FX Audio 6j1 tube preamp - a $31 wonder

I use an ifi ipower which is excellent, a mean well switching that is not bad (the one that Uptone audio bundles with the regen) and I have a very nice Keces linear power supply that i will try this weekend. the one that comes with the Rpi is not so good.
 
If that is a picture of the DAC you have, then it is a Piano, rather than a Boss.

If you do have the Piano 2.1, the best results are achieved by running it in ''dual mono' mode, with the interconnects using the two outermost RCAs. If the software you use supports it, can I suggest trying again in this mode?

People who do use the Piano improve things further using a Kali board to reduce jitter, and even further by using an Isolator between the RPi and the DAC.

Of course, after all of this you still have ESS Sabre chips, which people seem to love or hate...
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thank you for the suggestions. i am hearing some good things now. a number of very positive changes occured with changing some settings

that dual mono thing did help but a huge improvment came from turning on the i2s DAc setting and then setting the output device to allo piano

im gonna let it play some pop radio station for 48 hours and then go back to it, but it already sounds better. i might have to retract that garbage comment. it still sounds very lacking in microdynamics but it doesnt sound that sibilant. i might actually consider than reclocker now. i will have to also go back to the tubes and reevaluate them. my previous comments was after 24 hours burn in, now im gonna give it two more days.
 
So I raided that spare change jar and purchased the FX TUBE-03 with tone control.

20190212_124826.jpg

This unit will eventually go into my little art studio for late night company while I doodle. But in the mean time I got antsy and needed to settle my curiosity if this unit even works. I'll start out by saying the unit was well packaged for shipping. Instruction manual was pretty light but I could figure it out. Been snowing off/on here the past week, traffic sux and my ext. pwr supply is at my other house now so wall wart had to do, however I did have some GE JAN 5854W tubes already burned in so didn't bother with stock tubes. The unit was initially connected between my oppo BDP and ARC SP-15 pre, then on to ARC vm-220 monoblocks and out to Maggie 1.6s, it was allowed to warm up for a 1/2 hour before any "listening" took place. 1st up was a SACD copy of Norah Jones as I know this one well on my system. Other music was played but not worth mentioning here.
With tone controls centered and volume level set accordingly my first impression was a bit lack luster. Highs were somewhat muffled and no sparkle to speak of, mids were present and tonality was acceptable but perceived a bit forward and constricted in space, bass was a tad flabby in sound and lacking in deep richness in addition to that very centered between the panels with hardly any overlap or spread beyond the panels, very little openess or air about the sound. I made some adjustments to the tone controls (bass down a detent or 2 and treble up a couple 3 detents) and it sounded some better but didn't bowl me over.
Light bulb went off and I remembered I have a pair of burned in 1945 Sylvania JAN-6AK5 tubes in a buffer on one of my other systems. Did the swap, gave it time to warm, poured one and sat down for a "listen".
Starting out with controls flat I immediately noticed an over all tone quality improvement including some amount of increase in air/space around the instruments and a bit closer to that sparkle I was looking for, that "tang" sound of a drumstick tip hitting a cymbal or the proper sound of a high hat and not 2 trash can lids being smacked together. I continued to notice some lack in spatial information and environmental detail of the music but better than the GE tubes, in addition the midrange still sounded a bit over centralized or compartmentalize if you will. Although the bass tightened up exponentially and was much fuller plus more natural sounding I was still not hearing that fundamental stuff I normally hear and enjoy. It's as if 30Hz was the limit and then began roll off with nothing below 25Hz. Published specs are 20-20kHz +/- 1.5.
So, with the 1945 tubes and little tone control nudging I was able to achieve a somewhat satisfying sound out of this little unit, but once I took it out of the loop I could instantly hear it's limitations as everything I was familiar with on this recording returned. I thought maybe it didn't play well with the oppo so I put it line between my streamer w/quad dac and SP-15 thinking it might "warm up" the sound a bit. It did but the previously identified artifacts were there once again.

In conclusion:
I never expected this little $52 item to compare in sound to a $30,000 system as that wasn't the point here. However by connecting it into a system of that quality any shortcomings would become abundantly obvious and allow me the ability to identify these things, so going forward my expectations of this unit can be much more accurate. The FX TUBE-03 will never reside with my ARC system as that is not what I bought it for. Once a better quality power supply is aquired I will be more than happy with the performance of this little unit where I plan to use it in my world. Of course YMMV but between initial cost, tube upgrade and a better power supply, it's a worthy little unit in my opinion and I'll be keeping mine.
Eventually it will be part of a system of stuff left over or displaced to include dbx 1bx-ds, dbx 120x (for sub control), Carver m400 cube, ADS speaks and a small 12" infinity sub w/plate amp.

Hope this writing helps someone here.
 
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thank you for the suggestions. i am hearing some good things now. a number of very positive changes occured with changing some settings

that dual mono thing did help but a huge improvment came from turning on the i2s DAc setting and then setting the output device to allo piano

im gonna let it play some pop radio station for 48 hours and then go back to it, but it already sounds better. i might have to retract that garbage comment. it still sounds very lacking in microdynamics but it doesnt sound that sibilant. i might actually consider than reclocker now. i will have to also go back to the tubes and reevaluate them. my previous comments was after 24 hours burn in, now im gonna give it two more days.

And possibly buy one of IanCanadas DAC's on diyaudio?

You may also want to try PiCorePlayer or Moode; both seem to get a better SQ from the Piano DAC than Volumio, according to a lot of user reports I've seen. I use PiCorePlayer, which is extremely configurable, and sounds the 'best' to me, with my equipment.
 
And possibly buy one of IanCanadas DAC's on diyaudio?

You may also want to try PiCorePlayer or Moode; both seem to get a better SQ from the Piano DAC than Volumio, according to a lot of user reports I've seen. I use PiCorePlayer, which is extremely configurable, and sounds the 'best' to me, with my equipment.
i have heard a lot of praise for ians products. this does look good. it might persuade me to give 9038 a try:
https://farm8.staticflickr.com/7891/32136607127_a552e34791_o.jpg
32136607127_a552e34791_o.jpg


on the other hand khadas would be cheaper and ready to use and not dependent on rpi. have you have expereuce with the khadas tobeboard? it is a stand alone dac and usb bus powered.

edit: gotts say his ordering process is atrocious.he didnt even update the 1st post . i cant even find the post that has the details and prices because the thread is 300 pages long :|
 
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i have heard a lot of praise for ians products. this does look good. it might persuade me to give 9038 a try:
https://farm8.staticflickr.com/7891/32136607127_a552e34791_o.jpg
32136607127_a552e34791_o.jpg


on the other hand khadas would be cheaper and ready to use and not dependent on rpi. have you have expereuce with the khadas tobeboard? it is a stand alone dac and usb bus powered.


Yes, I have a KTB, the generic version. I've tried it with a USB connection to a PC, an RPi, and an android phone. Being very impressed, initially, I now have it connected via SPDIF (thus able to use the USB C port for a linear PSU only) to an IQAudio Digi+ on an RPi, feeding an IcePower 50ASX2 amp via an ne5534 buffer. It sounds very good.

I am also in the GB for IanCanadas stuff, almost as per the picture you posted...
 
Yes, I have a KTB, the generic version. I've tried it with a USB connection to a PC, an RPi, and an android phone. Being very impressed, initially, I now have it connected via SPDIF (thus able to use the USB C port for a linear PSU only) to an IQAudio Digi+ on an RPi, feeding an IcePower 50ASX2 amp via an ne5534 buffer. It sounds very good.

I am also in the GB for IanCanadas stuff, almost as per the picture you posted...
i will probably go with the KTB but could you let me know how much this configuration adds up to price wise? i still cant find the post in which he lists the new GB prices. im sure this info will be useful to many. as these rpi based stresmers + daca are very versatile and offer great value.
 
i will probably go with the KTB but could you let me know how much this configuration adds up to price wise? i still cant find the post in which he lists the new GB prices. im sure this info will be useful to many. as these rpi based stresmers + daca are very versatile and offer great value.

Ian hasn't finalised the prices yet, but these are the latest estimates, which I don't expect to be too different:

https://www.diyaudio.com/forums/gro...us-i2s-pdif-fifo-kit-buy-293.html#post5694742
 
Just a heads up. My new fx01 just failed spactacularly. A series of loud pops from the right channel and then that side went out. Fortunately all other components are fine. The adcom power amp, m7s and all sources work top flight. The tc-754 directly into the adcom sounds excellent so i am going to count myself lucky and listen without a buffer.
 
Just a heads up. My new fx01 just failed spactacularly. A series of loud pops from the right channel and then that side went out. Fortunately all other components are fine. The adcom power amp, m7s and all sources work top flight. The tc-754 directly into the adcom sounds excellent so i am going to count myself lucky and listen without a buffer.
Youre not gonna do some trouble shooting? It is probably the tube failing. It happens, tubes fail a lot.
 
Youre not gonna do some trouble shooting? It is probably the tube failing. It happens, tubes fail a lot.
i will troubleshoot it. as for tubes failing regularly, ive had the same tubes in my vox nightrain that i use 3-4 times a week for 4 years. no failures yet. this is unacceptable performance. the vox works its tubes significantly harder. ditto for almost every other piece of tube gear i have owned.
 
i will troubleshoot it. as for tubes failing regularly, ive had the same tubes in my vox nightrain that i use 3-4 times a week for 4 years. no failures yet. this is unacceptable performance. the vox works its tubes significantly harder. ditto for almost every other piece of tube gear i have owned.

I have had similar things happen to me with tubes. You may have just gotten a bad tube. It may not be the preamp.

Good luck and let us know!
 
The FX is handling more sources thanks to the five input Niles switch box ( just below the drawer ). It allows switching between a Sony SACD changer, a Rotel CDP, Sansui tuner, and Topping D30 DAC. The DAC is connected to a PC via usb, a Chrome Cast Audio streamer via optical and the Rotel via coax. I've labeled everything otherwise I'd never keep it all straight.

Still going with the FX driven APPJ/Miniwatt SET amp. It's case is it's heatsink so it loves these cooler temps. The Volt+D is now driving some Eminence woofers in the Lowther OB system. Changing things around is half the fun.

P1010004.jpg
 
Son is dropping off his Pyramid PS14KX (13.8v 12a) power supply today around noon -- will give it a try

Also , no disrespect to Pio , I'm going to try powering both the FX and Volt+D with ^ that P/S and see how they sound


Did you try it?


Yes... I dont have that many hrs on the FX -- Mullard tubes are good to go

But being what it is... the Pyramid PS14KX (13.8v 12a) drove both really well. Am almost positive the Pyramid PS14KX is better than the switching P/S that came with the FX

Jury still out on the Volt+D -- I like the SQ using a 19v wall wart with it

I need more time
 
The FX is handling more sources thanks to the five input Niles switch box ( just below the drawer ). It allows switching between a Sony SACD changer, a Rotel CDP, Sansui tuner, and Topping D30 DAC. The DAC is connected to a PC via usb, a Chrome Cast Audio streamer via optical and the Rotel via coax. I've labeled everything otherwise I'd never keep it all straight.

Still going with the FX driven APPJ/Miniwatt SET amp. It's case is it's heatsink so it loves these cooler temps. The Volt+D is now driving some Eminence woofers in the Lowther OB system. Changing things around is half the fun.

View attachment 1419220

Wow! amazing system! How does it sound compared to the Volt+D?
 
Wow! amazing system! How does it sound compared to the Volt+D?

Thanks. Absolutely love them both and can not decide which I prefer. The APPJ/MW has a new lease on life thanks to the added gain of the FX. I'm sure I'll be rotating each one in and out of the system. I once had an expensive Classe amp that didn't have the resolution these two offer.
 
Thank you PG for bringing up this preamp. Here you go again making me spend the big bucks. Got it yesterday and tried it on my main system with the stock tubes and stock power supply. My main system consists of Magneplanar 1.7's powered by a Conrad Johnson MF 2300A or a Jolida 502 P power amp. Preamp is a Mapletree 2ASE, uses 6SN7 and was designed and built by a retired EE professor in Canada and sells for many multiples of the cost of the FX Audio preamp.
Well, the sound with the stock FX was amazing even just out of the box, good imaging, good bass, no odd noises, adequate gain. It's a bit brighter than the Mapletree and a bit edgier, plan is to let it cook for a few days and see if the stock tubes mellow out, if not I'll try the GE's. Also was wondering if the PS for a Lepai amp (12 V 2 amps) would work for this preamp and be an improvement?
 
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