This is the fifth post I've written about the Lefson resistors that are manufactured by Xavier Lefebvre in Wormhout, France.

Lefson Resistor family photo: Premium (top), Supra (middle), and Ultra (bottom).

Let me summarize what I've written about Lefson until now:

In my first post I introduced the three product lines of carbon/silver audio resistors that are available from Lefson, the Premium, the Supra, and Ultra.

Lefson Premium Resistors.

The Premium resistor from Lefson is made with a carbon resistive element and silver leads, and is available in values from 0R68 (0.68 Ohms) to 200R (200 Ohms), with power ratings of 4-10 watts.

The 100R Lefson Supra carbon resistor with double-wound silver leads.

The Supra resistor from Lefson is made also made with a carbon resistive element, but with double-wound silver leads, and is also available in values from 0R68 (0.68 Ohms) to 200R (200 Ohms), with power ratings of 4-10 watts.

Lefson 10R Ultra Resistors.

The Ultra resistor from Lefson is made with dual carbon resistive elements, with double-wound silver leads that are gold-coated, and available in values from 0R33 (0.33 Ohms) to 100R (100 Ohms), with power ratings of 6-15 watts.

Xavier sent me two examples of the Supra (100R), Premium (10R), and Ultra Lefson resistor product lines to try in the R4 (100 Ohm), R3-1 & R3-2 (10 Ohm), and R5 (10 Ohm) positions in my vintage Altec A5 Voice of the Theatre crossover project.

All of the Lefson resistors are potted in a fashion similar to that of the Duelund CAST capacitors, and the potting material looks quite similar to the CAST material used by Duelund.

The historic Altec A5 Voice of the Theatre loudspeakers visiting my primary music system.

The Lefson resistors are ultra-high quality, beautiful to look at, and huge!

Lefson Resistors with LP for scale.

Needless to say, it takes a bit of planning to incorporate the Lefson resistors into a circuit!

In my second post about the Lefson resistors I introduced Xavier Lefebvre to you and told you about his early enthusiasm for audio, his background as a sound engineer in various recording studios in Paris, and how his growing interest & experience in modifying & repairing home audio & studio electronics led him to found Lefson in 2013.

Xavier decided he wanted to work specifically on developing fundamental electronic components, such as resistors & capacitors, according to the specifications he believed that best preserved audio signal transmission for high-fidelity sound reproduction, and the Lefson resistors you see here in these posts are the result of his research & development.

Xavier interest in audio electronics expanded to designing and manufacturing audio electronics for both personal audio and professional recording studio use, including preamplifiers, compressors & limiters, equalizers, microphones, and the like, which you can read more about on the Lefson website.

Xavier also opened a service business, Lefson Repair, where he restores, modifies, and performs maintenance for home audio and studio electronics.

10R Lefson Premium silver/carbon resistor at R5.

In my second post I also described installing the Lefson 10 Ohm Premium resistors in place of the Ohmite Brown Devil resistors I had been using in the R5 (10 Ohm) positions of my A5's crossovers, and the positive first impressions the Lefson's made on me.

In my third post I provided some very preliminary listening impressions of the Lefson resistors (with no run-in time on them), describing how I found the 10R Lefson Premium silver/carbon resistors installed into R5 to be much more transparent, detailed, and nuanced, than the Ohmite Brown Devils. I also described how the Lefson’s made recordings sound dramatically more spacious, how imaging was much more vivid & detailed, and how lots more timbral details came through, than with the Ohmite Brown Devils.

I did have a few reservations about the 10R Lefson Premium's at R5 though, as they sounded a little more forward than I like, and I heard more edge on horns than I would have preferred.

The 100R Lefson Supra silver/carbon resistor at R4 in the A5's left crossover.

I also described trying the 100R Lefson Supra silver/carbon resistors, with their double-wound silver leads, in the R4 position of the Altec A5’s high-frequency crossovers.

I found that the 100R Lefson Supra silver/carbon resistors in R4 exhibited all the good qualities of the 10R Lefson Premium silver/carbon resistors at R5, but they didn't exhibit any edginess on horns that I was hearing at R5. I wasn't sure if the lack of edginess I heard between R4 and R5 was due to the different positions in the crossover, or if it was a difference in the nature of the voicing between the Lefson Premium and Lefson Supra resistors, but I liked the result.

As I continued to listen to the 100R Lefson Supra silver/carbon resistors in R4 I became more & more impressed by what I was hearing musically. I noted that from a tempo, melody, beat, rhythm, and, dynamics standpoint, the 100R Lefson Supra’s were a little more ‘real’ sounding than the Ohmite Brown Devils, and I got a very good feel for tempos, changes in tempos, the nuance and ‘touch’ of melody lines, and beat & rhythm from them. The Lefson's noticeably bettered the Brown Devils musically, and the Brown Devils are actually quite good from a musical perspective.

Lefson 10R Premium and 100R Supra resistors installed at R5 and R4, respectively. 10R Ultra posing on the A5.

In my fourth post about the Lefson resistors I reported on a listening session with my audio pals Ron & Leo, who had joined me for some audio comparisons of the Lefson resistors in the A5’s crossovers.

We had a nice afternoon of comparing the Premium, Supra, and Ultra Lefson resistors in positions R4 (Supra) and R5 (Premium & Ultra) in the A5’s crossovers to the Ohmite Brown Devil wirewound resistors.

The consensus was that the Lefson resistors were notably more transparent, had greater resolution of detail, a much greater presentation of soundspace, and a better delineated soundstage.

Lefson 10R Premium and 100R Supra resistors installed at R5 and R4, respectively.

We did comparative listening sessions between the 10R Lefson Premium and Ultra resistors at R5, with the consensus being that the Lefson 10R Ultra resistors were preferable to the Lefson 10R Premium resistors in relatively subtle ways (just generally more refined and natural sounding), and both of them were greatly preferred to the Ohmite Brown Devils.

I also described how I had intended to follow up promptly with more listening sessions to the Lefson resistors, but as bad luck would have it, my elderly OPPO BDP-83 Blu-Ray player that I was using for my reference digital source in my A5 Voice of the Theatre system gave up the ghost and died.

OPPO UDP-203 Blu-ray player - front view.

OPPO UDP-203 Blu-ray player rear view.

That delayed my progress for listening comparisons with the Lefson resistors, as I had to replace my OPPO BDP-83 with a new OPPO UDP-203 Blu-ray player and wait for it to run-in adequately so it could serve as a baseline of comparison.

There was a benefit to the delay of running-in the OPPO UDP-203 Blu-ray player, and that is I was able to get the same amount of run-in time on the Lefson 10R Premium and 100R Supra resistors installed at R5 and R4.

I had originally intended to condition the Lefson resistors on my Audiodharma Cable Cooker, but it turns out my CC choked on the load they represented, and wouldn't cooperate in conditioning them as if they were speaker wire. Alan is researching a way to conveniently condition resisters with the CC. The temporary work around Alan suggested wasn't very convenient, as I could only do one resistor at a time, and I didn't have time to go that route with all the resistors I would have had to condition, so at the moment it's not really a viable alternative for me.

The current state of my Altec A5 Voice of the Theatre music/video system.

So in today's post I thought I'd share with you some brief listening impressions of the Lefson's with my OPPO UDP-203 Blu-ray player, which has now got quite a few hours on it, but probably still a little shy of the 100 hours that I like as a run-in standard.

My vintage McIntosh MC225, a match made in heaven for driving my vintage Altec A5 VOTT's.

First let me remind you of what I'm running for the other electronics in my video/music Altec A5 Voice of the Theatre system.

My restored vintage McIntosh MC225, which I purchased from Yves Beauvais at Vintage Vacuum Audio, drives my Altec A5 VOTT's superbly.

My preamp is the gorgeous Leben RS100 U, which turns out to be quite a nice match to the MC225.

Leben RS100 U preamp with MacBook Pro.

Then there's my new OPPO UDP-203 Blu-ray player doing digital disc duties, as well as serving as a DAC for my MacBook Pro, via it's HDMI input.

Leben RS100 U preamp with Robusto AC power cord & RAS conditioner.

I'm using one of the terrific Sablon Audio Robusto AC power cords (a favorite of mine) to power the Leben RS100 U preamp, with the addition of an Acoustic Revive RAS-14-TripleC NCF Power Conditioner to it (to give the RAS some run-in time).

There'a a pair of Yazaki-san style (shield connected at both ends) Belden 8402 microphone cable interconnects going from my Philips television to the Leben RS100 U preamp, as well as from the RS100 U to my vintage McIntosh MC225 stereo power amp. As an aside, the connection between the RS100 U and the MC225 has to be shielded or it hums.

The interconnects from my OPPO UDP-203 Blu-ray player to the Leben RS100 U are the tinned-copper Duelund DCA16GA wires terminated with Duelund gold RCA's.

The AC power cord for my OPPO UDP-203 Blu-ray player is a Sablon Audio Gran Corona with a quantum filter that is really flattering to digital sources.

The speaker cables from the MC225 to my Altec A5's are single runs of Duelund DCA16GA tinned-copper wire, with no terminations (sounds better that way).

Jazz24

I love the Seattle streaming jazz station, Jazz24, and I have it going all the time when I'm doing things around the house, cooking, or conditioning equipment.

I don't know what gear Jazz24 uses to process its digits, but it sounds very good streaming through my OPPO UDP-203!

Jazz24 streaming jazz radio station - a favorite!

My impressions with the Lefson 10R Premium and 100R Supra resistors installed at R5 and R4 in combination with my new OPPO UDP-203 streaming Jazz24 are extremely positive, reenforcing what I heard from it earlier playing CD's, except it evens sounds better, in fact way better.

Jazz24.

I'm hearing beautiful tonality, tone color that is outstanding, a huge sense of space, a big soundstage with well delineated images, and lots of meaningful musical detail.

The musicality is really outstanding, and pushes my emotional buttons with verve, with a superb rendering of timbral textures, tempos, dynamics, melodies, rhythm, beat, and a terrific sense of the musicians' 'touch' on their instruments.

The combination of sonics & musicality is a real treat!

Also, on Jazz24 the caveats I had about the 10R Lefson Premiums at R5 completely disappeared, no longer sounding a little forward, or edgy on horns, they just sounded superb both sonically & musically, and I couldn't find a nit to pick.

The OPPO UDP-203 playing CD's.

Next I listened to the OPPO UDP-203 playing some of the CD's I was listening to just before my BDP-83 bit the dust, like Chester & Lester, Getz/Gilberto, Bell Evans Trio Sunday at the Village Vanguard, and the When Harry Met Sally soundtrack by Harry Connick, Jr.

I listened to CD's in the UDP-203's Pure Audio Mode, which "reduces any potential interference between the video and audio signals by turning off the player’s video processing and output," and which I thought sounded better for listening to music.

Chester & Lester (Chet Atkins & Les Paul) is breathtaking with the Lefson's in place, and was utterly mesmerizing from a musical perspective, and sounded superb from a sonic perspective as well. This is such a fun album, I really hope someone will release it on a 45RPM LP set (Chad go for it! Please!).

On Getz/Gilberto it was much the same thing, I just fell into a reverie from a musical & sonic perspective while listening, and thoroughly enjoyed the music. I did notice that there was just the slightest amount of edge on the horns on occasion, but it was greatly reduced from what it was previously, so either the 10R Lefson Premiums at R5 have smoothed out with run-in (probable), or the UDP-203 handles horns better than the BDP-83 (also probable), or ... I'm wondering what a pair of Duelund DCA20GA tinned-copper interconnects might do for this vestige of horniness ... I just have a hunch.

Ok, that's it for now, as I have one more post I want to write up for you in a few moments before I call it a day, and retire for the evening from writing.

In the next 3-4 weeks I'm going to be working hard on intensive listening impressions with all the Lefson resistors while writing up my review of them for Positive Feedback, so you can expect more listening impressions along the way.

As always, thanks for stopping by, and may the tone be with you!