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Aiyima T8 valve amp, to grease or not to grease...?

Schlippwhip68

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Hi,
I have recently pursed an Aiyima T8, its a pretty little thing with a decent sound. I have also gone as far as teaming it with Aiyima's A08 amp which is quite versatile in respect of further DAC coupling.


I am in the process of upgraded the stock valve to an GE 5670 and was wondering if anyone may have explored the use of conductive grease such as MG Chemicals (very expensive stuff) on the pins of the valves and if they have found either better or worse results?
 

Blumlein 88

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Hi,
I have recently pursed an Aiyima T8, its a pretty little thing with a decent sound. I have also gone as far as teaming it with Aiyima's A08 amp which is quite versatile in respect of further DAC coupling.


I am in the process of upgraded the stock valve to an GE 5670 and was wondering if anyone may have explored the use of conductive grease such as MG Chemicals (very expensive stuff) on the pins of the valves and if they have found either better or worse results?
I would not suggest that. For one thing tubes have rather high DC voltages involved. Conductive grease may move about and create a path you don't want it to create. All tubes I've ever used fit rather snuggly with mechanical fit. Maybe removing them and replacing them once a year should ensure clean enough contacts I'd think.
 

Yasuo

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Slightly offtopic - I've seen the other version of this amp yesterday (without that base) and it looks gorgeous!
 

raindance

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It would simply be dangerous and not do anything at all to change the circuit design. If you're curious about improving contact with the sockets, you could try: 1. replace the sockets with better ones 2. Buy tubes with gold pins. But you'd probably just be wasting your time.
 

Zek

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Slightly offtopic - I've seen the other version of this amp yesterday (without that base) and it looks gorgeous!
It's a T-8, pre-amp alone.
Sold separately or together with amplifier A-8.

Screenshot 2022-01-11 at 14.44.54.png
 
OP
Schlippwhip68

Schlippwhip68

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I would not suggest that. For one thing tubes have rather high DC voltages involved. Conductive grease may move about and create a path you don't want it to create. All tubes I've ever used fit rather snuggly with mechanical fit. Maybe removing them and replacing them once a year should ensure clean enough contacts I'd think.
The sockets are snug. In fact i was a little scared of the valve exploding via the pressure needed to place it but as with most things, slowly and gently won the union.
 
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Schlippwhip68

Schlippwhip68

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Slightly offtopic - I've seen the other version of this amp yesterday (without that base) and it looks gorgeous!
It is a very nice effort from Aiyima. Even the font on the digital screen is like an 18th century newspaper, very classy indeed.
 
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Schlippwhip68

Schlippwhip68

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It's a T-8, pre-amp alone.
Sold separately or together with amplifier A-8.

View attachment 178183
Its quite an impressive combination. I have had this for a few days. I have to say I like a more anylitical approach to my listening pleasure which is where my Cambridge Audio Topaz AM10 and Topping E30 play a fine role. The T8 has a warmer less detailed leaning but apparently the stock valve is known for being muddy and it is advised from Watford valves UK to replace it with at least a GE 5670 which will in turn clear everything up and give an overall far better presentation.
The A8 is another egg altogether. I ran my Topping E30 with an Hama DTi2105SBTX Streamer as the source with Internet radio station and it was a completely different breed to the union with T8. Much more detailed and precise for the short time i had to listen. That is not to say that the T8 is worse because it is not, it is a warmer sound and to many ears will be easier to listen to for longer periods of time. I have not ran extensively into a listening test but I can say neither one of these two offerings from Aiyima are being sent back for a refund. There is plenty of room to play here.
 
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Schlippwhip68

Schlippwhip68

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I would not suggest that. For one thing tubes have rather high DC voltages involved. Conductive grease may move about and create a path you don't want it to create. All tubes I've ever used fit rather snuggly with mechanical fit. Maybe removing them and replacing them once a year should ensure clean enough contacts I'd think.
Agreed.
 

egellings

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Those conductive greases are meant for low impedance high current applications. In a tube amp, this is simply not an issue at all. Plus, the grease may migrate and cause unwanted leakage/conductive paths. Not recommended. Just be sure that tube socket pins are tensioned properly and that the tube pins are straight. For 7 & 9 pin types, use a tube pin straightener to ensure this. If the tube pins are oxidized, I use emery paper strips to buff them shiny.
 
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Schlippwhip68

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Those conductive greases are meant for low impedance high current applications. In a tube amp, this is simply not an issue at all. Plus, the grease may migrate and cause unwanted leakage/conductive paths. Not recommended. Just be sure that tube socket pins are tensioned properly and that the tube pins are straight. For 7 & 9 pin types, use a tube pin straightener to ensure this. If the tube pins are oxidized, I use emery paper strips to buff them shiny.
Excellent.
 
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Schlippwhip68

Schlippwhip68

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I replaced the stock valve on the Aiyima T8 this morning with an GE 5670 and there is an notable difference in overall performance. Certainly brighter, less muffled and cloudy overall. Cleaner and more presentation in the vocals. The bass has gained a more defined punch but actual extension at least at present does not seem to have any improvement but certainly cleaner. The highs and upper mids are are the biggest improvement. I would be interested to find any experience from members with the GE 5670 and if there is an better valve primarily for dance music in general.
Would the 5963 SYLVANIA GOLD BRAND be a better choice?
 
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markzts

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I have an Aiyima D03 and I'm looking to get a T8 as well to pair with another amp I have. On the 5670, did you pay extra for triode matching, high gain, etc or just the standard tube?
 
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Schlippwhip68

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I have an Aiyima D03 and I'm looking to get a T8 as well to pair with another amp I have. On the 5670, did you pay extra for triode matching, high gain, etc or just the standard tube?
5670 GE TRIPLE MICA NOS VALVE TUBE is the exact name of the tube. In regards to any further info I really cant help at this point, sorry. I also have the D03 and can tell you that the T8/A8 combo sounds alot better especially with this valve replacement but it didn't sound much better with the stock valve, too shrouded in comparison like i was listening to it with my head under a blanket. I'm afraid the Chinese stock valves are not that good at present so I would highly recommend the valve upgrade first but at least the stock valve will get you up and running, after all they didn't have to put one in there did they..
 
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SIY

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5670 GE TRIPLE MICA NOS VALVE TUBE...
As soon as you get to stuff like this, we're talking baseball card collecting. If there really is a sound difference between the tubes (and it may well be completely imaginary), either one of the tubes is bad or the circuit is wildly incompetently designed.
 
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Schlippwhip68

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As soon as you get to stuff like this, we're talking baseball card collecting. If there really is a sound difference between the tubes (and it may well be completely imaginary), either one of the tubes is bad or the circuit is wildly incompetently designed.
No offence but I don't agree with that at all. All equipment in my test is brand new and tubes are from a valid source, and the difference is cat and dog! There are very large audible differences as well as subtle in the sound from tube to other tube. Its also a widely agreed and known fact across the entire planet.
Its a common complaint against Chinese stock valves that they are not clear, dynamically sub par and quite muddy or even muffled. Changing the stock 6n3 out for the GE 5670 has confirmed that complaint to my own ears today and I am no audiophile, its a truth.
 
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Schlippwhip68

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I have an Aiyima D03 and I'm looking to get a T8 as well to pair with another amp I have. On the 5670, did you pay extra for triode matching, high gain, etc or just the standard tube?
In regards to a D03 and T8/A8 sound comparison I found superior low end control, better definition and generally richer sound with the T8/A8 combo.
 

markzts

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I actually have an older class D amp that I was thinking of pairing with the T8 or even just using it as a headphone amp. I may get an A8 or some other MA12070 based amp later if my pairing doesn't work out so well. I was just asking about the 5670 swap as I have basically no tube experience. Thanks for sharing your perceptions.

I mainly got the D03 just to have something with more headroom ( 36V supply ). I listen in a 12 x 16 room with sub optimal placement and sub optimal ears that can't hear as well above 12KHz or so.
 
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Schlippwhip68

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I actually have an older class D amp that I was thinking of pairing with the T8 or even just using it as a headphone amp. I may get an A8 or some other MA12070 based amp later if my pairing doesn't work out so well. I was just asking about the 5670 swap as I have basically no tube experience. Thanks for sharing your perceptions.

I mainly got the D03 just to have something with more headroom ( 36V supply ). I listen in a 12 x 16 room with sub optimal placement and sub optimal ears that can't hear as well above 12KHz or so.
I have not the tested the headphone yet but it is reported better than expected and even trumps the RCA at the rear of the T8 which in turn is vastly better than the D03 RCA implementation. Check Cheapaudiomans review of the T8 online. I would say this could be a good match for most class d amps. This is quite a loud combo T8/A8, I have a 5m x 5m room and going past half way say hitting 2 o'clock on the A8 and around 65 on the T8 is easily loud enough. The T8 goes up to 99 and I have not heard any distortion up to around 70. I have not pushed it any further as I have no need to. I was not convinced by the MA21070 at first but now i am eating humble pie and actually think it is quite impressive but imo...still a long way off good class A/B.
How is the sub on the D03 working out? The A8 also has sub out...
I am also a noobie with tubes like literally in the last week but the GE 5670 is vastly superior to the stock valve. The GE 5670 can be purchased at Watford Valves UK online and ebay for around £20.
 

DVDdoug

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I remember tubes from the 1960's and I even owned a couple of tube amps into the 70's. Tubes used to burn-out occasionally and maybe even come loose in the socket but I don't ever remember anybody "treating" the contacts.
 
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