[AnyDave]

I have a pair of Mazda 6V6 which sound great, not the last word in technical performance but very nice tone.

I think that's a good way of describing the RCAs, although I suspect they are probably not as good as the Mazdas.

 

[JTbbb]

L0rdGwyn,

It seems there are some capacitors unavailable which are listed in your BOM

The part is - Rubycon 450 VDC - 220 uF 7.5mm lead spacing Aluminium Electrolytic Capacitors - Radial Leaded.

It appears there are alternative Rubycon capacitors with the same 450 VDC - 220 uF 7.5mm. There’s one with a 12000 hours life rating rather than the 5000 of the original quoted part.

Are they ok to use?

 

[mattiastomas]

For the nos rca 6550 I’m seeing 2 version, the coke bottle version and the more regular even barrel versions.

From what I see I should be going for the coke bottle version? I wonder if there’s any difference in sound

 

[L0rdGwyn]

L0rdGwyn,

It seems there are some capacitors unavailable which are listed in your BOM

The part is - Rubycon 450 VDC - 220 uF 7.5mm lead spacing Aluminium Electrolytic Capacitors - Radial Leaded.

It appears there are alternative Rubycon capacitors with the same 450 VDC - 220 uF 7.5mm. There’s one with a 12000 hours life rating rather than the 5000 of the original quoted part.

Are they ok to use?

https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-17646020

https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-18005978

 

[goldwerger]

For the nos rca 6550 I’m seeing 2 version, the coke bottle version and the more regular even barrel versions.

From what I see I should be going for the coke bottle version? I wonder if there’s any difference in sound

Afaik the coke bottle versions are the older and better models. The later year production has the more regular shape.

 

[JTbbb]

https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-17646020

https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-18005978

Apologies, I should of known to search first!

 

[Kdot]

My 6550/KT88 came in and I have been running them all weekend! I love how they look, the coke bottle shape in cute in a way lol. Definitely agree with goldwerger (thanks for the rec!), these tubes are great for deep and dynamic bass, enjoying them a lot! To my ear they are not as smooth as the EL37 but I can enjoy them with more treble focused headphones and still feel like I am getting the mid presence I want.

 

[goldwerger]

My 6550/KT88 came in and I have been running them all weekend! I love how they look, the coke bottle shape in cute in a way lol. Definitely agree with goldwerger (thanks for the rec!), these tubes are great for deep and dynamic bass, enjoying them a lot! To my ear they are not as smooth as the EL37 but I can enjoy them with more treble focused headphones and still feel like I am getting the mid presence I want.

Congrats!

For me the EL37 and 6550 are great two sets to roll to headphones/taste/mood/genre offering such distinctly differentiated strengths and counterbalance

 

[AnyDave]

Congrats!

For me the EL37 and 6550 are great two sets to roll to headphones/taste/mood/genre offering such distinctly differentiated strengths and counterbalance

Sadly, those are the two biggest gaps in my collection. But I'm on the hunt.

 

[goldwerger]

Sadly, those are the two biggest gaps in my collection. But I'm on the hunt.

Half the fun…

 

[AnyDave]

Half the fun…

Well, I've learned a lot about 6550 tubes. Tung-Sol in particular (who made all of the US coke bottle shaped tubes).

 

[goldwerger]

Well, I've learned a lot about 6550 tubes. Tung-Sol in particular (who made all of the US coke bottle shaped tubes).

It’s amazing how every time you chase a new tube and dig in there’s this whole lore and history about the specifics of each model.. yea

 

[AnyDave]

Wow! That a crazy good price. Hopefully they turn out to be good.

I gotta get better at searching for tubes on eBay

Just as a follow-up, checked the GEC KT88s out on a Hickok 539C on Friday and they test well above minimum and the tubes are surprisingly well matched. Quite happy with the way this turned out.

 

[Dixter]

curious if you guys might know how the output wattage changes with different tubes.... and what tube set is the best match for the Tungsten..

 

[leftside]

It’s amazing how every time you chase a new tube and dig in there’s this whole lore and history about the specifics of each model.. yea

Recommended book. Pasquale also has a book on the EL34 and related. I contributed a few pictures. Both books are a wealth of information about these tubes and the manufacturers.
https://www.musica-parole.com/guide-to-the-6l6-6550-kt66-kt88-6550a/