Except for the stock pair and the Amperex holland E180CC's I just received; I've left the ta-20 on for a week while testing a particular tube pairing for burn in. With the Amperex, I don't think that much time is needed
they're clearly better than all of the others. The Amperex Hollands have completely different sound and really more aligned with what I was expecting when I got this amp. Everything is tighter, the highs are controlled (without EQ), soundstage larger and just has an overall more pleasant sound.
That's great to hear, it is easy to be fascinated with the sound of a new tube before it has turned only to find it isn't sounding long term as you thought it did at first.
What are the rest of your listening system components and headphones?
So after y'all ranting on about the E180CC tubes i decided to take the plunge as well;
https://www.ebay.com/itm/133642391945?hash=item1f1db51189:g:9qwAAOSwiftgBwl0
Will be interesting to see how the "SQ" tubes sound, as i've read many places that they're special (more than in name)...
Both of your excellent E180CC finds have been in my eBay cart for a long time, but there are only so many tubes one can buy at a time before getting tube overload, which I've also done with the TA-20.
Which is why it is so wonderful that we can all share our finds and compare them to other shared finds to help us all focus on our next purchases. I had trimmed down my eBay cart to less than 50 after ordering the E180CC, I figured I was done for a while, then Xduoo drops the TA-26, and I am back up to 89 items in my eBay cart!
I'll fit in both E180CC's over the next 2 months and report my comparisons here too
Oh by the way, and this goes out particularly to
@hmscott; You guys are killing me with your TA-26 impressions as well, and it being lot more "tubey" than the TA-20.
So now i've ordered one..
I foretell bigger tube expenses in my future as well now..lol
Congratulations on your new TA-26!!
Here is what I've bought and received so far for the TA-26, which are already teaching me about the different variations of the 6N5P (6AS7G, 6080, 5998, 7632...) and 6N8P (6SN7 GT/GTA/GTB...) that come with our TA-26's:
Sylvania 6SN7GTA received 1/9, Cost $81.19
6SN7 GTA SYLVANIA NOS SAME DATE CODE TALL GLASS
TUBE1) 3000/3000 uSIEMENS & 7.6/7.6 ma
https://www.ebay.com/itm/143395297531
SYLVANIA VT 231 6SN7 GT NOS Well-Balanced Gm & Ip received 1/9, Cost $137.37
TUBE1) 94/95 uSIEMENS & 10.3/10.4 ma
https://www.ebay.com/itm/133347142184
Sylvania VT-231 6SN7GT ECC33 Mil-Spec Tube - Tested, NOS, Bad Boy, Single Tube received 1/5, Cost $100
This tube has black Bad Boy T plates and foil getters. Date code is from the late 1940's. This was tested on my Dan Nelson calibrated TV-7B. It has been tested for shorts, gas, and transconductance. The tube tests with a reading of 110/110. Minimum is 50.
https://www.ebay.com/itm/255309286381
NEW BOXED MILITARY QUALITY G.E. 6AS7GA DUO-TRIODES FOR AUDIO received 1/6 Cost $42.54
BRAND NEW IN THE ORIGINAL CARTON ROUND GETTER SILVER TOP 6AS7GA POWER DUO-TRIODES MANUFACTURED BY GENERAL ELECTRIC FOR THE US MILITARY - ORIGINALLY USED AS A REGULATOR, THEY HAVE FOUND WIDE APPLICATION FOR AUDIO AMPLIFIER AND PREAMPLIFIER USE Tested on my recently calibrated TV-7D/U where 36 is minimum tube measured 98/104.
https://www.ebay.com/itm/154779730790
The TA-26 China 6N8P - US 6AS7G -
Russian 6H13C or 6N13S Svetlana tubes are much less expensive, and I've heard can be
very quiet and good sounding, but not great - I'm not sure what that means yet, mine are shipping on the 15th and in shipping for 3 more weeks after that...there are also
Russian 6SN7 equivalents, and I am to be getting one (or two, or more?) instead of a $17 refund on combined shipping, so I'll compare those too.
But, it's clear a lot of money can be spent on the TA-26 tubes, but with careful shopping I was able to get those bargains above, yes those tubes can sell for more, so I watch for the measurements - ask for the test results if not listed, but I've found over time if a seller doesn't list the measurements they probably can't provide them. Many "from the case" sellers won't or can't test, and assume New In Box / NOS from case are as good as new. Same as for the TA-20 tubes, with the TA-26 tubes I'm buying NIB or 100%/100% measuring NOS tubes.
The TA-26 sound is different than the TA-20, very enjoyable too but unique, and the stock tubes while nice and tubey can be "sharp" at the edges - as soon as I swapped in the first 6SN7GT VT-231 (late 40's) tube, the "sharp edges" were mostly gone, after installing the GE 6AS7G the "sharp edges" were gone.
I've since tried the other VT-231 6SN7GT and found they are of course very similar sounding, which made the Sylvania 6SN7GTA Tallboy Chrome Dome stand out as so differnt sounding.
The 6SN7GT, GTA, and GTB variants have differeces in their specifications - with the GT to GTA jump the largest - but I need to put in more reading time before I can say exactly what all those differences are. The maximum plate voltage is the big one, I've learned that, but I've also learned that our Audio application doesn't "tax" these tubes, so even though the maximum Plate voltages are different between the GT and GTA/GTB we don't need to worry about that with the TA-26 - I need to confirm that with Xduoo, but first more reading, and listening!
BTW, the GE 6AS7G is in a smaller glass envelope, with straight sides instead of the billowing stepped glass of the stock 6N5P. And, the GE 6AS7G is much smaller than the traditional stepped envelope, but it runs at about the same temperature of 143F. The GE 6AS7G still "towers" over the 6SN7GT, but when I put in the Sylvania 6SN7GTA Tallboy Chrome Dome - the GE 6AS7G is now smaller than the tube in front!
The RCA 6AS7G is the "standard" and should be a first purchase, but I couldn't find any not overpriced when I was shopping for my first TA-26 tubes, so I went the Russian tube route. I've since negociated splitting some Quad/Pairs for purchase next month. Be sure an look for and ask for 5250/5250 mhos as a minimum target for your RCA 6AS7G, as the 100%/100% 5800/5800's are not to be found, althought I am going to keep looking
When you get your TA-26, be sure to be aware that with full DAC output some headphones will have a very small usable Volume range - between 8-9 o'clock, turning down the DAC output with onboard attenuation if you have a Pre-mode, or through a Pre-amplifier to control the input to the TA-26, and now I have 9 o'clock to 1-3 o'clock on the TA-26 Volume dial. I wonder if a different resistance value and curve on the TA-26 volume control would help?
