POST COVID-19 RECOVERY
I’m doing a little better all the time in my Covid-19 recovery phase. My post Covid-19 symptoms are reducing in intensity and frequency, so things are going in a good direction.
I'm hoping to be fully recovered in the next three to four weeks, so I can resume more of my normal activities, and get some more audio writing in.
AUDIO NOTE (UK)
In my "Initial Listening Impressions: The Audio Note (UK) CD 2.1x/II Level Two Red Book CD Player!" post, I said, "The musicality of Audio Note (UK) digital is not a gimmick, it is for real, and I am very excited about it, because really, this is the first time in my own home that I've had something playing Red Book CDs that actually passes the test of musicality, and by doing so has both simultaneously upended what I thought about Red Book CDs, and made me happy while listening to the music on them."
I've been trading a few emails back and forth with Peter Qvortrup and Darko Greguras at Audio Note (UK) about digital Red Book playback about the "why" of their digital players sounding so musical.
I've got a bit of background from Peter now on the basics of the Audio Note (UK) approach to digital, so I'll be writing that up before long.
Also, Darko is going to write up a technical discussion of the Audio Note (UK) CD 2.1x/II Level Two Red Book CD player for me, tell more about their technical approach to digital as you move up to more advanced digital products in the Audio Note (UK) product lines, and some new ideas they are exploring.
The feature review for Positive Feedback is still quite a ways off for the Audio Note (UK) CD 2.1x/II Level Two Red Book CD player (probably the fall timeframe), as it falls into my review queue after the Pass Labs XP-12 line-level preamplifier, whose own feature review for Positive Feedback is also quite a ways off.
In the meantime I will be looking forward to telling you more about all things digital with Peter Qvortrup and Darko Greguras, and why their digital players sounding so musically natural!
FENDER
In my recent "More Adventures with NOS vacuum tubes for the Fender '65 Princeton Reverb reissue guitar amplifier! Postscript added." post I described substituting the stock tube complement with a NOS Sylvania tube set.
Now that I've got some run-in and playing time on the NOS Sylvania tubes, I have to say I'm really impressed with what I'm hearing. Rich, smooth, warm, and just a great sounding tube complement for jazz.
In fact, I'm so pleased with the outcome, and how my Telecaster is sounding through the '65 Fender Princeton Reverb reissue amp, that I may just leave things alone for a while and enjoy what I'm hearing before trying any more mods.
It's really nice when things work out like that!
LEBEN HI-FI STEREO COMPANY
Next up for its feature review at Positive Feedback is the new Leben CS600X integrated amplifier. It's fully run-in now, so I'm going to start working on that feature review this week, assuming my energy levels hold up.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2019/10/PA120009-1024x768.jpeg)
The new Leben CS600X integrated amplifier.
Like the Leben CS600 integrated amplifier I've owned for over a decade now, the new Leben CS600X is a great integrated amplifier, a worthy successor to the CS600, and sounds magnificent with my vintage Altec A5 Voice of the Theatre loudspeakers.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2019/10/PA180001-1024x768.jpeg)
Leben CS600X in my vintage Altec A5 Voice of the Theatre AV system.
SOPHIA ELECTRIC VACUUM TUBES
I had thought I'd include my observations on the performance of the Sophia Electric KT88-ST tubes, EL34-ST tubes, and 12AU7 in the feature review for Positive Feedback of the Leben CS600X.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/01/P1190046-1024x769.jpeg)
Sophia Electric blue glass long-life KT88-ST vacuum tubes.
However, after giving it more thought, I want to do a feature review of the CS600X with its stock tube complement first, and then follow up with a dedicated feature review of the Sophia Electric KT88-ST tubes, EL34-ST tubes, and 12AU7 in the new Leben CS600X and the original Leben CS600.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2017/08/51-Sophia-EL34-ST-1-682x1024.jpg)
Sophia Electric EL34-ST
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2019/12/PC160030-1-768x1024.jpeg)
Sophia Electric 12AU7
That way I think I can say something more meaningful and detailed about the Sophia Electric KT88-ST tubes, EL34-ST tubes, and 12AU7 in the new Leben CS600X, and the original Leben CS600.
The performance of the Sophia Electric tubes is noteworthy, and I think it is worth digging in a little deeper so I can tell you the full story about them rather than just some brief comments.
PASS LABS
After the Leben CS600X integrated amplifier and Sophia Electric vacuum tubes feature reviews for Positive Feedback will be the feature review of the Pass Labs XP-12 line-level preamplifier for Positive Feedback.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/01/P1180021-1024x768.jpeg)
Pass Labs XP-12 line-level preamplifier.
So far I've been listening to the Pass Labs XP-12 line-level preamplifier in my bedroom system with my vintage Altec Corona 832A corner loudspeakers, and it has excelled with each amplifier I have tried it with: the First Watt SIT-3, the Pass Labs XA25, and the Leben CS600.
The Pass Labs XP-12 line-level preamplifier seems to be a very flexible preamplifier, and seems to get the best out of whatever I've partnered it with, not to mention it is just a joy to use because of its well thought out design.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/01/P1290043-1024x768.jpeg)
First Watt SIT-3 stereo amplifier.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/01/P1180038-1024x768.jpeg)
Pass Labs XA25 Class A stereo power amplifier.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/02/P2170001-1024x769.jpeg)
Leben CS600 with "pre in" switch on the far left.
What I would really like to do is try the Pass Labs XP-12 line-level preamplifier plus the Pass Labs XA25 stereo amplifier with my Tannoy Westminster Royal SE loudspeakers, as I have a hunch that would make for a nice match.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2018/09/P9230043-1024x682.jpg)
Chad with the Westminster's and Stokowski Altec's.
That is a huge endeavor though, as I have to move the heavy vintage "Stokowski" Altec's with their Duelund CAST tinned-copper crossovers out of the system, and reinstall the equally heavy Tannoy Westminster Royal SE loudspeakers with the their Duelund CAST crossovers in their place in my living room.
I don't know if I can do that without help, as when I put the Altec's in the West's place in my living room, my buddy Chad helped me do it, as it was quite an effort.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2017/12/10-Wests-683x1024.jpg)
Tannoy Westminster Royal SE loudspeakers.
At least that's the plan for now, as I really want to listen to the Pass Labs gear with my Westminster's.
OTHER STUFF
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/02/P2040018-1024x768.jpeg)
Ultimate Ruby Mica capacitors in a doubled pair.
As I get caught up a little more after being sick from Covid-19, I want to tell you about the doubled pair of Ultimate Ruby Mica capacitors Yazaki-san sent me to try in the SPEC RSA-M3 Real Sound Amplifier.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2019/11/PB210003-1024x768.jpeg)
Spec RSA-M3 Real Sound Amplifier
In the photo above you can see my SPEC RSA-M3 Real Sound Amplifier with a single pair of the Ultimate Ruby Mica capacitors, which I thought made for a really nice improvement.
I have received several reports from the field that a doubled pair of Ultimate Ruby Mica capacitors is even more of a performance boost for the SPEC RSA-M3 Real Sound Amplifier, and I'm looking forward to hearing a doubled pair for myself.
I may even give SPEC RSA-M3 Real Sound Amplifier a try with a tripled pair of Ultimate Ruby Mica capacitors just for kicks.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/02/P2260037-1024x768.jpeg)
Leben RS-30EQ phono equalizer.
I also want to tell you more about tube rolling results in my Leben RS-30EQ phono equalizer when I get caught up a little bit more.
I've been enjoying my Leben RS-30EQ phono equalizer for over a decade, it is a great design, and is of course a great match to the Leben CS600 or Leben CS600X integrated amplifiers.
![](https://jeffsplace.positive-feedback.com/wp-content/uploads/2020/02/P2230002-1024x769.jpeg)
NOS vacuum tubes for Leben RS-30EQ.
I bought a big stash of NOS vacuum tubes for my Leben RS-30EQ phono equalizer, so it will be fun exploring them more in the future and telling you about it.
Ok, well I guess that's all for now.
I hope you all have stayed safe and well during the Covid-19 pandemic, and as always, thanks for stopping by, and may the tone be with you!