity and will sound better with the reversal. Other content may not give an obvious difference, but setting up for the majority of content makes sense.
 
This little preamp is pretty versatile. I have a guitar headphone amp that I practice with from time to time. I know the FX is a buffer too, so I just tried outputting the guitar headphone amp to the FX and playing through the stereo. Damned if it doesn't work really well and sound good. The headphone amp has an input for my phone, so I can play along with the music. Fun stuff!
 
Well i gave in and reversed the polarity.....then changed back.Im more than happy with things.
FX also works well with monstrous Technics amp from days of yore....
Might just get another FX before the price goes up.:)
 
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Reversed I'm getting more dynamics, a livelier in-your-face presentation but less cohesive and the sound stage seems slightly hyped and unnatural.

Is it a bit of a reverb effect we're hearing that sounds good in the short run but not over the long haul? Wish I could switch back and forth as audio memory is short and

not so trustworthy.

Hey Poultry. A couple of questions. You know your tubes. Would this work in the FX? And even if it doesn't is this is a good tube?

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You need tubes from the same "family" to consider tube swapping, and circuits may be optimized for a particular type.
"Different" is easy, "better" not so much.
 
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