[roderickvd]

If you don't intend to roll any of the components, then I don't understand your post regarding your investigations on the Jantzen Audio 8.2uF 800V Z-Silver Capacitor?

I don't think the audio caps in the power section are overkill, in the meaning of "overkill" as "too much of something good". Putting audio signal caps there is the wrong application for those caps and does not bring any particularly goodness to the power supply function. The new Panasonic power supply caps I got in the mail today, now those may be overkill because other, cheaper power supply caps might have been good enough.

I agree on your assessment about "stock on hand" as well as marketing material, which in fact xDuoo does tout on their pictures. As for paying attention, it seems to me that attention was paid to make it marketable and work well enough, not to make it the best technical selection even though the Panasonic FR and Nichicon FW cost about the same.

Don't get me wrong, I do think that xDuoo paid more attention than average and I compliment them on that. But even then designers work within the boundaries of what is commercially interesting to the company, with most always room to do better technically in some respect.

 

[hmscott]

...I am gonna give the caps some more time before i swap them for the Jantzen caps, and at that point any changes should be apparent. At least when comparing Mundorf to Jantzen.
However, it seems like the stock caps are adequate from my hearing at least But i will update more on this matter later.

If you don't intend to roll any of the components, then I don't understand your post regarding your investigations on the Jantzen Audio 8.2uF 800V Z-Silver Capacitor?

@PetFju 's mention of Jantzen Caps as a replacement for the caps he installed spurred my search to see what he was talking about, and I posted the specific part info I found to confirm that is what he was talking about, and to continue the conversation.

Just because I'm not going first into that experimental void, doesn't mean I am not interested in helping the pioneering efforts along in some way, hoping that I can reap the benefits of success later myself, maybe.

I'm happy with how the TA-20 sounds with E80CC/E180CC tubes, and in comparison to the best tube combinations I've found so far for the TA-26 - side by side the TA-20 is keeping up nicely.

Yes, I don't want to mess around inside either the TA-20 or the TA-26 and lose that Xduoo finely tuned edge of audio performance I am enjoying right now, but I will participate in the discussion about potential parts rolling, the same as I have been discussing tube rolling. I don't buy all the tubes discussed either, but I am interested in and will research the options available.

 

[Ufanco]

Thank you both for the help. I checked ground on the ta20 and seems fine decided just to keep using the Oriolus ba300 as a preamp. I know it sound like a weird setup by I like the way it sounds and in the end that’s the most important thing.

​

 

[roderickvd]

Little update on recapping the power supply: the Panasonic FR does *not* work -- do not put them in. I don't own a scope but I think the SMPS becomes unstable because the ESR of the FR is too low. There is erratic switching of the relays and the control panel doesn't work well at all. Not good!

I ordered some other caps with the same ESR as the stock Nichicon FW's: the 4700μF 25V Nichicon PW and 35V Nichicon KW. The former is made for SMPS duties, the latter is the higher audio quality version of the FW. I will report back once I have received them and got them in. Larger capacitance would be nice, though not strictly necessary for SMPS duties.

If the SMPS doesn't like larger capacitance either, it might fail to start up. For that case I also put some Rubycon ZLJ's 3300μF in my basket.

 

[Laines]

Hello,
Im using the MT-602 pre-outs for my powered desk speakers. When I turn on my desk speakers before the MT-602 I get a really loud "pop" when the MT-602 turns on. In the documentation from the MT-602 they mentioned a "mute circuit" which should prevent exactly what's happening.

Do I have a faulty unit, any ideas?

 

[roderickvd]

Amidst these SMPS / power supply capacitor compatibility woes, I got another idea: why not cut the SMPS out of the equation and draw 12V from an external, low noise, linear power supply? I'll be in touch... looking for a part to replace the current AC power socket + button snap-in with a DC power socket.

Edit: couldn't find one so I'll ask a colleague to 3D print one, with a through hole for a DC jack.

 

[hmscott]

Hello,
Im using the MT-602 pre-outs for my powered desk speakers. When I turn on my desk speakers before the MT-602 I get a really loud "pop" when the MT-602 turns on. In the documentation from the MT-602 they mentioned a "mute circuit" which should prevent exactly what's happening.

Do I have a faulty unit, any ideas?

If you are curious you could ask service@xduoo.com

I'd assumed the mute circuit was for the headphones output only - do you hear a thump in your headphones when you turn on the MT-602 with headphones connected?

For now I'd simply follow the age old wisdom and turn on your AMP after your source has gone through it's power on cycle and everything is working ok. You never want to turn on your final amplifier 1st - to avoid thumps and squawks in the speakers. Even if the amplifier is in the speakers

 

[hmscott]

Amidst these SMPS / power supply capacitor compatibility woes, I got another idea: why not cut the SMPS out of the equation and draw 12V from an external, low noise, linear power supply? I'll be in touch... looking for a part to replace the current AC power socket + button snap-in with a DC power socket.

Edit: couldn't find one so I'll ask a colleague to 3D print one, with a through hole for a DC jack.

I am pretty sure the TA-20 / TA-26 use AC - 6.3VAC powered - not DC powered - tube heater power...and there are other functional reasons for the AC power to be connected to the transformer windings, besides powering the SMPS.

I don't think you can replace the TA-20 AC power with DC without a bunch of additional modifications.

 

[roderickvd]

That is an excellent point. You are right.

 

[Ufanco]

Went back and listened to some of the 12ua7 tubes and it made me realize how mush better the 12bh7 sound in the ta20. Even my past favorites like the pinnacle 13d5a and Amperex ecc82 are not in the same league. If you can afford even the inexpensive cbs12bh7 I would highly recommend it.
Currently have my eye on a blue tip set of sylvania 12bh7 but already have more tubes than I need. I really need to sell/give some away.

 

[ProAcTivo]

Just some tube rolling. I switch the Tung-Sol 6SN7GTB new production Russian made for a Tung-Sol 6SN7GTB Tall Boy D getter made in USA, not NOS but almost as new. They are a little different in sound. The older Tung-Sol is more refined. More focus overall, vocals more defined a bit forward. Bass less impacfull but faster. I think is cleaner sounding overall. For now im liking it a lot with the RCA 6AS7G. Both are smooth but the newer 6SN7GTB is less detailed, perhaps more easy listening with any kind if music, but i do miss the extra detail that the USA made 6SN7GTB gives. So for now RCA 6AS7G + Tung-Sol 6SN7GTB (made in USA) is my best combo for the TA-26.

 

[jonathan c]

Just some tube rolling. I switch the Tung-Sol 6SN7GTB new production Russian made for a Tung-Sol 6SN7GTB Tall Boy D getter made in USA, not NOS but almost as new. They are a little different in sound. The older Tung-Sol is more refined. More focus overall, vocals more defined a bit forward. Bass less impacfull but faster. I think is cleaner sounding overall. For now im liking it a lot with the RCA 6AS7G. Both are smooth but the newer 6SN7GTB is less detailed, perhaps more easy listening with any kind if music, but i do miss the extra detail that the USA made 6SN7GTB gives. So for now RCA 6AS7G + Tung-Sol 6SN7GTB (made in USA) is my best combo for the TA-26.

… ‘some’ will lead to ‘more’!… have no fear, it’s fun . The TA-26 is a great way to be involved with tube amplifiers - OTL, no less !

 

[ProAcTivo]

… ‘some’ will lead to ‘more’!… have no fear, it’s fun . The TA-26 is a great way to be involved with tube amplifiers - OTL, no less !

Yes i know. What have i done to myself

 

[Ufanco]

… ‘some’ will lead to ‘more’!… have no fear, it’s fun . The TA-26 is a great way to be involved with tube amplifiers - OTL, no less !

I went a bit overboard with tube rolling and bought a bunch of 12au7 before finding the 12bh7 sound better in the ta20. Oh well it was fun to experiment and most of the 12au7 hopefully will find new homes.
Just checking in to see if anyone has made any progress on 3d risers for the ta20?

 

[Ufanco]

Recently I picked up some 12bh7 CBS 1950’s white tipped tubes. Sadly there was a loud hiss so figured they where bad tubes. They where inexpensive so no big deal.
I was going to just toss them but decided to let the burn in overnight. The next day they sounded much better and was just a slight hiss that was only noticed when nothing was playing. After a week of use the hiss is almost completely gone. These are now one of the best sounding tubes in my collection
This was unexpected and just wondering if anyone had thoughts on why the hiss disappeared ?