Dayton Hybrid tube / integrated amp. Question on replacing tubes.

[DaveElson]

Hello there,
I just purchased the Dayton HTA208T Hybrid amp, along with the Dayton USB Audio DAC (DAC01).
The difference through my computer either just online audio, local files or CD Rom is great compared to what I had before.
I see that one of the reviewers at Parts Express stated he / she changed the "cheap Chinese tubes". I have searched and seen one supplier of replacements, does anyone have a favorite supplier of such?
Also - I chatted with Parts Express on Friday and asked how to replace. I was told to just pull the tube out, but there is a guard and everything seems firmly attached. Can the guard be removed?
Finally, as I type this - I keep getting an Invalid Server Response error message and have to click ok to carry on - is this me or Parts Express?
Thanks.

[guitar maestro]

Take off the little acorn nuts and see if you can remove the clear plastic guard things. Then just pull up on the tubes while very slightly rocking them side to side (very very slightly, like 1°-2°).

https://www.tubedepot.com/

[DaveElson]

Thank you - to be honest I hadn't noticed those. Thanks for the link too.

[Kornbread]

Per PE's rules, no linking to a possible competitor but I've have found TubeDepot to be very helpful in most things tube related. I cannot verify this, but if this cheap hybrid amp is like most of the others, the tubes are only used 1) for show and 2) to actually color the sound before it enters the mosfet finals. Boy has a similar tube/hybrid amp for his computer monitor and we would find your tube swapping findings most interesting.
For what it's worth, if not going NOS, most new tubes are now made in Russia or China, including old-time famous brand names like $ Mullard.
With lots of help from TomS and Pwr ryd, I ... we ... built this universal tube amp http://diyaudioprojects.com/Tubes/Un...-Preamplifier/ and although pwr ryd points out this circuit, as is, is not optimized for all the tubes it can use, it didn't take long to hear the difference for myself. Rowing about a dozen tubes through the thing produced a huge difference in the sound 'flavor', not to mention the gain, in the 9-pin 12**7 family.

[DaveElson]

Kornbread
Thanks for replying. I have no experience with tube amps - to build one would probably be too difficult (I have very little experience soldering etc) although one day I may try.
I'm aware of the "fake" tube complaints, I think a Monoprice was considered such. I can say this sounds great, even with these cheap tubes. I trust Parts Express, and while I've not looked at a schematic, I'm happy with this.
Without trying it either:
a)Turning it on without the tubes, or b) fresh replacements - I don't know how I'd know if the tubes were for show. Anyway - I didn't buy this uninformed.
I'm playing a flac concert from the Grateful Dead through it right now from my PC, and it's tons better than the one it replaced.
One day I might upgrade it, but for now I'm happy. Also re the link - Parts Express stated that they didn't hold replacement tubes - so they shouldn't have too much of a complaint.
Edit: Can anyone tell me what NOS stands for? I'm also copying and pasting the review comment that led me to look at replacing the tubes.

"Bought an open box at a discount, it clipped badly(probably why it was returned), replaced cheap chinese tubes with Phillips E80CF NOS and this amp came alive, warm, loud and no distortion. Great product." Made by TEKS on 3/9. Hope he / she doesn't mind me copying.

Finally - Parts Express states this:
The Dayton Audio HTA20BT combines the efficiency and power of solid state class D amplifier topology with the warmth and character of a vacuum tube preamp section. The results are a delightfully articulate and natural sound that is sure to please even the most refined ears.

[Dwight]

New old stock, maybe decades old but never used

[DaveElson]

Thanks Dwight

[Whitneyville1]

We have a "guitar amp doctor" here in town, with lots of NOS Tung-Sols, RCA's, Sylvania's , Muller's, EIC's and even some EITEC/EITEL's, but be sure to bring your wallet! He gets $300 for a pair of "matched" Tung-Sol 12AX7's and maybe ten times that for Muller's. Great tube circuits with good tubes in them sound have "no sound" at all. They should be completely neutral, but most people prefer the "warmer, softer" sound in pre-amps. That's fine if it's what you want. I splurged for a Bottlehead Labs phono pre-amp a few years back and I love it. An analog front-end with an analog source does "make sense" and can sound very, very good. BTW, I figure those Tung-Sol tubes are at least 40 years old, and so are the "Red Label" RCA's.