Feliks Audio Echo (new budget OTL amp)

Apr 28, 2025 at 7:22 AM Post #616 of 622
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.
 
Apr 29, 2025 at 7:46 AM Post #617 of 622
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...

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Apr 30, 2025 at 12:47 AM Post #619 of 622
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!
 
Apr 30, 2025 at 9:28 PM Post #620 of 622
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...

DSC_1542.JPG

Where did you order these from?
 
May 2, 2025 at 12:00 PM Post #621 of 622
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.
 
May 8, 2025 at 2:00 AM Post #622 of 622
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!
 

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