[Arcayne]

Tube rolling is trickier than I thought, how am I supposed to know which combination of tubes are safe?

Haha, I feel you. I'm still very much a noob with the technical side of tube-related things, but learning bit by bit as I go.

To be absolutely certain that you're safe, you just have to stick to the standard supported tube families, as listed in the user manual. Using tubes that aren't supported by default through the use of adapters is not encouraged nor supported by Feliks Audio, so if anything goes wrong, the cost to repair your amp will almost certainly have to come at your own expense.

As I understood it, the Euforia can provide a maximum of 7A across all 4 tube sockets. So when experimenting outside of the "comfort zone", you have to look at the data sheets of the tubes you plan to use (example: GL KT88 datasheet) to find out how much current each tube draws, defined as Ih under the Heater specs. In this case, approx 1.6A per tube, so let's assume 1.7A to be safe. Add up the Ih of all 4 tubes (4 * 1.7 = 6.8A), and that's how much current the tubes will be drawing from the amp. This should always be less than the maximum amount your amp accepts (7A for the Euforia), otherwise you need an external power source for it to work.

So you can be relatively assured that running 4x GL KT88 isn't a problem for the amp.

P.S. Correct me if I'm wrong, I'm not an expert either.

 

[Deleeh]

6SN7 works as a driver with the other stock tube, so it surprised me that it wouldn’t work as a driver with the KT88 (again, newbie here!)

Tube rolling is trickier than I thought, how am I supposed to know which combination of tubes are safe?

edit: haha figuring out quotes.

Hello,
I wouldn't go for a direct conversion at the price of the amplifier as long as it still has a 3-year warranty.

Even though I understand that it should sound "tubey", I would have bought something else like the Quicksilver or Woo Audio, maybe the Tor audio Balanced.

In the half year I have had the Euforia I have always stuck to the original tube types.
Significant difference was that the 6AS7G like to mask.
Where as the 6080's are better and swapping the Ps vane to Lin lai Elite series was huge.
For me they are totally sufficient and sound better than a solid state amp when it comes to resolution.

Keep in mind that the Euforia needs to be burned in for the first few hours.
It would not be good if you put too much strain on it right from the start.
I only know that Feliks knows about the conversion and that the warranty does not cover it.
It is possible that they have found a way to check this.

 

[ThanatosVI]

To answer question #3; No, that won't work. 6sn7s will draw too much current.

I have a set of GL KT88s + adapters from ebay as I was curious about this roll as well. Unfortunately too much power output is lost when running quad KT88 for my Empyrean to be driven adequately. I do regularly listen at 80-85 dB SPL though, so if you're a quiet listener this might not be as much of an issue for you.

The quad KT88s pair spectacularly well with my HD580, though.

In the provided sheet, the 6SN7 draw significantly less than the KT88 though.

Did I misunderstand something or did you by any chance mix up the requirements of the 6SN7 with those of the 6080? (0.6A vs 2.5A)

2x 0.6A + 2x 1.6A = 4.4A
Or is there more to it and drawing not enough current has other pitfalls?

or is the issue the gain and everything is way too silent in that configuration?

or could it be that the tubes are driven "too hard" and have significantly reduced life expectancy in that case?

 

[connieflyer]

I have used the 6SN7 and KT88's for over a year now and find them good. I also used the KT77 as drivers and KT88's as power. Also like this combo. Using the 6BL7's as power and the stock 6SN7's as drivers. Really like this combo

 

[ThanatosVI]

I have used the 6SN7 and KT88's for over a year now and find them good. I also used the KT77 as drivers and KT88's as power. Also like this combo. Using the 6BL7's as power and the stock 6SN7's as drivers. Really like this combo

That sounds interesting, in theory it could even drive KT150

Or EL34 pre with KT88 power tubes. Damn the possibilities are endless.

I love my Octave, maybe I should get a Demo unit of the Euforia AE to compare

How hot does the Euforia get?
Can you still touch it when it has been running for a few hours?

Woo Amps get very hot. My Octave only warm so that I can still comfortably touch it even after hours of use

 

[ThanatosVI]

Does the Euforia become more neutral and transparent or warmer and more tubey when using KT88 vs stock tubes?

 

[Deleeh]

Does the Euforia become more neutral and transparent or warmer and more tubey when using KT88 vs stock tubes?

The good thing about the Euforia is that its basic tuning is neutral.
And you also have the possibility to determine the tube rolling yourself.

In the end, you decide for yourself what you miss or lack.
No one can say that tube XY is so good, if your ears don't like it.
You can only share your impressions and help others to adjust their sound preferences.
That's all you can do.

This is also a bit expensive, especially with good and rare tubes.

I found the original Feliks tuning not wrong and it shines on dynamic headphones very well, especially in the higher price range.
For planar operation, however, it was only conditionally good.
But that is also a matter of taste, I found the mid and treble range on the planar headphones quite good, only the bass was lacking.

I tried other 6AS7G tubes, but they weren't my cup of tea, then I tried the 6080 tubes, which were better, but the final touch was still missing.
That only came with the exchange of the Ps vane against other 6SN7 tubes.
This process happened step by step and took time.
And somewhere you reach your limits, it has to be said.
You can't have everything and you have to make compromises, but if the main criteria are met, that's worth a lot.

Of course, the dac also plays a role and possibly the software dinman uses such as Audirvana 3.5 or Studio or Roon.
All of these things play together, not just the tube itself.

Therefore give the Euforia time after unpacking, pay attention to the burn in time, give the tubes time to burn in.
The enamel comes on its own when it is there and they are then also ripe.

Keep in mind the Euforia I find to be a sensitive charming polish girl who just needs enough love and is often satisfied with less than she needs to play up properly.
I love to hear the pairing with the Lcd 2C when the 6SN7 tubes from Lin Lai and the 6080 Mullards or Sylvania are fitted.
The nice rich bass, fabulous mids and highs that are very warm and full bodied.
And very musical tube pairings that always get under your skin.

 

[ThanatosVI]

The good thing about the Euforia is that its basic tuning is neutral.
And you also have the possibility to determine the tube rolling yourself.

In the end, you decide for yourself what you miss or lack.
No one can say that tube XY is so good, if your ears don't like it.
You can only share your impressions and help others to adjust their sound preferences.
That's all you can do.

This is also a bit expensive, especially with good and rare tubes.

I found the original Feliks tuning not wrong and it shines on dynamic headphones very well, especially in the higher price range.
For planar operation, however, it was only conditionally good.
But that is also a matter of taste, I found the mid and treble range on the planar headphones quite good, only the bass was lacking.

I tried other 6AS7G tubes, but they weren't my cup of tea, then I tried the 6080 tubes, which were better, but the final touch was still missing.
That only came with the exchange of the Ps vane against other 6SN7 tubes.
This process happened step by step and took time.
And somewhere you reach your limits, it has to be said.
You can't have everything and you have to make compromises, but if the main criteria are met, that's worth a lot.

Of course, the dac also plays a role and possibly the software dinman uses such as Audirvana 3.5 or Studio or Roon.
All of these things play together, not just the tube itself.

Therefore give the Euforia time after unpacking, pay attention to the burn in time, give the tubes time to burn in.
The enamel comes on its own when it is there and they are then also ripe.

Keep in mind the Euforia I find to be a sensitive charming polish girl who just needs enough love and is often satisfied with less than she needs to play up properly.
I love to hear the pairing with the Lcd 2C when the 6SN7 tubes from Lin Lai and the 6080 Mullards or Sylvania are fitted.
The nice rich bass, fabulous mids and highs that are very warm and full bodied.
And very musical tube pairings that always get under your skin.

So with the Stock tubes the Euforia is rather lean in the Bass, but with some Rolling you can get solid State like oomph back?

I really like KT88 sound and had several amps with those.
However they mostly rund 12au7 which are said to sound worse tha 6SN7.
With this new knowledge that the Euforia can potentially run both, I'm intrigued to try it.

My headphones are all easy to drive, which makes the limited Power output less of an issue

 

[mordy]

The good thing about the Euforia is that its basic tuning is neutral.
And you also have the possibility to determine the tube rolling yourself.

In the end, you decide for yourself what you miss or lack.
No one can say that tube XY is so good, if your ears don't like it.
You can only share your impressions and help others to adjust their sound preferences.
That's all you can do.

This is also a bit expensive, especially with good and rare tubes.

I found the original Feliks tuning not wrong and it shines on dynamic headphones very well, especially in the higher price range.
For planar operation, however, it was only conditionally good.
But that is also a matter of taste, I found the mid and treble range on the planar headphones quite good, only the bass was lacking.

I tried other 6AS7G tubes, but they weren't my cup of tea, then I tried the 6080 tubes, which were better, but the final touch was still missing.
That only came with the exchange of the Ps vane against other 6SN7 tubes.
This process happened step by step and took time.
And somewhere you reach your limits, it has to be said.
You can't have everything and you have to make compromises, but if the main criteria are met, that's worth a lot.

Of course, the dac also plays a role and possibly the software dinman uses such as Audirvana 3.5 or Studio or Roon.
All of these things play together, not just the tube itself.

Therefore give the Euforia time after unpacking, pay attention to the burn in time, give the tubes time to burn in.
The enamel comes on its own when it is there and they are then also ripe.

Keep in mind the Euforia I find to be a sensitive charming polish girl who just needs enough love and is often satisfied with less than she needs to play up properly.
I love to hear the pairing with the Lcd 2C when the 6SN7 tubes from Lin Lai and the 6080 Mullards or Sylvania are fitted.
The nice rich bass, fabulous mids and highs that are very warm and full bodied.
And very musical tube pairings that always get under your skin.

Thanks for your vivid and nice description of how it sounds!
Only want to add that the amp needs upwards of 150 hours of burn-in to sound it's best. That refers to the amp itself - then the individual tubes also need their time; 30-50 hours is a good rule, but some older tubes may need more or much more.

 

[Arcayne]

In the provided sheet, the 6SN7 draw significantly less than the KT88 though.

Did I misunderstand something or did you by any chance mix up the requirements of the 6SN7 with those of the 6080? (0.6A vs 2.5A)



2x 0.6A + 2x 1.6A = 4.4A
Or is there more to it and drawing not enough current has other pitfalls?

or is the issue the gain and everything is way too silent in that configuration?

or could it be that the tubes are driven "too hard" and have significantly reduced life expectancy in that case?

You're right! I was mixed up between 6sn7 and 6080... My apologies!

 

[Sunset1982]

I had an euforia ae for loan this weekend. The bass was totaly overblown on my empyreans with bifrost 2 as a dac. same with topping e30. used pc, ipad and rpi streamer as a source. the rest of the sound spectrum was nice, bit the bass crackled like a broken speaker. any idea what the problem could be?

 

[Deleeh]

So with the Stock tubes the Euforia is rather lean in the Bass, but with some Rolling you can get solid State like oomph back?

I really like KT88 sound and had several amps with those.
However they mostly rund 12au7 which are said to sound worse tha 6SN7.
With this new knowledge that the Euforia can potentially run both, I'm intrigued to try it.

My headphones are all easy to drive, which makes the limited Power output less of an issue

My statement tended to refer to planar headphones and not to dynamic headphones as far as bass is concerned.
With dynamic headphones, everything is good and completely sufficient.

At least that was my impression.
And also obviously when you come down from solid state with the Lcd 2C you know what it can do.
It felt a bit bloodless, but you can get used to it, it's less fun and more unagitated.

On the Fostex Tr x00, on the other hand, it's a blast and no comparison.
So it's really fun.

@Sunset1982

Good question, did the cabling fit? Usb and Rca cable?
It's probably not normal.
How did you connect it to the pc, notebook ? Power strip ok ?
Otherwise, try reducing the overall volume on the PC/notebook from 100 to 90, maybe it's a slight clipping.
The driver may also be from the PC/notebook.

Have you changed the internal audio sampling of the PC?
There you can set how it should sample.
At the bottom right of the bar, right-click on the speaker and press Open Sound Settings.
When the window opens, click on Sound Control Panel on the right and select Bitfrost or E30 and click Properties.
In the new window in the grid, look for Advanced and then you can change the sampling mode and then save.

 

[Arcayne]

I had an euforia ae for loan this weekend. The bass was totaly overblown on my empyreans with bifrost 2 as a dac. same with topping e30. used pc, ipad and rpi streamer as a source. the rest of the sound spectrum was nice, bit the bass crackled like a broken speaker. any idea what the problem could be?

How loud are you listening, what's the position of the volume knob?

 

[LoryWiv]

To answer question #3; No, that won't work. 6sn7s will draw too much current.

I have a set of GL KT88s + adapters from ebay as I was curious about this roll as well. Unfortunately too much power output is lost when running quad KT88 for my Empyrean to be driven adequately. I do regularly listen at 80-85 dB SPL though, so if you're a quiet listener this might not be as much of an issue for you.

The quad KT88s pair spectacularly well with my HD580, though.

Respectfully, that is incorrect.

• KT-88's draw 1.6A = 3.2A / pair.
• 6SN7's draw 0.6A = 1.2A / pair
• Total of 4.4A is well within Euforia's heater current handling

I have run various 6SN7's driving KT-88 many times with no adverse effects and often the result is excellent sound. As they say, YMMV.

 

[Arcayne]

Respectfully, that is incorrect.

Indeed, I was made aware of that earlier. Edited the post.