KT 150 valves in a Cayin A 88T mk2

[craka]

Hi all,

Can anyone confirm if I can run KT50,s in this Amp?

I'm currently running KT 120,s.

Anyone done this

craka

 

[custom_made]

I can not see any mention of the Cayin A88T mk2 being compatible with KT150 tubes.
At best you can use KT120 tubes with factory modifications.

AV Hub article

Quote

Cayin’s A88T Mk2 has been heavily upgraded internally and the company now specifies power output when using standard KT88 output valves as 45-watts per channel in Ultralinear mode and 25-watts per channel in triode Class AB1 mode. The glass of the new KT120 valve is 12mm higher than a KT88, the internal plate structure is 10mm longer, the control grid cooling fins are twice as large and the KT120 filament draws up to 300mA more current than the one inside a standard KT88 valve. Because of this, anyone wanting to use KT120s will need to order the unit specially, so that the valves can be pre-installed and the initial bias set by Final Link, which will be an added cost over the base retail price of $2,799. ‘Used in the A88T MkII, the KT120 will deliver unbelievable amounts of clean headroom, low end depth and dynamic punch… and all without overloading,’ Lewis told Australian Hi-Fi Magazine.

For further information, please contact Final Link Audio

More info:

Spoiler

 

 

Edited February 19, 2019 by custom_made

[craka]

I can not see any mention of the Cayin A88T mk2 being compatible with KT150 tubes.
At best you can use KT120 tubes with factory modifications.

AV Hub article

Cayin’s A88T Mk2 has been heavily upgraded internally and the company now specifies power output when using standard KT88 output valves as 45-watts per channel in Ultralinear mode and 25-watts per channel in triode Class AB1 mode. The glass of the new KT120 valve is 12mm higher than a KT88, the internal plate structure is 10mm longer, the control grid cooling fins are twice as large and the KT120 filament draws up to 300mA more current than the one inside a standard KT88 valve. Because of this, anyone wanting to use KT120s will need to order the unit specially, so that the valves can be pre-installed and the initial bias set by Final Link, which will be an added cost over the base retail price of $2,799. ‘Used in the A88T MkII, the KT120 will deliver unbelievable amounts of clean headroom, low end depth and dynamic punch… and all without overloading,’ Lewis told Australian Hi-Fi Magazine.

For further information, please contact Final Link Audio

More info:
Spoiler  
 
Thanks custom_made,
Ive read that.Im not sure what or not needs to be done if anything to power up 150 goodness

[Ittaku]

 

 

The KT150 needs significantly more current again than the KT120. You'd need to beef up the power supply even further than what the modified version supplies, and associated filtering at the very least. There's a good chance other components would need to be modified to suit as well, depending on topology.

[custom_made]

.

Edited February 19, 2019 by custom_made

[Guest Muon N']

Likely, It would need a more capable secondary winding for the heaters power supply to cope with the extra draw on the supply. (other circuit adjustments might be needed also, I don't know)

 

Strange that the data sheet for the KT 150 above doesn't include specs on heater supply, or maybe it was lower down on the page/s.

[craka]

Thanks all for your feedback.Youve answered all my Questions.

[krystof]

Hi, did you finally bought these kt150 for your Cayin?

[craka]

6 hours ago, krystof said:

Hi, did you finally bought these kt150 for your Cayin?

Hi,

No the Cayin cant provide the power to run the KT150,s.

[TerryO]

Hi Craka,

 

I realise you asked the question here but out of interest in the end did you check out the advice you were given about KT150’s not working in your amp with Cayin? 

 

I have a Mystere PA21 Power amp at my place at present and it comes standard with either el34’s or KT88’s, however the owner runs KT150’s in it and it sounds pretty damn good with the big tubes, definitely better than with the standard KT88’s.

 

If your not busy this Saturday arvo and you have time why not bring your amp down to my place (Arundel) and you can try some KT150’s.

 

Cafad will be here as well with a number of different amps that we will be trying out along with an important comparison between Asahi and Corona. 

 

cheers Terry

Edited April 2, 2019 by TerryO

[Guest Muon N']

The possible risk taken if heater windings are not up the the task of supplying the current draw from the KT150's is the transformer insulating material failing and that is not an attractive outcome. It maybe not happen in the short term and may fail over extended use, I'd not even risk it in the short term.

Not without a go ahead from Cayin themselves.

 

Edit: the other option which takes more effort, is to have a reputable tech' that knows valve amps to check the abilities of the transformer heater windings, to see what they are capable of supplying the draw without being compromised.

Edited April 2, 2019 by Muon N'

[Guest Muon N']

I have emailed Cayin and given them the link to this thread, if they only reply to my email I'll copy and past the answer here.

[TerryO]

6 hours ago, Muon N' said:

I have emailed Cayin and given them the link to this thread, if they only reply to my email I'll copy and past the answer here.

Good idea.

 

Cheers Terry

Edited April 2, 2019 by TerryO

[Guest Muon N']

John from Cayin replied to my enquiry, as below.

 

Hi Ian,

 

We donot suggest to use KT150 to replace the KT88 in A-88TMK2. It is because transformer is not strong enough that if you put in KT150 the power transformer will become very hot. It will affect the reliablity of the power transformer in long term use.

 

Thanks and with best regards,

 

John

[craka]

On 02/04/2019 at 11:37 PM, TerryO said:

Hi Craka,

 

I realise you asked the question here but out of interest in the end did you check out the advice you were given about KT150’s not working in your amp with Cayin? 

 

I have a Mystere PA21 Power amp at my place at present and it comes standard with either el34’s or KT88’s, however the owner runs KT150’s in it and it sounds pretty damn good with the big tubes, definitely better than with the standard KT88’s.

 

If your not busy this Saturday arvo and you have time why not bring your amp down to my place (Arundel) and you can try some KT150’s.

 

Cafad will be here as well with a number of different amps that we will be trying out along with an important comparison between Asahi and Corona. 

 

cheers Terry

PMed

[craka]

On 03/04/2019 at 5:58 PM, Muon N' said:

John from Cayin replied to my enquiry, as below.

 

Hi Ian,

 

We donot suggest to use KT150 to replace the KT88 in A-88TMK2. It is because transformer is not strong enough that if you put in KT150 the power transformer will become very hot. It will affect the reliablity of the power transformer in long term use.

 

Thanks and with best regards,

 

John

Thanks very much for doing that Ian.Great info from the source.

Cheers

 

Craig

[Guest Muon N']

That Mystere PA21  amp is interesting, being pure Pentode and not the usual UL or Triode design, a very different amp to most these days.

[Michael T]

Since KT 150s were not compatible but KT 120s are okay, were there any modifications necessary before installing the KT 120s? I am thinking of buying the Cayin A MK2 KT88 and would like to know this as it would give me another tube option and assist me in making my decision. Thanks very much for your input.