Supratek Owners Thread
@sim_audio_nerd I asked Mick about his 6l6 based amp a few years ago. At the time he said he was so backed up with preamp orders he wasn’t making amps. Maybe he would be willing to now. I took inspiration from his 6l6 amp by having a push pull amp made without a phase splitter in it. Since the Cabernet has a great phase splitting transformer in it you can eliminate it in the amp. I highly recommend it! |
If you already have 6sn7 and equivalents you like I would just go with that. If you get curious about 6j5 tubes you can always use an adapter to go from 1 6sn7 to 2 6j5.
If you are someone that likes experimenting with tubes you might want to get your preamp switchable between 6v and 12v. It costs extra but it has allowed me to try out some tubes that I couldn’t before. The 12sx7 are a stand out and I was actually able to buy several pairs of TS round plate 12sn7 tubes for a reasonable price. |
My 6 month evaluation of the Cabernet is that I love it. Took me a while to sort things out but now my old preamp sounds downright harsh. I have found that tube selection makes a huge difference. I’ve also found that when I change tubes in the Cabernet I have to change tubes downstream too.
For example, the TS round plate 12sn7 sounds amazing as long as I use a tall 7n7 input tube in my amp (Inspire KT88 Firebottle) and use 6v6 outputs. If I just pop some 807 tubes into the amp it doesn’t sound very good until I change the input tube. If I use Raytheon 6f8g tubes in the Cabernet I can’t get sound I really like unless I put in e3375 tubes in the output. 12sx7 tubes in the Cabernet I really like an RCA 6sn7 in the input tube of the amp and 6ar6 tubes in the output. And on and on. Once I dial in the system it sounds amazing but every change requires changes elsewhere to get sound I like.
The switch that allows me to use both 6v and 12v tubes cost an extra $500. That gave me pause but I think it was worth it in the end. I have been able to get several pairs of TS round plate 12sn7 at reasonable prices. That probably evened out the price right there. On top of that I was able to get the so-called “bad boy” Sylvania tubes with little trouble. I can also use tubes that aren’t available as 6sn7 like the 12sx7 and the 14n7. The latter have extra support rods as compared tp the 7n7 and 6sn7. If you already have a good collection of 6sn7 tubes maybe the 12v switch won’t make sense for you but if you are starting out I recommend it. |
So either I am really stupid or the Cabernet has one of the most epic transformations with burn in ever. I have complained multiple times about how my Cabernet preamp couldn’t handle the 4v output of my DAC via its balanced inputs. Well, I tried it again all these months later on a whim and its fine.
All I can figure is that I was on the wrong input when I did my initial test. I have noticed that there is quite a bit of bleed between inputs. If you put as signal in on one input you can hear it if you select an other input. That obviously isn’t a big deal because you won’t be playing multiple inputs at the same time. But when I first hooked the Cabernet into my system I thought it was really quiet and very distorted. Then I tried a different input and it got MUCH louder. That’s how I knew I had been on the wrong input. The signal was still really compressed and distorted though. Did I really not try another input originally? I find that hard to believe but it is the most likely explanation. So yeah, the Cabernet is fine with higher input levels on the balanced connection. |
I posted in the tube rolling thread but it looks like this has more activity so ai'll post here too. I got my Cabernet about a month ago. When I ordered I had Mick add a switch that allows me to use either 6sn7 or 12sn7 tubes. The vintage 6sn7 tubes have gotten into the stratosphere while the best 12sn7 tubes are just sky high in price... It took some time for me to get a sound I really liked better than using a passive preamp. Initially the Cabernet really screwed up my system, it sounded terrible! Figured out my DAC was sending 4v via its balanced connection. Switched to RCA cables and got results more in line with what I was expecting. The general sound is bigger and lusher than with the passive. I'm not quite getting the detail but I think the tonal qualities make up for it. Plus the bass is amazing. So far I have cycled through a variety of tubes. Mick sent a pair of 12sx7 along with PSVane 6sn7. The 12sx7 are quite good and are a good benchmark to compare the other tubes. The "bad boy" Sylvania 12sn7 tubes seem to turn the vividness up and tightened up the bass. The round plate Tungsol tubes have lived up to their reputation as exquisite all rounders. They sound so... right. Can't put my finger on it but they sound different than the other but so satisfying. My most interesting tubes IMO are a pair of grey glass Sylvania 14n7 tubes. The 14n7 has the extra copper support rods like the super expensive metal based Sylvania 6sn7wgt. I have never heard of a sylvania grey glass 6sn7 before though. Anyway, these sound thicker, heavier. I could be happy with any of these really. They sound different but none of them sound bad. I'll eventually get around to trying the PSVane 6sn7, a variety of 7n7, and a few Sylvania 6sn7 tubes of various vintages. |
"Whats the benefit of doing the 12v?" Just the cost really. The price difference between 6sn7 and 12sn7 can be dramatic especially considering that they are the same tubes other than the heater voltage. The data between 12j5 and 6j5 probably isn't as stark. I don't think Tungsol ever made round pate 6j5 tubes but Sylvania made their most sought after tubes in single triode versions. Oh, and I suppose I enjoy rescuing abandoned tubes lol. I get a kick out of using tubes that would otherwise languish. |
I have been trying out a lot of different tubes in my Cabernet, ranging from RCA 12sx7, TS round plate, 6f8g from Sylvania and Raytheon, Sylvania "bad boys", 7n7, etc. My tube rolling mania got the better if me and I bought some adapters that allow me to use a pair of *j5 instead of a single *sn7. Got them from a guy in Bulgaria that does great work. Anyway, started with some Sylvania 12j5gt with round plates. Wow! There is a level of clarity and openness now that I hadn't heard before. Trawling through some forums it sounds like even the inexpensive metal version sound great. So if you'd like to try upping your tube rolling game without breaking the bank, try some 6j5 tubes! I also highly recommend getting Mick to install a 12v option on your preamp if you order one. It opens up a lot of possibilities. |
Well, I finally did it, I knew I would. I can switch between 6sn7 and 12sn7 on my Cabernet and I zapped some 6v tubes with 12v. Just wish it wasn’t my round plate Ken Rad 6f8g tubes! I left them on for several minutes like that before realizing what I had done. They are playing OK now but I assume I have taken years off of their life. SOB. Incidentally, what do you think would happen if I did the opposite? I’m assuming nothing but I don’t want to experiment
What would actually happen if I put a tube that is pin compatible with the 6sn7 but with very different characteristics into my Cabernet? Something like a 6sl7 or a 2c50. I only worry about damaging the preamp, don’t want to burn anything up. |
@hawkrising said:
I have come to love mine. I will say my initial impression was an overwhelmingly negative one. My DAC pushes out 4v over the balanced connection and that apparently overloads the input to the Cabernet. It made a terrible, compressed sound. Since that was my initial impression it really soured me on the device. I eventually figured that out and switched over to a single ended input which has the regular 2v output and things have been fine. The other thing I hated was that, compared to the passive section on my Ferya+, I could not get decent bass with the Cabernet in my system. No matter what tubes I tried the bass was just disappointing. running El38 tubes in my amp were especially impressive with the passive amp and just sounded lifeless with the Cabernet in the system. I'm not usually a big believer in burn in but it is the only explanation I can think of for the turnaround I heard. I now get the big, lush sound I was looking for along with solid bass. Although curiously I still can't get decent sound using the EL38 output tubes in my amp if I use the Cabernet. The clarity and frequency range I get from them with the passive is impressive. It all seems to go away when I use the Cabernet. Luckily I can use a wide variety of output tubes with my amp so I have several other combos that sound amazing. Makes me worry though if and when I get a more conventional amp that can only use a single kind of output tube. Anybody have any idea why the Cabernet might have such a bad impact with a specific amp output tube? |
I’ve been battling a noise issue. Adjusting the volume was incredibly scratchy and there was a background grittiness that was annoying me. Finally traced it to one of the 6l6gc regulator tubes. With cleaning I had managed to narrow down the noise to just one channel. Then when I swapped the signal tubes the noise was in the same channel. I never considered the regulator tubes because I never touched them. The preamp came with them already installed and I never used a different tube. Anyway, I took out the one on the right, cleaned the pins and now there’s no more noise! I wonder why that tube got noisy, very strange. |
I didn't have any "upgrades" done to my Cabernet but I did have a few mods. I have two balanced sets of outputs. The bigger one is that I can run either 6sn7 or 12sn7 in my amp. That cost me $500 but considering what the better 6sn7 tubes cost and how much less the identical 12sn7 I think I made the right decision.
Others have decided to use a pair of 6j5 per side instead of 6sn7. That would also be an effective way of getting great tubes at a much lower cost. I prefer getting the 6sn7 sockets though. I can use a 6sn7 to 2x6j5 adapter if I wanted to. |
When I asked about a copper Cabernet last year Mick said he wasn’t offering those anymore because the scratch too easily.
When you order remember that you can customize the preamp. It’s one of the advantages of a made to order item. I opted for a 6v/12v switch and an extra set of balanced outputs. I see someone else had theirs made to accept 8sn7 tubes. Others have decided to use 6j5 tubes instead. 6sn7 tubes have gotten so expensive it might be worthwhile to explore other options. |
I think it’s fair to say that Mick considers those more tweaks than anything else. I also understand his reasoning behind not wanting to change the sound of his product. He knows and understands how his products sound. When you make things sound different he doesn’t know what the end result will be. And to be fair, you don’t either! Lol. Once you get a feel for the sound you can always tweak it later on
When I talk about customizing I’m talking about functional differences as opposed to circuit or design changes. Appearance, tube voltages, outputs, inputs, etc. |
@tksteingraber I have put many tubes through my Cabernet. Keep in mind that sounds good will vary depending on what tubes I have in mt amp. When Mick built mine I had him put in a 6v/12v switch. Best thing I ever did. 12sn7 are much less expensive4.
Raytheon 6f8g T plates Sylvania tall plate 14n7. They aren’t the same as the 7n7! GEC/Osram/Marconi b36 Ken Rad round plate 6f8g Interestingly, to me at least, is that I haven’t really liked having the Sylvania so called bad boys or Tungsol black glass, round plate in my Cabernet. And, yes, they are actual bad boys with the right dates, construction etc. I do like the Tungsol BGRP as drivers in my push pull amp.
I have also had a lot of luck with single triodes with the use of adapters. Mick makes his Grange with 6j5. The 6/12j5 and equivalents, while rising in price quickly, are still good deals compared to the 6sn7 market. Here are some of my favorites: Radiotron (from Australia) 6j5gt Raytheon 12j5wgt National Union JAN 12j5gt Cossor branded 6c5g. There’s some debate who actually made these but they aren’t the GEC. Currently available from Langrex. GEC l63gt brown base. Fun fact, the 6c5 is a good substitute for the 6j5 and I got Mick’s blessing to use them in the Cabernet. The 6c5 is actually, literally, a 6j7 triode wired so it is possible to use that configuration with the appropriate adapters as well. Haven’t done that yet but I will soon. |
Heh, just realized all of the ones I mentioned need adapters lol. These should be pretty close to the same tubes if you get the 6sn7 versions but the prices will make you cry:)
GEC/Marconi/Osram b63 Raytheon VT231 Sylvania 6sn7wgt I’m not sure if there is an equivalent 6sn7 to the round plate Ken Rad… My advice is don’t be afraid of adapters, especially if you want access to the best sounding tubes at a reasonable cost. 10-15 years ago you could buy any tube you wanted even if some were more expensive than others. Now some of the best tubes are difficult to find and are incredibly expensive when you do find them. I think the NOS tube rolling game has just about run its course, at least for the generally accepted “best” versions. You can still get great single triodes. A 6j5 is just a half of a 6sn7 so two of them are exactly the same electrically. Mick would be happy to make a preamp with 2x 6j5 instead of 6sn7 if you don’t want to use adapters. Or do what I did and get the option to use 12v tubes *and* use adapters:) |
