Feliks Audio Echo (new budget OTL amp)

[Nuhapaatti]

Since I read from this thread that some people have had good results with some 12au7 tubes /w adapters, I decided to test it out myself too. Results weren't that good I had read. I have had Tubemonger 12xx7 to 6922 adapters but also some chinese ones, both adapters give this radio frequency like oscillation with JJ ECC802s & JAN GE 5814a's (both equivalents to 12au7 since I thought that would give least gain bump to particularly avoid any oscillation problems).

Would love to hear from others that have used adapters with Feliks Audio Echo 2 with good or bad results and maybe some kind of explanation why would this happen (other than the amplifier wasn't made for them since some have had good times with adapters but I don't)? I know that too much gain, negative feedback or so on might result in this kind of behaviour but since other users haven't had to deal with this kind of behaviour, is there something in the amp that I should be considered?

I did only test those out but when I heard the noise, I immediatly changed back to the tubes that are made for this amplifier.

 

[Nuhapaatti]

This is unholy and sad but I have to make a double post. I was a little compromised buying these (I promise, these are the last pair since I took them in as an little investment) tubes but local very reputable dude sold me these dirty cheap (compared to their market price of course, that would be). I've never had this valuable genuine NOS item (I'd guess, there's plenty but now I could start to get rid of them). So let me introduce you the highest I'll ever go buying tubes since I can't but laugh at the CCa prices, Siemens E188CC NOS tubes. They're warming up at the moment (they were very stiff to stick in so the pin diameter must be thicker) so I'll let you know how these compare to some cheaper options out there and of course compared to the OG tubes that come with the amplifier; this'll take some time just to have everyone interested to be pleased since I guess the review wouldn't be too reliable if I'd just listen a gew songs today through these (don't know yet why) pretty pricey tubes (in my humble opinion)!

EDIT: Okay, they are good, so holographic it made me dizzy. But are they worth it...

 

[Digital Enigma]

Ive really come around on the looks of the new echo its really grown on me, so much that im going to order one very soon.

Im going to start with stock 6N1P, Philips ECC88 NOS and some JJ Gold ECC88 (I don't shun new production tubes)

 

[Nuhapaatti]

I have the JJ E88CC's for the Echo 2 too and they are very nice tubes! I think they're pretty transparent with nice thump in the upper lows. If the tube is working and sounds good, doesn't matter if it is old or new, hehe!

 

[Digital Enigma]

This is unholy and sad but I have to make a double post. I was a little compromised buying these (I promise, these are the last pair since I took them in as an little investment) tubes but local very reputable dude sold me these dirty cheap (compared to their market price of course, that would be). I've never had this valuable genuine NOS item (I'd guess, there's plenty but now I could start to get rid of them). So let me introduce you the highest I'll ever go buying tubes since I can't but laugh at the CCa prices, Siemens E188CC NOS tubes. They're warming up at the moment (they were very stiff to stick in so the pin diameter must be thicker) so I'll let you know how these compare to some cheaper options out there and of course compared to the OG tubes that come with the amplifier; this'll take some time just to have everyone interested to be pleased since I guess the review wouldn't be too reliable if I'd just listen a gew songs today through these (don't know yet why) pretty pricey tubes (in my humble opinion)!

EDIT: Okay, they are good, so holographic it made me dizzy. But are they worth it...

Where did you order these from?

 

[Nuhapaatti]

Local electric parts retailer (instrument / amplifying electronics) had bought somewhere around ~25 pieces of them in original boxes completely unused. I got the pair for 140e (before buying them, I compared the asking price to the prices of other retailers and they were pretty cheap I'd say, I always compare the price to the completed purchases and not what people are asking for them). So eventually I was like why not, they're from the same date, same Siemens & Halske factory, same codes inside the tube, both 100% and great tubes must say, not even near the asking price (no pair really is worth 140e if you ask me without this tube craze) if we forget the markets but they're what they are, good tubes what so ever). And because of the markets are like they are and my own bank is what it is, I'm thinking about investing for the rest of them probably.

 

[Nuhapaatti]

I don't know how this could be done since human being's audio memory is so poorly engineered, I don't even remember how my other tubes 'sound' but here we go. So, I paid less than the market price easily for these and they are the best tubes (I think) I have ever put into the amplifier.

Might also be psychoacoustics related situation of me saying to myself that that was it, no more rolling on any prices even buying to sell in some point. That releases human being of that 'doubt' that there might be something even marginally better than the tubes in the amplifier and makes the same creature to focus to the music yet again, not the machinery working to produce it; this might play for the team of these Siemens E188CCs.

Long story short, trying to be the human I am and defy all the documents proving how stupid we really are, I try to describe this tube. It gave the already great amplifier and it's predeseccor Tesla E88CC more clarity and space. You really are in the studio and I found myself drifting many times to great the great Scandinavian rock classics. It's so easy pick different instruments and I did actually find some audio from so familiar songs to me that I was kinda baffled that now I realize there was that, not particularly a work of art by Siemens (while being so) but also could be me coming back from listening equipment back to the earth. Yeah, someone described these as the best parts of CCa's & Amperex 7308's combined as one, while not ever heard neither of those and probably will not, I can say that the people who have described those tubes, this might be very much true. For 70e a piece, I think it's just on the line (for me) for paying pretty much for any kind of tube. Market price, me, and few other things still weighed more on the scale and I'm pretty happy they did so. I don't think I'm at least yet selling these forward, other tubes I will be selling from PCC88 to E88CC and from 6922 to ECC802s. It's great tube and if you can get a pair for this 'cheap' price of 140e pair, it's a upgrade IMO even though this amplifier doesn't really need to be upgraded; these tubes just add more space, clarity (not harsh at all), smooth highs and lows that both are extended bringing you to the place of action, in front of the possible vocalist in the middle that is so delicate.

I would be interested if anyone have ever did any kind of cap swapping for this beast since mine has been in use for some time since being a demo from local hifi store. Any photos of inside or any recommendations for the caps to be swapped in are more than welcome!

 

[Honeypot]

Updated version of the Feliks Audio Echo, now called Echo Vibe.

New wooden panels, new trafo cover for better shielding
Optimized internals (upgraded capacitors).

And power supply...

Since I read from this thread that some people have had good results with some 12au7 tubes /w adapters, I decided to test it out myself too. Results weren't that good I had read. I have had Tubemonger 12xx7 to 6922 adapters but also some chinese ones, both adapters give this radio frequency like oscillation with JJ ECC802s & JAN GE 5814a's (both equivalents to 12au7 since I thought that would give least gain bump to particularly avoid any oscillation problems).

Would love to hear from others that have used adapters with Feliks Audio Echo 2 with good or bad results and maybe some kind of explanation why would this happen (other than the amplifier wasn't made for them since some have had good times with adapters but I don't)? I know that too much gain, negative feedback or so on might result in this kind of behaviour but since other users haven't had to deal with this kind of behaviour, is there something in the amp that I should be considered?

I did only test those out but when I heard the noise, I immediatly changed back to the tubes that are made for this amplifier.

I have the tubemonger 12axx7 to 6922, some Chinese ones from AliExpress, and other from a friend in Vietnam who makes them himself. All of them worked just fine with no difference in operation or sound. Only the Chinese ones get hotter, I don't know if it's because the outer side it's copper and thus more heat transfer or they have thinner interconnects and get hotter. In anyway, never had an issue with them or with the 5814 to 6922.
Remember the echo will not provide enough juice to power 12au7 properly. 6922 and 5814 will always work better.

This is unholy and sad but I have to make a double post. I was a little compromised buying these (I promise, these are the last pair since I took them in as an little investment) tubes but local very reputable dude sold me these dirty cheap (compared to their market price of course, that would be). I've never had this valuable genuine NOS item (I'd guess, there's plenty but now I could start to get rid of them). So let me introduce you the highest I'll ever go buying tubes since I can't but laugh at the CCa prices, Siemens E188CC NOS tubes. They're warming up at the moment (they were very stiff to stick in so the pin diameter must be thicker) so I'll let you know how these compare to some cheaper options out there and of course compared to the OG tubes that come with the amplifier; this'll take some time just to have everyone interested to be pleased since I guess the review wouldn't be too reliable if I'd just listen a gew songs today through these (don't know yet why) pretty pricey tubes (in my humble opinion)!

EDIT: Okay, they are good, so holographic it made me dizzy. But are they worth it...

Nice tubes, I have a pair, but they are a bit thin to my sound preferences.

 

[Nuhapaatti]

Thanks for the info about 12au7! 5814 was oscillating too though (which I guess is equivalent more or less), I think that I get my Feliks checked by a professional for spring time check up, hehe! (It probably has been used a lot since I asked the sales date to the Hifi store that's demo it was from the Feliks Audio themselves so it's not in vain I'd think)

EDIT: Yeah, those tubes are great. They play great in symbiosis with ATH-R70x which is a little warmer side of fully neutral sound I'd say.

 

[MacMan31]

I have adapters to be able to use 6SN7 tubes in my Echo Mk2. Any recommendations?

 

[Honeypot]

I have adapters to be able to use 6SN7 tubes in my Echo Mk2. Any recommendations?

Not advisable...
6sn7 doubled the current draw.
6sn7 has 2.5 times the plate voltage.
So... Nope, not compatible... The 2nd would make the tube to perform suboptimally, the first would put the amplifier power supply in a strain.

Peace

 

[MacMan31]

Not advisable...
6sn7 doubled the current draw.
6sn7 has 2.5 times the plate voltage.
So... Nope, not compatible... The 2nd would make the tube to perform suboptimally, the first would put the amplifier power supply in a strain.

Peace

Hmm okay. I see the same tube types are used in the Valhalla 3 and some people are using adapters to accommodate 6SN7 tubes. Maybe it's a different situation for the Valhalla 3.

 

[Honeypot]

Remember the echo will not provide enough juice to power 12au7 properly.

I was wrong about this. My apologies.

 

[MacMan31]

I was wrong about this. My apologies.

I have adapters to use 12a*7 tubes.

 

[Honeypot]

I have adapters to use 12a*7 tubes.

12AU712.6V (pins 4-5 in series)150 mA
12AU76.3V (pins 4+5 to pin 9 in parallel)300 mA
6922 (aka ECC88)6.3V (pins 4-5)300 mA
I don't just made it by calculating, I even tested it.
Sometimes you can be so biased by previous experiences that it's hard to admit.
I stated a few times in this thread 12au7 were harder to drive than 6922, but there was always something scratching on the back of my head. Today I tested it and I got surprised.
So happy 12au7 on echo guys. Just use a properly working adapter and try to avoid tubes with high filament resistance.
Peace