LampizatOr Horizon - Tube Rolling Paradise

I continue to listen to various tubes in my Horizon and came upon this post which I found highly illuminating.
No recommendations to make based on this, but I learned a lot from this post (differences and rationale for direct vs indirect heater rectifiers, why I like GZ 34's (lower voltage drop), and other oddities that are mostly meaningless!
No need to look at this unless you are a real dork o_O

Needless to say, I had to have a look, LOL!
 
  • Like
Reactions: marty
I continue to listen to various tubes in my Horizon and came upon this post which I found highly illuminating.
No recommendations to make based on this, but I learned a lot from this post (differences and rationale for direct vs indirect heater rectifiers, why I like GZ 34's (lower voltage drop), and other oddities that are mostly meaningless!
No need to look at this unless you are a real dork o_O

Thanks a lot, Marty.
VERY interesting!
 
I did. IMO and in my system, there is no comparison.The TS KT 170 takes my system far beyond what I heard with the KT88. In fact my KT 88 will soon be for sale.I also have Genalex KT 77 which also didn't pass muster with respect to the KT 170.But again I believe all of these vary from system to system. I looked for the best sound in my system which was the KT 170 rather than the KT 88
Hopefully the KT 170s are more reliable than the KT 150s, which have such poor reliability that I heard many well-known tube vendors are reluctant to carry them. Kent McCollum, the Quad expert who restored my 2905s, said he’s stopping buying the 150 tubes due to very poor QC at the Russian factory. I don’t know if that’s a recent problem due to the sanctions.

This is a primary reason I decided against going to the Horizon. It’s very hard to find pentode tubes that can match the reliability of 300B tubes, for example. As it is, I’m too invested in ARC gear that heavily uses 6H30P tubes and KT120 tubes. I have ample supplies of both, and fortunately the 120s seem reasonably reliable. But mostly my ARC gear sits idle now. Eventually I’ll sell it all to divest myself of any dependence on these tubes.
 
Hopefully the KT 170s are more reliable than the KT 150s, which have such poor reliability that I heard many well-known tube vendors are reluctant to carry them. Kent McCollum, the Quad expert who restored my 2905s, said he’s stopping buying the 150 tubes due to very poor QC at the Russian factory. I don’t know if that’s a recent problem due to the sanctions.

This is a primary reason I decided against going to the Horizon. It’s very hard to find pentode tubes that can match the reliability of 300B tubes, for example. As it is, I’m too invested in ARC gear that heavily uses 6H30P tubes and KT120 tubes. I have ample supplies of both, and fortunately the 120s seem reasonably reliable. But mostly my ARC gear sits idle now. Eventually I’ll sell it all to divest myself of any dependence on these tubes.

I lot of Horizon owners are using KT170s and I have yet to hear of issues. Not a huge sample size but still noteworthy.

Regarding the reliability of 300Bs I have heard of issues with them here and there. All tube types can have problems.

Like the Pacific, there are numerous options for the “power” tube. I am using EL51s right now.
 
I’m surprised that this thread appears to be running out of steam at a time when more and more Horizons are being delivered, which means folks are now getting more time to become familiar with the numerous tube choices for their units. I therefore thought I’d provide an update on my tube preferences and the rationale for their use.

The British are coming, The British are coming.......The British are here!

TRIODES

I might as well start with the most controversial choice, the legendary Tung-Sol Black Glass Round Plates (BGRP). This tube has an ambivalent following. I was curious to learn whether it is the highly revered tube that many have praised, or whether it is a tube that deserved some of the pans such as those by the well-known 6SN7 user and reviewer Robert Hutton from a few decades ago. In my view, the truth lies somewhere in between, but is mostly favorable. It is certainly an excellent tube with an interesting story. According to Hutton, the tube became enormously popular many years ago when Upscale Audio touted them heavily, which caused their prices to escalate dramatically, until Upscale ran out of inventory, at which time they dropped them like a hot potato and moved on to something else leaving only their high price in its wake (which Hutton thought was entirely undeserved.) More damning perhaps is that Hutton thought the tube was somewhat sibilant sounding on top hence he became a very vocal naysayer. While I can understand Hutton’s concern about the sibilance issue (easily demonstrated on Patricia Barber’s wonderful cover of “The In Crowd”) it is a relatively minor misgiving that doesn’t detract from the tubes wonderful assets which most prominently is a very beautiful midrange. Although I enjoyed this tube, it has not become my triode of choice for two reasons. The first is that the bass, while well defined, is rather polite. Having just returned from Carnegie 2 nights ago hearing Scheherazade and some assorted Victor-Lobos pieces, it is the 40-80Hz range of the tube that just plays too light for me in my system. The main liability of this was the sonority of lower brass, which for me, just doesn’t provide the correct “weight” of the orchestra that is more like the real thing. Secondly, the entire treble range while good, doesn’t have the definition and clarity of some other triodes in this range such as the Sylvania 6SN7W/B65 or the fabulous Mullard ECC32/31. In short, the BGRP, while very good, just didn’t have any magic for me to the point that it was a keeper. I ended up selling mine a while ago. But that midrange is truly gorgeous.

Almost but perhaps not quite as controversial as the TS BGRP is the Sylvania metal base B65. Most who have heard this tube are impressed with the top end for good reason. It’s performance there is exceptional. There are parts of the frequency spectrum that are so extraordinary, it translates to genuine impressions of being fooled by thinking you are hearing the real thing. This is the magic that everyone comments on when hearing these beauties. The tube is just outstanding down through the midrange and lower. It’s liability, which is just to say that it is not a perfect tube, lies in the bass range, particularly in definition more so than extension. There, it’s good, but not great. Having tried a number of Sylvania 6SN7’s I can relate to dminches when he says the bass on Sylvania’s are like Forrest Gump’s box of chocolates- you never know what you’re going to get! I agree. For example, I found the bass on the VT 231 6SN7 GT to be very big and almost overwhelming, while the 6SN7W black base had noticeably atrophic bass. Still, I found that if you mate the B65 with a compatible rectifier with strong bass, the combination can be thrilling. There is just so much that the B65 does exceptionally well that virtually no other tube does, which is why it always turns up in the top echelon of 6SN7’s by audiophiles. It may have some minor weakness in the bass, but I’ll share it is a tube I will never sell. It’s a reference tube in so many ways because it’s more than a great tube for listening to music. Rather, it’s a great tool for comparing other tubes to in order to assess their performance to see what they bring to the table.

Finally, there is the Mullard ECC32/31. I might as well just say it. This tube is simply beautiful. It does the entire frequency range so well and is so musically balanced that it just stands out among its peers. The articulation, frequency response, tonality and sense of “rightness” is exceptional and most importantly, delivers that one thing that we all aspire to, which is listening to music while letting the gear or component get out of the way. With the Mullard, that is what it does extraordinarily well. You just don’t think about what the tube is doing. You just end up listening to music. This tube has genuine magic, but here it is almost everywhere not just primarily in one frequency range. But if you want to start with accolades somewhere you might as well start with the midrange, which is stunningly good, low in distortion and harmonically rich. The top end is very pure and sonically wonderful. It would be a fool’s errand to try and compare it’s top end to the Sylvania B65. They are both excellent yet but different (but each is a light year better defined for me than the TS BGRP). The bass is also very well defined, well extended and has the right balance which renders the orchestra floor very believable to me.

It should be mentioned that while the ECC32 is very expensive (even if you don’t buy from the whore in Hanoi), there is a far more accessible alternative which is the ECC31. As has been mentioned a few times here the ECC31 is identical to the ECC32 but it has a common cathode grid and therefore requires an inexpensive adapter (eBay) to use in the Horizon. Both have Lukasz' approval which is very important since the ECC32/31 is not considered a drop in plug and play for a 6SN7.The Mullards have 50% higher current draw and grid voltage, gain and transconductance are all different than a 6SN7. Again, Lukasz assured me that the Horizon is very over-engineered so the Mullards are easily handled in the Horizon. While ECC2’s can go for over 2K/pair, the ECC31’s are generally a few hundred bucks per tube if you shop wisely. In fact, there was a new in box Mullard ECC31 advertised recently for $75 which just drove me nuts as I would have bought it in a heartbeat if a pair were available.

PENTODES

As many have discovered, it's best to think of the 3 individual tube types not only individually but as cast members of a larger sonic consortium. Regarding pentodes, nothing has given me the same sonic enjoyment as the Mullard EL34 xF2 made in Blackburn. The main attribute of the Mullards, which is why they are so revered, is not only their sonic beauty but their resistance to overload. This is true whether its solo piano gone Yuja Wang berserk or Mahler in Warp 9 overdrive. In the history of high end audio it may not be hyperbole to say the Mullard EL-34 may be one of, if not the most consistently praised tube ever made. It's popularity waned a few decades ago when massive wattage tube power amps were made which utilized the greater power available of 6550 or KT88 valves. But bigger doesn't necessarily mean better and in the case of the Horizon, power is not the primary consideration for Lukasz's unique hybrid octal design as it might be in a full blown powered amplifier. Some reviewers have simply said that the key feature of NOS Mullard EL34's is that they just sound more like music than any other equivalent pentode.. I would agree and for that reason, it’s my keeper. I sold my KT-170’s a while ago. One advantage of the KT-170’s however, is that they are very obtainable and that’s worth great deal as the Mullards are not a dime a dozen. It also doesn’t hurt that the KT-170’s sound very good so they are a very solid choice. I could easily live with them, but for me, the Xf2’s are in a different league and bring another small level of sonic truth. Piano, voice and strings are exceptional and simple tracks of these can be used to easily hear the merits of this tube. I read an old comment on another blog where one listener said that after listening to a piano on the Mullards, it wasn't worth hearing a piano on any other tube. A bit of an exaggeration perhaps but I understand why he made that comment. They aren’t cheap, but they’re generally obtainable for about $250-300/tube, which considering the price of the Horizon, seems like a modest investment to me.

RECTIFIER

Previously, I wrote that the Takatsuki 274B was my rectifier of choice for the Horizon (and the GG2). Post #2845
https://www.whatsbestforum.com/thre...ling-review-thread.26478/page-143#post-819130

However, I voiced a minor concern that as good as it is, it is a somewhat dark sounding tube (“bottom-up” or “yin” sounding). Yet its strengths are so good, particularly in the bass through upper bass, that it remained my recti of choice. Until now. The reason for exploriong my new recti reference was the comment I made previously regarding my sense that a Steinway piano recording sounded a bit like a somewhat darker Bosendorfer through the Tak and this remained a legitimate concern. What put me over the top in re-opening the rectifier exploration was the uncanny midrange of the Mullard ECC32. The Mullard, combined with the Tak was just not able to nail Steinway Grand with openness the way I had hoped due to some aforementioned darkness. Enter the incredible MOV/GEC U52. This rectifier is no secret.

To be continued...
 
Last edited:
Part 2

In DubStep Girl’s massive rectifier review, there is no shortage of accolades for this rectifier so its worth lifting it (with full acknowledgment) in its entirety from Post #1 of this monster thread.

https://www.head-fi.org/threads/dub...mparison-rectifer-tube-rolling-thread.694525/

“British tube made by GEC/MWT/Marconi/Osram, etc. I've also seen it branded under Mullard or Brimar. It should be compatible with most 5U4G amps. Mine has grey plates but I've also seen black plates as well as black base versions of this tube. Compared to the Western Electric 422A, I think this would be the second best rectifier tube available. Performance is almost the same as the Western Electric 422A, perhaps only being a little warmer and having a more euphonic tone/timbre/decay. However, it maintains its speed, transparency, layering, soundstage, and imaging. Like the WE422A, it's pretty much nearly perfect in every way and maintains a sort of neutrality throughout. Warm tube sound but with extended air and treble, great staging, deep bass extension, very nice texture and decay as well. Absolutely zero grain with this tube, just like the WE422A, one of the best tubes out there! Sound-wise, it's very similar and shares the same British tone and sound signature of the GEC 6AS7G power tubes. Just like the WE422A, this tube can really bring you to tears on the right music, so much magic in the sound of legendary tubes. Price is slightly cheaper than the 422A but similarly priced with tubes going for $350-500$ a piece.”

With the U52, the sound of any good Steinway recording has alas returned from a slightly darker sounding piano to the openness and clarity that is synonymous with the sound of Steinway D! In fact, this clarity is apparent not just in a piano but in everything from human voice right up through the violins to the air of the hall. Oh yeah, the U52 is about 1/3rd of the cost of the $1200 Tak, so that's a huge plus as well. Cost aside, the U52/ECC32 combo is utterly authentic sounding to the sound of instruments I hear in the hall or club which its why they're keepers for me.

Recall I mentioned I will likely never sell my Sylvania B65’s even though the Mullard ECC32 is my triode of choice. Well, I would make the same comment for the Takatsuki. I won’t part with it because it still amazes me with what it offers in the integrity of its low through upper bass. So it’s a reference worth inserting from time to time if for no other reason than just to check one’s sanity and system gestalt when playing with things such as cables, fuses and other assorted audio gear or accessories.

So that’s the update in a nutshell. In summary, I’ve gone all British with Mullard EL-34 pentodes, Mullard ECC32/31 triodes and a MOV/GEC U52 rectifier. It’s the combo that work’s very nicely together in my system. It’s hard to believe I can actually say I have no plans to change any more damn Horizon tubes in the foreseeable future, but that’s where I am at the moment.
 
Last edited:
Marty, thanks for the write up. It has been a while since I have tried anything other than the EL51s/TS 6SN7s/Tak 274B due to rolling fatigue.

I will give my ECC32s another listen. I don’t have EL34s or XF2s to try. May have to get a quad one of these days.

I do have a U52 and WE 422A. Those are easy to roll in.
 
  • Like
Reactions: christoph
Hmm.. perhaps in the next model that lies beyond the Horizon, Lampi can expand the possibilities from tube rolling to other areas. Some suggestions:

1. Power supply rolling: The Chord Dave forum is chock full of folks rolling external power supplies for the Dave DAC (e.g, Sean Adams’ ARC6 supply), which ends up costing more than the Dave. Naim has a huge slew of external power supplies for their products. For instance, their ND 555 streamer/DAC requires one pricey external power supply, but you can add another one as well. Again, the cost of two LPS’es can exceed the DAC price. I’m surprised given the price, Lampi did not provision an external LPS for the Horizon.

2. Resistor/capacitor choices: Lampi can let you choose other resistors and capacitors. People can swap stories about changing Vishay resistors and Mundorf capacitors.

3. DAC chips: make the chips user replaceable. You can endlessly roll DAC chips as they come on to market.

4. Software rolling: change the software for upsampling or filtering. A lot of DAC makers already allow you to do this.
 
I understand rolling fatigue! It's very real!! No matter when I see another tube again, it will be too soon !!
David, I'd love to learn your thoughts on the legendary 422A. Too rare and too expensive to consider for me, especially If one wants to buy a back-up if you fall in love with it. But I am curious to hear what folks think of this thing in a Horizon. I guess we're all waiting for WE to remake their 274B so why spend a fortune on an unobtainable tube that's as rare as hen's teeth and costs a small fortune?
 
Last edited:
  • Like
Reactions: christoph
I understand rolling fatigue! It's very real!! No matter when I see another tube again, it will be too soon !!
David, I'd love to learn your thoughts on the legendary 422A. Too rare and too expensive to consider for me, especially of one wants to buy a back-up if you fall in love with it. But I am curious to hear what folks think of this thing in a Horizon. I guess we're all waiting for WE to remake their 274B so why spend a fortune on an unobtainable tube that's as rare as hen's teeth and costs a small fortune?

I will let you now. I know that I didn’t really like it in the Pacific. I found it to be bass light.
 
  • Like
Reactions: christoph
I will let you now. I know that I didn’t really like it in the Pacific. I found it to be bass light.
Can I tap the collective wisdom? With regards to tube matching for the Horizon in particular, how important is it for the pentodes and the dual triodes? Which parameters are relevant and what percentage tolerance is defined as ‘matched’?
 
Part 2

In DubStep Girl’s massive rectifier review, there is no shortage of accolades for this rectifier so its worth lifting it (with full acknowledgment) in its entirety from Post #1 of this monster thread.

https://www.head-fi.org/threads/dub...mparison-rectifer-tube-rolling-thread.694525/

“British tube made by GEC/MWT/Marconi/Osram, etc. I've also seen it branded under Mullard or Brimar. It should be compatible with most 5U4G amps. Mine has grey plates but I've also seen black plates as well as black base versions of this tube. Compared to the Western Electric 422A, I think this would be the second best rectifier tube available. Performance is almost the same as the Western Electric 422A, perhaps only being a little warmer and having a more euphonic tone/timbre/decay. However, it maintains its speed, transparency, layering, soundstage, and imaging. Like the WE422A, it's pretty much nearly perfect in every way and maintains a sort of neutrality throughout. Warm tube sound but with extended air and treble, great staging, deep bass extension, very nice texture and decay as well. Absolutely zero grain with this tube, just like the WE422A, one of the best tubes out there! Sound-wise, it's very similar and shares the same British tone and sound signature of the GEC 6AS7G power tubes. Just like the WE422A, this tube can really bring you to tears on the right music, so much magic in the sound of legendary tubes. Price is slightly cheaper than the 422A but similarly priced with tubes going for $350-500$ a piece.”

With the U52, the sound of the Steinway has alas returned from a slightly darker sounding piano to the openness and clarity that is synonymous with the sound of Steinway D! In fact, this clarity is apparent not just in a piano but in everything from human voice right up through the violins to the air of the hall. Oh yeah, the U52 is about 1/3rd of the cost of the $1200 Tak, so that's a huge plus as well. Cost aside, the U52/ECC32 combo is utterly authentic sounding to the sound of instruments I hear in the hall or club which its why they're keepers for me.

Recall I mentioned I will likely never sell my Sylvania B65’s even though the Mullard ECC32 is my triode of choice. Well, I would make the same comment for the Takatsuki. I won’t part with it because it still amazes me with what it offers in the integrity of its low through upper bass. So it’s a reference worth inserting from time to time if for no other reason than just to check one’s sanity and system gestalt when playing with things such as cables, fuses and other assorted audio gear or accessories.

So that’s the update in a nutshell. In summary, I’ve gone all British with Mullard EL-34 pentodes, Mullard ECC32/31 triodes and a MOV/GEC U52 rectifier. It’s the combo that work’s very nicely together in my system. It’s hard to believe I can actually say I have no plans to change any more damn Horizon tubes in the foreseeable future, but that’s where I am at the moment.
Marty thanks as always on the extensive “report” filled with details. As we’ve been in contact regurarly I knew your opinion and can second from my side all what you wrote regarding triodes as i have all those tubes (minus Sylvania). Rectifier wise still i need to try U52 when i pull it out of basement but Taka as such is not my cup of tea exactly from the same reason you stated. Pentodes wise i have bunch of different ones which i tried including el156 and f2a (love them both) but my favorite is a tube which i will not disclose until i get a second quad as in general you know how much we struggled to get our quads.
Your input is as always much appreciated!
 
I understand rolling fatigue! It's very real!! No matter when I see another tube again, it will be too soon !!
David, I'd love to learn your thoughts on the legendary 422A. Too rare and too expensive to consider for me, especially If one wants to buy a back-up if you fall in love with it. But I am curious to hear what folks think of this thing in a Horizon. I guess we're all waiting for WE to remake their 274B so why spend a fortune on an unobtainable tube that's as rare as hen's teeth and costs a small fortune?
Wow Marty, thank you so much for the wealth of information on the full compliment of tube types in the Horizon. I’m fortunate enough to have a couple of backups of WE 422A’s since I use them in my SET monos. In fact it was the first rectifier I rolled into my Horizon before I got the Takatsuki 274B.

I’d pretty much settled on the tube complement that Steve is using and David’s recommendation of the Tungsol BGRP’s. So I snatched up two pair of NOS Tungsol BGRP’s when they were more available(figured I’d have a backup pair but ended up using them with adapters as the input tubes in my SET’s).

I think the dilemma with settling on tubes early on is that we all didn’t know how long the actual break in time would be for the Horizon, And for me, I was also waiting on my Taiko Extreme and then had to wait for it to break in, not to mention now having the XDMS alpha as a new variable.

Anyway Marty, you inspired me to swap out the Takatsuki 274B with the WE 422A for a long evening of listening with a familiar compliment of albums last night. Well, I must say in my system the 422A now bested the Takatsuki 274B in all areas. It was just a sweeter more musically engaging sound with additional texture and nuance. The soundscape was deeper and wider with a more solidly defined location of each performer within that phantom space.

I think I would distill the whole sound as more resolving but with greater emotional engagement. It really drew me more into the artistry of the performers and surprised me numerous times with goosebumps on some familiar tracks which I hadn’t experienced in a long while. The caveat is of course: I think sometimes our hearing, our physical and emotional state and our systems all just perfectly align, so I’m going to attribute some of my impressions to be related to “it was just one of those perfect nights” and of course we all long for that to be every listening session ;)

I will revisit both rectifiers tonight, but perhaps I should have respected more that I had settled on the WE 422A as the rectifier of choice in my SET’s years ago!
Keep Rolling, Todd
 
Wow Marty, thank you so much for the wealth of information on the full compliment of tube types in the Horizon. I’m fortunate enough to have a couple of backups of WE 422A’s since I use them in my SET monos. In fact it was the first rectifier I rolled into my Horizon before I got the Takatsuki 274B.

I’d pretty much settled on the tube complement that Steve is using and David’s recommendation of the Tungsol BGRP’s. So I snatched up two pair of NOS Tungsol BGRP’s when they were more available(figured I’d have a backup pair but ended up using them with adapters as the input tubes in my SET’s).

I think the dilemma with settling on tubes early on is that we all didn’t know how long the actual break in time would be for the Horizon, And for me, I was also waiting on my Taiko Extreme and then had to wait for it to break in, not to mention now having the XDMS alpha as a new variable.

Anyway Marty, you inspired me to swap out the Takatsuki 274B with the WE 422A for a long evening of listening with a familiar compliment of albums last night. Well, I must say in my system the 422A now bested the Takatsuki 274B in all areas. It was just a sweeter more musically engaging sound with additional texture and nuance. The soundscape was deeper and wider with a more solidly defined location of each performer within that phantom space.

I think I would distill the whole sound as more resolving but with greater emotional engagement. It really drew me more into the artistry of the performers and surprised me numerous times with goosebumps on some familiar tracks which I hadn’t experienced in a long while. The caveat is of course: I think sometimes our hearing, our physical and emotional state and our systems all just perfectly align, so I’m going to attribute some of my impressions to be related to “it was just one of those perfect nights” and of course we all long for that to be every listening session ;)

I will revisit both rectifiers tonight, but perhaps I should have respected more that I had settled on the WE 422A as the rectifier of choice in my SET’s years ago!
Keep Rolling, Todd
Todd, we all have those "perfect nights" of which there are too few!! It's the other nights that you end up saying to yourself "what the hell was I thinking?" that's the problem!! Most importantly, have fun!
 
  • Like
Reactions: ctydwn
I am going to do some rectifier rolling today. Not sure why since what I am hearing with my Acme 274B sounds so good. I know a lot of this is due to XDMS.

Will report back.
 
I am going to do some rectifier rolling today. Not sure why since what I am hearing with my Acme 274B sounds so good. I know a lot of this is due to XDMS.

Will report back.
Please do.
The ACME 274b is not really my favorite recti but then again I didn't try it in the Horizon :oops:
 
  • Like
Reactions: acousticsguru
OK time has come to post a few sentences about two tube types I've stumbled upon in my quest to find some "new" tube types which are a)good/great performance wise b)preferably cheap(ish) c)rare.
Big big portion of game related to those two tube types I did with a help and in cooperation with @marty and I'm sure he'll chime in particularly related to the performance of the beam tetrode tube known to outside world as 6384. Most probably not many heard about this tube type but it was produced by Bendix for military purposes to withstand ultimate operational conditions and when you hold the tube in your hand you certainly feel this "sick" attention to detail in terms of engineering. Tube is relatively small in comparison to other pentodes/tetrodes but weight wise its on par maybe even with KT170. Not to write in my words I'll just copy/paste from the text I found online:

"6384 The debate often taken up in various magazines, about which 6L6 type is "best," seems a bit silly if the 6384 is compared to the available 6L6 types. Even the Tung-Sol 5881, Mullard EL37 and Genalex KT66 look like fragile and lightweight toys next to the Red Bank tube. So it's safe to say: you won't see the likes of this tube again. The base is some kind of ceramic material, and is one of the few ceramic octal bases I have ever seen. The construction is the same luxurious style as the 6094, with all-ceramic spacers and a heater block. The pinout is the same as the obscure Tung-Sol 6AR6, a very similar rube to the 5881 physically but not quite the same electrically. Still, the 6AR6 or 6384 can be easily substituted into a 6L6 socket with rewiring or an adapter, and are rated closely enough to work well, though the 6384 makes the 6AR6 look pathetic. Extreme scarcity means we had only one 6384 to test, a new-in-the-box original Red Bank. The plate rating is 750 volts at 30 watts, which is outrageous for a 6L6 type and more typical of the infamous Mullard EL37. Yet EL37s bring $200 or more on the current NOS market, while 6384s are scarce but have nearly no value. It shows how narrow-minded the gurus can be. Simply rewire your socket or use adapter and you can use this Beastatron. Tests showed that it is indeed a beast. At 300v 50 rnA, distortion was 0.77%, lower than that of a typical Tung-Sol 5881. Peak output was 9.8V, far more than most 6L6 types and even better than a KT66. I briefly put 500v 75rnA into the cube, and it continued to work without showing red spots on the plate."
Attached is also original Bendix leaflet with all data. So I managed to secure a quad of NOS ones with several spare tubes but based on the ruggedness these will live a long life. Now since I got my H as I wrote in my previous posts I've rolled decent number of top tubes in terms of double triodes and as Marty said definitely ECC32/31 is the tube which is keeper in my system. It just shines more bright above the rest of the pack. Pentodes I also wrote about and used almost exclusively KT170 which is good option but definitely not the best as El156 and Siemens f2a were above it but due to insane prices of those I don't use them and this was a main driver of a quest to find something in this ballpark performance wise but more into KT170 price wise. 6384 fits this bill perfectly except availability but OK - Marty and myself are fine (selfish this time but sometimes you need to be :) ). Also Marty still prefers his Mullard el34 xf2 which is of course super cool as there are no universal solutions for different systems and ears but he can give a nice insight into differences of these two types (i don't have el34 xf2). To me 6384 in a combo with Mullard ecc32 provides most palpable musical experience with nothing in spectrum to stand out and hurt hearing apparatus but rather being seamlessly blended together with exceptional musicality. There is vast staging but still not being overblown where you can position the musicians on the stage with pinpoint accuracy. Details are there in spades while there is also great dynamics present. But to me color of the tone and musicality is the name of the game so these reminiscent tubes of the cold war era are a keepers for me.
Coming to the last portion of the puzzle is the recti and this particular one was showcased by Marty. I do have tons of different ones but the latest and maybe sweetest addition to collection is again a tube from the same era and same producer being known under the sky with the code name 6106. I won't go into tube details as details are attached as pdf. It is again a brutal demonstration of quality in a small package and all I wrote above was produced with combo Bendix/Bendix/Mullard. I'll try U52 as per Marty advice as I have it and see where this train leads me, but for time being I'm super happy with this combo.
Few pictures as always to visually support the writing :)
 

Attachments

  • 6384.pdf
    518.8 KB · Views: 8
  • 6106.pdf
    448.9 KB · Views: 13
  • 133253B9-8D41-43BD-BC68-E495B33BE533.jpeg
    133253B9-8D41-43BD-BC68-E495B33BE533.jpeg
    285 KB · Views: 36
  • BFCF938D-0E68-4937-8299-B7941728FD7F.jpeg
    BFCF938D-0E68-4937-8299-B7941728FD7F.jpeg
    285 KB · Views: 33
  • D5801843-E711-4338-BF23-8CB27F5877CB.jpeg
    D5801843-E711-4338-BF23-8CB27F5877CB.jpeg
    220.6 KB · Views: 29
  • FA499039-ECA0-410F-87A6-88591A5F974F.jpeg
    FA499039-ECA0-410F-87A6-88591A5F974F.jpeg
    211 KB · Views: 23
  • FBA070CC-9969-4198-A7F2-68DF65F3B6D5.jpeg
    FBA070CC-9969-4198-A7F2-68DF65F3B6D5.jpeg
    221.2 KB · Views: 27
  • B76BC373-B0ED-43C2-8C7A-81758D468F69.jpeg
    B76BC373-B0ED-43C2-8C7A-81758D468F69.jpeg
    203.8 KB · Views: 29
FWIW, here are my verbatim notes I sent to Goran on the 6384 some weeks ago....but all credit to him for the excellent sleuthing to find these things!

"It is a without doubt a remarkable tube. To begin, frequency response is excellent. It is not a big bass heavy tube, but a well balanced one. Next, it is the lowest distortion pentode I have ever heard. That matters. There are certain things that are irrefutably sonically important. Frequency response and distortion lead the list. It excels in that latter category. The third thing that is undeniable is it its uncanny ability to avoid oversaturation. That's certainly tied to its low distortion but is not quite the same. It is the ability to ovoid overload that is perhaps the strongest asset of the Mullard XF2. Well, the Mullard meets it match in the 6384. That thing is impossible to overload. Recall the write-up I sent which stated:

"The plate rating is 750 volts at 30 watts, which is outrageous for a 6L6 type and more typical of the infamous Mullard EL37. At 300v 50 mA, distortion was 0.77%, lower than that of a typical Tung-Sol 5881. Peak output was 9.8 volts, far more than most 6L6 types and even better than a KT66. When 500v 75 mA was briefly put into the tube, it continued to work without showing red spots on the plate".

It is, in short, a beast. Dynamics, not surprising, are excellent from the macro perspective. There is only one question for me that remains, and that is whether, with increased use, it becomes a bit more supple and less rigid. Put another way, after 3 days I put back the Mullards late last night and in comparison, one can see differences more starkly. As soon as I put on my first piano piece, I felt that the Mullards spoke a sonic truth that wasn't just quite there with the 6384. Same for human voices. The "human" factor as well as piano realism is what makes the Mullard's extraordinary. But without hearing the 6384, I would never have realized the minor shortcomings of the lower register's articulation of the Mullard vs the 6384. The piano left hand was oddly ever so slightly but minimally better defined with the 6384. but the EL34 sounded more like my Steinway, if that makes any sense. On orchestra pieces, all the elements are there in glorious definition with the 6384, yet the Mullard sounds more like what I hear in the hall due to its more authentic musical portrayal of individual instruments. These are not night and day differences to be sure, but they are there and noticeable.

There is no perfect tube. The question is, will the 6384 become more supple, more approachable, and more "human" or "musical" with more break-in? In some sense the point is moot. Each tube does things the other cannot. I sense that the key is pairing each with its most complimentary triode. The 6384 is a definite benefit for the bottom register of the Sylvania 6SN7W/B65 of which the bottom is not that tube's strength. But the mid and top of the B65 with the Mullard is a gold standard that I doubt will ever be surpassed, at least for me. However I haven't explored the Mullard ECC32/31 plus 6384 nearly as much so that's a project that's next up on the list of "to do's" as the ECC32/31 may be the best overall of the "6SN7" tube types from the limited listening I have done
."

Considering the 6384 costs less than half of a Mullard xF2, that's a great buy by any standard! A very impressive tube sonically, and built like a battleship!
 
Last edited:
OK time has come to post a few sentences about two tube types I've stumbled upon in my quest to find some "new" tube types which are a)good/great performance wise b)preferably cheap(ish) c)rare.
Big big portion of game related to those two tube types I did with a help and in cooperation with @marty and I'm sure he'll chime in particularly related to the performance of the beam tetrode tube known to outside world as 6384. Most probably not many heard about this tube type but it was produced by Bendix for military purposes to withstand ultimate operational conditions and when you hold the tube in your hand you certainly feel this "sick" attention to detail in terms of engineering. Tube is relatively small in comparison to other pentodes/tetrodes but weight wise its on par maybe even with KT170. Not to write in my words I'll just copy/paste from the text I found online:

Great write up.

Have you compared the 6384 to the EL51?
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu