So has anyone replaced the 6550s in their Ref 10 with KT88s?

[Barry]

So I tried a pair of Shuguang Treasure KT-88Z CBs (burned in 150hrs) in the PS of my ARC REF10 phono and think I like them best of all (v. Sovtek WEs, SED Cs, Shuguang KT-88Zs). Started to compare them directly, back-to-back, to the earlier Shuguang KT-88Zs, but one of that pair went dead after only 125 hours of use. Not exactly enthusiastic endorsing these, as I've never had a PS big tube failure. I have ordered another pair anyway. Thankfully, no damage was done.

I still have SED Winged "C"s in the ARC REF 40 preamp and really have little desire to swap them out for now as I liked them better than the Sovteks, but who knows....

May buy a pair of Psvanes to try later. More to follow if I don't get too lazy and the weather is also perfect for cycling these days. Got 640 miles in last month.

 

[Harlequin]

Most interesting Barry, pleased to read that you survived that valve fail unscathed.

 

[Mike]

So I tried a pair of Shuguang Treasure KT-88Z CBs (burned in 150hrs) in the PS of my ARC REF10 phono and think I like them best of all (v. Sovtek WEs, SED Cs, Shuguang KT-88Zs). Started to compare them directly, back-to-back, to the earlier Shuguang KT-88Zs, but one of that pair went dead after only 125 hours of use. Not exactly enthusiastic endorsing these, as I've never had a PS big tube failure. I have ordered another pair anyway. Thankfully, no damage was done.

I still have SED Winged "C"s in the ARC REF 40 preamp and really have little desire to swap them out for now as I liked them better than the Sovteks, but who knows....

May buy a pair of Psvanes to try later. More to follow if I don't get too lazy and the weather is also perfect for cycling these days. Got 640 miles in last month.

I swapped out the Sovtek 6550’s today and installed my NOS, matched SED Winged C 6550’s (from here: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/283069212072)

Much fleshier sound, slight increase in sweetness, just a touch of warmth. Vocals were the most improved. Vocals and instruments had a greater 3D presentation. I would consider the improvement quite significant.

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[Mike]

Still listening. Loving this change. HIGHLY recommended.


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[Audio 1]

I just ordered a set for my Ref.6 pre and Ref.3 phono-pre.

 

[Bobvin]

There were some problems I remember with the later winged C valves, can anyone speak to when the production began to be sketchy? I know I had purchased some and they caused me some round trip repairs to ARC, but I don't know how old "NOS" needs to be?

 

[Barry]

There were some problems I remember with the later winged C valves, can anyone speak to when the production began to be sketchy? I know I had purchased some and they caused me some round trip repairs to ARC, but I don't know how old "NOS" needs to be?

I have a few dozen of the SED Winged "C"s including newer ones. You should try to avoid anything 2011 or newer (11XX). I've bought new production from reputable suppliers that have very low plate current as measured on my Amplitrex tester using fixed bias that tested as low as 40-80% of spec. They also may have a very poor vacuum. I've had ones gas out even before I used them. The best quality SEDs were sourced from ARC and were well worth the additional cost. They'd test north of 100% even after 1,000 hours of use.

It's not critical that the tubes be exactly matched as ARC REF PS 6550 tubes are autobiased, but I match mine anyway.

 

[Elberoth]

Some 10+ years ago, when I still had my ARC Ref 3 preamp, I had great success with NOS Tung-Sol 6550 Black Plate from the 50s. Those tubes got hard to get nowadays AFAIK.

 

[Mike]

Some 10+ years ago, when I still had my ARC Ref 3 preamp, I had great success with NOS Tung-Sol 6550 Black Plate from the 50s. Those tubes got hard to get nowadays AFAIK.

Found a matched quad of these this morning. Going to try them.


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[mep]

Geez, I have a NOS GE 6550 that came from ARC as a spare for a D-79 I used to own. I wonder how that would sound in the Ref 6?

 

[Mike]

Geez, I have a NOS GE 6550 that came from ARC as a spare for a D-79 I used to own. I wonder how that would sound in the Ref 6?

I bet they would be great.


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[nc42acc]

Mark it will sound fantastic! This is what I am using in my REF5SE. Try it you may like it...….

Geez, I have a NOS GE 6550 that came from ARC as a spare for a D-79 I used to own. I wonder how that would sound in the Ref 6?

 

[joeinid]

Hi Mark !!!!

Geez, I have a NOS GE 6550 that came from ARC as a spare for a D-79 I used to own. I wonder how that would sound in the Ref 6?

 

[rrwmd]

[QUOTE
WOW!!! These things are great! Thanks Mike!

=Mike;245924]I swapped out the Sovtek 6550’s today and installed my NOS, matched SED Winged C 6550’s (from here: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/283069212072)

Much fleshier sound, slight increase in sweetness, just a touch of warmth. Vocals were the most improved. Vocals and instruments had a greater 3D presentation. I would consider the improvement quite significant.

Sent from my iPhone using Tapatalk[/QUOTE]

 

[Mike]

Rance, that’s fantastic.

 

[Mike]

Tried a NOS 6550 today. Added quite a bit of warmth. Not as sweet on top as the Winged-C, but certainly warmer.


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[nc42acc]

Mike I ordered a Winged-C- for the REF5SE on your review and recommendation. Thanks for being the Guinea pig for us.

 

[nc42acc]

 

[Mike]

Nice Marty! Keep us posted.

 

[Harlequin]

Mike...I may be incorrect however I kinda read Marty's post more along the lines of I would like to hear about user experience of this implementation before I consider such, rather than, I am in the process of making the swap to KT88's watch this space.