50's Russian 6SL7 and new 6SJ7 tubes, review. Nice glass!

Just a brief bit of impressions on some Russian glass I received recently from a great seller in Ukraine.

First up is the metal base Melz made 6SL7.

And the test LPs were Charlie Byrd Trio: Charlie's Choice and Stan Getz's Jazz Samba.

I usually have a set of run of the mill inexpensive nothing special RCA 6SL7 tubes burning away. I know how they sound as I spend hours listening to my setup. I'm also familiar with these records. They spend a good amount of time on my turntable.

My RCA tubes:

So how did they stack up against the RCA? The difference was pretty drastic. First let me say I wasn't expecting them to outshine what I have. I choose my hi-fi tubes carefully. If I don't like something it goes in my box to sell to guitar players.

The Melz has impressively low microphonics. Great for my phono stage. Sonically they are far more aggressive than my RCA. Very forward. Stan Getz's sometimes harsh tenor sound gets harsher, not in a bad way, just more in your face. I find the RCA tubes to be more clear and relaxed. Since I don't listen to much metal these days, the Melz tubes will go back in the box. I like to relax in my tiny universe.

I bet these will kick some ass in a guitar amp. I do have one Magnatone that used the 6SL7 tube. I have a new RCA in right now and prior to that I had a Sovtek there which I didn't find sounded objectionable at all. I have a feeling the Melz will melt some faces. I didn't find it objectionable for my hi fi either, I just prefer the RCA.

A word about 6SL7 tubes. The big octal 6SL7, 6SN7 tubes are my favorite for hi fi. They relax more for me than the more common and sought after 12AX7, 12AU7 which are obviously more in demand and more valuable. I built my own preamp to use 6SL7 tubes in the phono and line stage, 6SN7 for the cathode follower driving the power amp. I do not covet any vintage or modern preamps. I built mine 20 years ago from a Swedish schematic called "Remus". It's a fantastic circuit! Simple and honest. No Marantz 7 for me, this sounds better to my ears!

Ok next. A tube I'm really picky about. The 6SJ7. My 45 power amp uses these as a driver stage. Also my favorite guitar amps use these, Magnatone Varsity and "B" amplifier of my own design. They have something psychedelic about them, a shimmer, when in a guitar circuit. I thought it was an Echoplex I used to have but that's gone and that characteristic is still there on my recordings. I don't get it with other amps that don't use these.

So I have the fancy 5693 red RCA 6SJ7 tubes in mine. I love these for hi fi, guitar I prefer the standard 6SJ7. I have a set of metal base Sylvania 6SJ7s that I rejected in this circuit after 10 minutes. I missed the warmth and euphonic quality of these red tubes:

So I got these Russian babies. Cheap as a bag of fancy chips. No joke. A couple bucks each. How do they stack up?

I wasn't hopeful. But....they are pretty damned good! Again more forward and aggressive but not like the 6SL7 tubes. The sound was nice and round, not cold or harsh like my Sylvania tubes. In a pinch I would gladly burn these up. There is no markings on these, just a #7 in a box on the side. Charlie Byrd's guitar sounded nice and round, the percussion deep and warm with a nice top end. No, they don't beat my RCAs, but they don't offend me one bit either.

So, hope this was helpful! I will try these out in my guitar amps and do a bit about that as well. And remember just because something doesn't work for me doesn't mean it won't work for you. Give these a try if you are curious! I'd love to hear your impressions.

JB

Sprague Vitamin Q capacitors. Old school paper in oil magic for your hi fi!

Hello there tube amp heads.....

This is a little post about the legendary Sprague Vitamin Q paper in oil capacitors. I used to have dozens of these and at one point used to swap caps in and out of my hi fi amps when I had that kind of time. I was never all that impressed with the Vitamin Q caps in the past myself but decided to give them a go again now that I only have one system that I know quite well.

These arrived yesterday and I threw them in to my lovely single ended 45 tube amp.

When you have such a simple circuit like this, every little change makes a difference. For instance, the 6SJ7 driver tubes pictured lived in this amp for a day. They are Sylvania. Really nice tubes. I prefer my 5693 RCA Red series tubes by far so they went back in the box! The Sylvania version I love in a guitar amp. Big, open sound but for my hi fi I found them a bit harsh.

The signal caps were Sprague polyester PS type, .1@600V. I hate the 715P series that has been so popular for the last 30 years. The 716 is better but if I gotta use Orange Drops they gotta be PS types. I find them to be smooth, detailed and musical. Plus they are warm which I need and they don't sound harsh like the beloved 715.

Now the 715 in a mushy old amp? That can work. Not saying they are trash, remember, everything is a relationship so they work for some amps just great.

So when I audition a new cap, tube or transformer, the first thing I do is pick a record I've been listening to for many years of my life, preferably something with vocals. In this case it was "Rastaman Vibration" by Bob Marley. First question is how does Bobs voice sound? Can I make out the words clearly? Second is how does Aston "Family Man" Barrett sound? Does his bass sound natural.

First listen is terrible. No definition, crap bass. But, the amp had also been on a mere 3 minutes. When auditioning a cap let it burn at least an hour. When you rebuild an amp, you must give it time!

So I went about my business and came back to it after a few hours. Liquid.... That's the word I use. Bobs voice sounds clear and natural and the bass is big and fat. The bass however, does have a bit of flab I didn't notice before. These are bigger caps than what I had in there (.15 rather than .1) and I could go down to .05 and get my bass needs met. But I will continue to listen to records and see if it works itself out. As I recall, these Vitamin Q caps got better with weeks of use.

So the jury is still out. Do I spend $30 a cap on Jensen Paper in Oil? Are those worth it? (the answer is YES in my opinion. Those sound beautiful.) Or do I keep on keeping on with these surplus store gems? Time will tell and I will tell you later. For now I dig them about 85%.

And on a final note. Are paper in oil caps worth it in your guitar for tone caps? No.... Those merely bleed a little high end to the copper pipes in your walls. You can get a 50 cent ceramic to do that job. That's all marketing ladies and gentlemen......

JB



And instant update....That was fast!

Listening to my favorite Coltrane record, "Crescent". Side 2..... I wore out my first copy ,I love this side that much.

Jazz has a wonderful way of mixing itself. At least in a quartet fashion. The bass and low drums are the lows, the piano and sax are the mids and the ride cymbal are the highs. Coltrane sounds like he's hanging out in my little apartment playing. How the hell did he get that sound is beyond me! So warm and beautiful on this record. Jimmy Garrisons bass has authority and clarity and McCoy Tyner....crystal clear. The second song on side 2 is called "The Drum Thing". All about Elvin. Such a beautiful, dark drum sound. That piece moved me to change the way I make music. Oh yeah, this is about some caps.....they've been burning in all night. I'm in love.......