Thanks! Appreciate your insight and link. I did check out that Audiogon thread before but I’ll cruise it again more thoroughly now that I actually bought it. I did just pick up a Melz 1578 for my Mogwai SE headphone amp, but not sure if it’s one of the ‘good’ ones or not. I believe it’s a legit 1578 with a rectangular getter, but it doesn’t have the holed plates.
At any rate, once I get the Supratek up and running I’ll take my time wading through the massive amount of 6SN7 information online. I’m looking for more of a clean sound, so probably more neutral sounding 6SN7s and/or 5881s.
It will be strictly in a headphone chain for now. In front of either a Pass HPA-1 or Mogwai SE rev 2. Hopefully it sounds good with at least one of those amps.
a. The plates are perforated with 5 holes.
b. The micas are rectangular (not oval) with a ledge on both ends.
c. The support rods are stainless steel with long rectangular metal support brackets at the top.
This picture gets pass around a lot in the Internet and I found this one really helpful:
Funny enough that image of the different versions was in the ad for the tube I bought. I think he wanted to point out the steel brackets and the rectangular plate mica, which the one I bought has. No holes though. It was cheap(ish) so it might not be ‘the one’. Assume a Melz but not sure where it falls. Maybe just a smooth plate version
That’s really cool, I didn’t know a version like that existed. It’s probably still a Melz, so it should be close sounding enough. If it sounds great on your current tube amp, I’m sure it will sound great on the Supratek.
Would love to hear your thoughts once you get the Melz into your Cabernet and how they sound. I just recently even found out about the Melz so I’m a bit intrigued. But also plan on pursuing other 6SN7 options for the Chardonnay. That’s the fun!
Directly copied from What’s Best Forum, I have personally had excellent results with the Meltz 1578 used in my Lampi B3.
“As the background of the Melz 1578 tube is somewhat mysterious, unsurprising given its cold war soviet background which predates many of us, I thought I would share what I have learnt.
The Melz 6h8c is analogous to the US 6sn7 tube and was designed for audio use. Its cousin the 1578 was designed for use in demanding industry applications, most interestingly the Soviet nuclear industry to pass a 1578 signal, whatever that is.
Both versions share a similar appearance and both are labelled 6h8c. Some production runs of the 1578 were also labelled ‘1578’, though not all. Conversely, the ‘1578’ label has been added to the regular 6h8c to trick buyers into paying a premium price. My advice is to disregard it and focus in the internal construction.
The 6h8c tubes also used metal bases and drilled holes in the plates in their earlier production runs, which can confuse people into thinking they are 1578. There are however two internal construction differences unique to 1578 which will identify them
the lower mica (below plates) is rectangular in 1578 but oval in 6h8c
the upper mica supports (above plates) are large bent silver metal in 1578 but small straight opaque synthetic in 6h8c
I have only ever used the 1578 and not the 6h8c, so I can’t comment on the sonic differences but have read that 1578 is superior. The early production 6h8c might still be quite respectable however don’t be tempted into overpaying for them.”
Yep, it looks like with the Melz 1578 tube, you reallly got to look at the internals with that tube. I heard there is a soldering problem as well with a lot of the early production of those tubes, so you got to look at that as well.
Yes, I did see that WBF write up as well. It seems like the above couple bullet points are the keys. Once you know what to look for, it’s easy to distinguish between the different variations. The easiest thing to look for are the metal brackets at the top.
The tube I bought had everything but the holes in the plates. I did read a comment in the head-fi 6SN7 thread from someone who heard what seemed to be my version (smooth grey plates) and wasn’t overly impressed. So I guess I’ll see! Hopefully will have it next week
Don’t pay mind to what 1 individual stated, unfortunately it will color your opinion so try and listen to it in YOUR equipment and simply judge for yourself. Part of the problem in this hobby is that we read opinions on the internet, many many opinions and those words will color views of individuals without them even realizing. Agreed, this particular tube you have is a bit of an unknown. Wait try it for a good long while and see if YOU enjoy it. Happy Listening
In addition to ensuring you don’t suffer impedance mismatch such as something outside the ratio of 10:1, another factor to consider in the specs is how much gain the pre-amp will provide as part of its function. You will often see different gain ratings for single-ended output on the pre-amp. This is important as it provide , in combination with the overall gain of the power amp, an aggregate gain rating which is is just as important as input impedance.
An example, if your pre-amp gain is only say 12,5 dB, power amp is 11.5 dB, total combined is 23.5 dB, about 10dB short of the sweet spot. No I did not pull these numbers out of my ass, it’s based on an actual pre-amp and power amp combos which sound like
Granted this scenario is also exposing some weakness of the different components more so, however the fact remains it’s a factor which needs to be considered for matching up along with the input impedance of a power amp first, followed by output impedance of the preamp second.
Do you have the statement about input mistakem for what was said about output?
Input into pre-amp should not care if it’s SE or Balamced, it will read rhem as they are. On the out, that is wheee you should be noticing a difference, the very least a slightly louder gain due tot balanced signal running hotter. It’s the Supratek a single ended pre-amp, or a fully differential pre-amp/
Yep. The class D amp that is currently getting build have a gain of 19.05. The Supratek Cabernet DHT is a high gain preamp, but it also has customizable gain where I can lower the gain from a knob. I never played with that function yet as all the amp I had didn’t really need me lowering it.
Yeah, I found that weird as well. I was reading Mick old blog on his thought on preamps requirement. He talked about how he didn’t like tube preamps having XLR input, but he probably changed his mind later in life because the Supratek Cabernet DHT contain XLR input. What i stated in the previous post is what Mick told me. XLR input slightly different from RCA, but XLR output the same as RCA output.
I was hoping Mick says RCA is the way to go, because I had been eyeing a certain RCA cable, but it looks like I will still remain full XLR balance in my speaker system because I like the Mystique Evo DAC more using XLR for more power and my soon to be power amp is a balanced only connection.
I spoke with Johnny (US repair guy) about that last year regarding what kind of design it is. He told my Supratek is a single ended design and he had the same answer as Mick at least on the XLR/RCA output that they performed the same as an exception that if I only wanted to use just the 6SN7 tubes and not the DHT tubes, I will still use that dedicated RCA output for it.
I also did experimented last year if the Supratek would benefit from full balanced connection on the Allnic HPA-5000XL, so I got (2) set Audience OHNO XLR cables and compare it to a RCA cable and the level of volume seem to be the same. Then I switch from XLR input to RCA input and the volume level did change.I then later sold the other pair of Audience OHNO XLR cable because I thought my next power amp move will be RCA input and now I am kicking myself for selling it…
That’s typical of tube based transformer coupled amps, XLR in requires an additional transformer, XLR out is the same as RCA out beccause the out put transformer provides isolation, and it’s just a question of if ground is on the - pin or center pin. That can be done with either an extra transformer tap or a pair of resistors.
The biggest issue with matching power and pre amps is usually input sensitivity of the power amp, pre amps are often very hot ouputs, and input sensitivity is often lower than you might think. It doesn’t really affect very much because you can just turn the volume down on the preamp, but the mismatch can be so bad that you have little to no range on the pre volume dial.
Outside of that it’s hard to tell, very few dedicated pre amps have high enough output impedance to cause problems, most power amps are at least 10K input impedance, often MUCH more than that. SS will generally be lower, than tube amps.
I’ve been having a lot of fun tube rolling the Supratek, it kinda made me want to get a power tube amp just to tube roll for the sake of tube rolling. I’ve been breaking a lot of my own rules because I wanted to at least spend $4K first and finish room treatment before spending anything else, but tube rolling have been really fun doing lol. The Melz is my last tube of the year besides when my new Rectifier comes in maybe mid June or early July. My biggest worry is that I have been watching some reviews on any good synergy with some tube amps. Some people found success with built in preamp on their solid state DAC vs using tube preamp when pairing some tube power amp. A lot of of Supratek owners seem to use their Supratek tube preamp with a solid state amp. I do like using the Allnic HPA-5000XL a lot with the Supratek preamp, but I don’t know if that is a one off kinda of thing.
That’s true, I notice that when looking up some tube power amp input impedance. I was looking at the Allnic tube preamps and a lot of them are around the Supratek output impedance. One of the tube power amp I have on my wishlist which is a Dynaco ST-70 is said to have 470K input impedance, so it was a relief knowing I don’t have to worry about that.
The designer pretty much picks the input impedance on a tube power amp, the tubes them selves have impedances in the Megaohm’s.
My 2c, and I went through this decades ago, so take it with a bucket of salt, good active pre’s are well worth it, there is a purist argument for passive pre’s but in practice it doesn’t hold up.
There are a few reasons for this.
Having said that the key word is “good” active pre, and IME that gets expensive.
There is also a huge synergy component between power and pre amp, and IME it’s a bit of a roll of the dice, and it’s not easily determined by specs.
I still don’t know really know what good synergy means tbh or if I know if I found it yet besides one recent combo I really like. I don’t know if things sound good and that’s good synergy or when things starts sounding really really good is good synergy.
I watch this video from Thomas & Stereo and it helped me understand it a bit more on finding good synergy. It’s been a while since I watch this video, but I think I remember him talking about pretty similar in what you said where finding synergy is basically luck. Finding good specs and knowing what it sounds like and putting it together helps, but it really ultimately comes down to luck on how well it synergize together.
I feel like I want to say 1 really special synergy that I’ve been really liking recently is the Sennheiser HD580 Jubilee with the old school RCA tube set in the Supratek preamp while being power by the Allnic HPA-5000XL. The complete old school RCA tonality mix with the Sennheiser HD580 Jubilee sounded absolutely magical. Then I swap the RCA VT-231 with the Melz 1578 tubes. It gave me very good clarity and overall made my system sounded much cleaner which I really like with the Mysphere 3.2, but it loses that magic with the Sennheiser HD580 Jubilee. I want to call the HD580 Jubilee with the complete RCA tube setup synergy just because it felt truly special vs I always think the Mysphere 3.2 and Platimon VC1 speaker to always sounded really good and the recent tube changes just elevate it to the next level.
I had the Melz 1578 in this audio chain: Server/Streamer > Mystique Evo B4B 21 DAC > (RCA Anticables) Supratek Cabernet DHT Custom 45/6SN7 Preamp (2) RCA Radiotron UX-245 Tube, (2) Melz 1578 Tube, (2) RCA 6L6GC Tube, and (1) RCA 5U4G Tube > (XLR Audience Ohno) Allnic HPA-5000XL > Headphones
In my Supratek, the Melz 1578 is clearer/cleaner sounding all around compared to the RCA VT-231. I say the Melz tube made my system a bit brighter and made my system less warm at first. But I feel like a couple of days later that bright feeling went away. I am not too sure if my brain adjusted to it or if the tube sound changed over time, but it sounds balanced to my ears currently.
I do miss the RCA VT-231’s warmth and lushness from time to time, but I do enjoy the Melz tube more on modern-day recording vs whereas I enjoyed the RCA VT-232 more on older recordings. The Melz tube lifted the touch of veil and made the mids a bit more transparent, but in return loses that old-school RCA tone that I really like when using a headphone like the Sennheiser HD580 Jubilee.
The Melz tube felt more of a proper match with my Mysphere 3.2 where I get more of that nice clear transparent mids. I say the Melz 1578 tubes upped the level of clarity and resolution of my system overall. Mids are still very enjoyable and organic sounding, it’s just not as rich sounding as the RCA VT-231. I say I probably prefer almost all my headphone collection using the Melz 1578 tubes over the RCA VT-231 because of the up in clarity and clean sound in my system with the exception of the Sennheiser HD580 Jubilee when paired with the Melz 1578 tube sounds a tad more neutral sounding vs when paired with the RCA VT-231 when it sounded a little more warm and fun.
If you are looking for something to elevate your system’s midrange clarity and want a more “clean” sound in your system, the Melz 1578 will do the trick in the Supratek Cabneret DHT. If you want more warmth in your music with a little more classic RCA tone in your system, the RCA VT-231 sounded excellent with the Supratek Cabernet DHT.
For my system and current goal, I would like to maximize midrange clarity while maintaining a musical sound in my system. I will probably stick with the Melz 1578 combo with the RCA UX-245 on the Supratek to see how it goes with the Platimon VC 1 speaker system.
The last thing I will swap out in the Supratek Cabbernet DHT for at least the rest of the year is the rectifier tube. I think after that, it should hopefully kill my mood on tube rolling and I can focus on maximizing other parts of my system.
A peanut butter and jelly sandwich, great synergy.
A Nutella and jelly sandwich, not great synergy.
A Nutella and marshmallow fluff, great synergy.
The entire thing can be summed up in the phrase, the whole is more than the sum of its parts. Synergy is when something magical happens, not just sounding good, but sounding like it shouldn’t be THIS good.
That’s a pretty good analogy and I like that comparison a lot. Peanut butter by itself to me ain’t nothing worth talking about by itself. Jelly is pretty good. Combining peanut butter and jelly gets more interesting. Then you add 2 slice of bread in the mix and now it turned into a childhood classic. Idk if I took that analogy the wrong way, but finding good synergy takes an open mind and some luck.
I should also try to keep some equipment more often as well just to play with pairing more, but storage is going to be an issue. I feel like finding a good synergy with headphone seems easier since you carry headphone and travel to shows and meets to try different pairing. Finding a good synergy with speakers becomes more pain in the butt since the room itself is now a factor and finding the right speaker placement is also a thing. It’s also harder to just bring your own speakers to plug in audio shows to test their amp, so I just gotta buy different pairing and see what happens.
For speaker synergy, that’s when I started heavily relying more on reviewers opinion just because they do have access to multiple equipment. I just also got to keep in mind their room and taste in music is different from mine. I tried one reviewer “dream combo” of the Platimon VC 1 and orchard audio amp and it did sounded much more amazing than I expected. It’s actually my current favorite combo, so there’s that. I think I want to try another reviewers “dream combo” of the Brunoco Terra integrated tube amp and the Platimon VC 1 in the future just because I became more of a fan of old school RCA sound recently. But that’s just more of a thought than something I actually want to do since I am prioritizing the fund on something else in chain rather than another amp.
