[DJJEZ]

300B is absolutely amazing and is the way to go with TC (and with anything else really).

Agree. 300B is the way

 

[darktooth8]

Referring to tube rolling in my post above, for the Nautilus owners here - what "upgrade" (and I use the term loosely here) tubes do you feel elevated your experience with the Nautilus to a whole new level in terms of bass, dynamics, soundstage and detail/clarity?

I just got done rolling through some tubes - I focused on the pre amp tube as I wanted to have the blackest background I could find. The JJ that came with it was fairly noisy. I am running the nautilus next to computer equipment and the power in the attic isn’t the best.

I found that the long plate NOS Mullard 12ax7 sounded the best, and fairly silent. I’d say this is a great middle point for me balancing quiet and still has that euphoric sparkle…

The 14mm plate 7025 rca and Mullard sound similar. These have shorter plates and coiled wiring to keep it especially quiet. Similar gain to 12ax7. I am using an RCA 7025 right now and dead silent up to 100ohm. These sound almost as good as the long plate Mullard.

I got some NOS 12ax7 telefunken smooth plates to try… they were ok but seemed a bit thin to me. Especially since I’m already using a chord dac which can seem thin. It took away what I love about the nautilus, the deep bass and mid range growl.

As for the power tubes I felt like the new production telefunken black diamond (made by jj) is actually pretty good - a good amount of airiness and does a good job increasing what I like about the preamp tube

I am currently using some KR audio kt 88s and it does seem it does add a bit more air than the new prod telefunken black diamonds but tbh I think the pre amp tube makes a bigger difference.

The rectifier 5ar4 I got some Mullards with the black base. Fairly easy to get… it punched up the bass from the Baldwin tubes that were in it quite a lot.

I’ve spent so many hours with the nautilus and still it amazes me.

You have me curious about a pre amp now…

 

[Badlands]

Originally posted this on the Atrium thread but thought I’d share here as well.

Let me caveat this this by saying my Kenzie OG 2 is the only tube amp I ever heard. Nevertheless, it never ceases to amaze me paired with the OG Auteur. Sublime is a most apt word to describe it. It’s the most revelatory purchase I’ve made in this hobby. Watched Resolve’s review of the OG Kenzie again last night and he nailed the sound characteristics of the amp perfectly. Would love to hear some of Justin’s higher end amps. Atrium or Caldera is what I’m hoping to purchase next for a headphone. We’ll see if I can hold out till CJ NYC so I can demo them but I know myself well enough to say that I may end up making the purchase during ZMF’s November sale.

 

[WillieB]

@ampsandsound , is it possible to use 807 power tubes(with proper adapters) in the BB? I came across a set and read about some cases where people used them instead of 6L6 or EL-34 without issue in other amps.

Tue MIL spec 807s can be used... but I won't be guaranteeing it. Some are less good and will start to red plate. You need Mil spec and would need to monitor for red plating... this said, if they don't red plate... then they can be used. (Again.... an unofficial report ) .

....An update on the 807 pentodes and Bigger Ben. Here they are installed and working. I'm using the Russian Winged C equivalent of 5U4G for rectification and they seem fine. I'm keeping an eye on them for the time being, but they sound great so far. I found the adapters on Ebay from Amptata. They are pretty good, but I would prefer a set from Pulse or the like. Pulse was out of the 5 pin sockets, but they are going to make me a set once they get some in from Japan. As far as sound goes, the bottom end is tight and punchy like 6L6GC, mids are very similar as well, but upper mids and highs are silky and strings just sound outstanding. I hope they don't change much as I really like them so far. We'll see what happens as they run in a bit. The versatility of these amps is so much fun!

 

[intedinator]

....An update on the 807 pentodes and Bigger Ben. Here they are installed and working. I'm using the Russian Winged C equivalent of 5U4G for rectification and they seem fine. I'm keeping an eye on them for the time being, but they sound great so far. I found the adapters on Ebay from Amptata. They are pretty good, but I would prefer a set from Pulse or the like. Pulse was out of the 5 pin sockets, but they are going to make me a set once they get some in from Japan. As far as sound goes, the bottom end is tight and punchy like 6L6GC, mids are very similar as well, but upper mids and highs are silky and strings just sound outstanding. I hope they don't change much as I really like them so far. We'll see what happens as they run in a bit. The versatility of these amps is so much fun!

Keep us posted. Very interested in your results.

 

[ampsandsound]

Looking good. Prob wise to use a 5u4 and not the 5ar4. Keeps the b+ lower

 

[darktooth8]

Looking good. Prob wise to use a 5u4 and not the 5ar4. Keeps the b+ lower

Do you recommend 5u4 on the nautilus over 5ar4?

 

[ampsandsound]

Depends on the sound. The 5u4 is a wetter sound the 5ar4 after and more forward.

 

[darktooth8]

Depends on the sound. The 5u4 is a wetter sound the 5ar4 after and more forward.

Thanks! I ordered some on ebay as I've been eyeing them. I'll try it out!
I got my nautilus second hand and I have to say, thank you. I can't tell you how much I enjoy it.

 

[duranxv]

@ampsandsound - Justin, any opinions on using Elrog 5U4G's in the Nautilus?

This is the specs they indicate on their website, it's a German tube maker that uses thoriated tungsten

ER5U4G

Filament Voltage .................................................................5 V

Filament Current .................................................................3 A

Peak Inverse Voltage .....................................................1550 V

Peak Current per Plate ........................................................1 A

DC Output Current (L-Input) ......................................275 mA

DC Output Current (C-Input) ......................................275 mA

 

[ampsandsound]

One person tried and had arching. Arching would either mean a bad rectifier or that it can’t handle the input cap value. We use 30uf on the first cap. This should be totally safe for all 5ar4s and 5u4s but not 274s. Could have been a fluke but why change. U52s instead. I have a thing for JAN 5U4s personally.

 

[darktooth8]

I placed NOS RCA 5U4G into the nautilus and I can definitely hear what you mean by the sound is wetter vs the mullard 5ar4s. I was imagining adding a liquidness and viscousness to the sound, but in fact its almost just enough to wet the surface. Love the recommendation.
Do you have a favorite tube for the kt88 slot? I got the genelex gold lions this week and there is this slight hum that is there sometimes, not all the time. I wonder if I need to burn the tubes in more, they have about 20 hours on them.
I really really like the KR audio KT88s. Nice silent background and the soundstage is expansiveand airy but still powerful. Upper frequencies are rounded slightly and gives that glow and hum around your ears in the right frequencies, especially in the mids on the zmf atrium. I've also tried the JJ KT88s, the telefunken (rebranded jj kt88s with "cryotreatment") which I thought were ok, but I get microphonics in those

 

[ampsandsound]

Tungsol 6550 nos are the easy choice.
GEC TT21 is the all out choice.
I love 6l6gc. But that’s about chasing tone.

 

[linshu1992]

I placed NOS RCA 5U4G into the nautilus and I can definitely hear what you mean by the sound is wetter vs the mullard 5ar4s. I was imagining adding a liquidness and viscousness to the sound, but in fact its almost just enough to wet the surface. Love the recommendation.
Do you have a favorite tube for the kt88 slot? I got the genelex gold lions this week and there is this slight hum that is there sometimes, not all the time. I wonder if I need to burn the tubes in more, they have about 20 hours on them.
I really really like the KR audio KT88s. Nice silent background and the soundstage is expansiveand airy but still powerful. Upper frequencies are rounded slightly and gives that glow and hum around your ears in the right frequencies, especially in the mids on the zmf atrium. I've also tried the JJ KT88s, the telefunken (rebranded jj kt88s with "cryotreatment") which I thought were ok, but I get microphonics in those

My fav is actually the JJ kt88s. Compared to gold lion or Mullards, they have the widest soundstage but with a little thinner mids. The old pair has some microphonics which got super annoying and I bought new ones. No noise at all. The sound got tighter and cleaner. I was tempted to buy a new set of all the tubes now.

 

[darktooth8]

Tungsol 6550 nos are the easy choice.
GEC TT21 is the all out choice.
I love 6l6gc. But that’s about chasing tone.

Cool. thank you! I'll give these a try. The current KR audio tubes I'm using are kind of expensive and rare to find even on ebay