Just throwing this out there, but perhaps you just have not rolled the right ones to notice a difference. There are many tubes out there that sound quite similar and there are also many in those same family’s that sound quite different.
For instance, a Mullard ECC82 Long Plate Square Getter, sounds absolutely nothing like a Siemens ECC82 Chrome Plate . . .
Just out of curiosity, care to share the names of some of those fancy tubes?
I’ve let most of them go. The last tubes I think I really liked was the 6550 grey plate tung sol and they sounded just a little bit better than the kt88 jj’s and the new stock mullard’s.
I’ve gravitated towards mullard 7 notch 5ar4’s which fetched a pretty penny cause they’re getting hard to find but I’ve also set them side by side with new stock 5ar4’s and there was a slight edge but a huge price difference. I have a Japanese 5ar4 that sounds just as good as rca 5ar4’s.
my last favorite nos input tube was a siemens e83cc and as I’ve said before, maybe slight edge over some of the less expensive tubes. I’d have to go through my list of current input tubes to see what I have in regards to new stock and old stock.
Currently running Voskhod Soviet 6N1P-EV / EB output tubes and they sound just a good as my 7308 nos tubes but they are a little noisy but it doesn’t bleed into the headphones, so it might be a breaking in phase. Paid 10 bucks a piece but you can find them for 5.
I’ve enjoyed the nos mullard input tubes and others. I’ve owned the Brimar’s. Currently have phillip input tubes. Also have bugle boy input tubes. I’d have to dig through pictures and posts of all the tubes that have come and gone. Maybe I shouldn’t have done so much house cleaning on the old tubes but I don’t want that giant box of “what if’s”.
But I’ve also changed tube amps quite a bit lately, so only my rectifiers have stayed the same, my input and output tubes have changed quite a bit. New amp, new learning curve.
Nice, and thanks for sharing. The thing I have noticed is that there are variations in sound depending on the year manufactured, as well. So, having some big named tubes does not mean they will produce the sound the name is famous for. For instance, latter years Mullard EL84’s tend to sound a bit bloated in the mid bass and hazy in the mids with rolled off highs, and the earlier versions are as detailed and clean sounding as can be with more of a subbass focus, and good top end extension. Over the years the construction of tubes within each brand continued to change, so they don’t all sound the same as a result. That’s why I always like to mention the date a tube was made and a description of the inner construction, when I am describing it’s sound signature.
I’m with you, I’ve owned the older 1950’s up to current. I do agree, some definitely have an edge or better sound than others. I’m just stopping my habit of paying (I just order a 200 dollar tube…) more than I should for tubes. I’ve got one coming in this Saturday to compare (not even sure the exact year, brand and model honestly, I just trust Brent Jesse) against some 50 dollar tubes. The Russian output tubes were suggested as a starting point as the Decware CSP-3 was designed around that tube, it’s durable and long life. The CSP is a pre amp let alone headphone amp, so the output tube has less changes over the sound as the input tube. I’m super tempted to pick up the Tabboo to complement this pre amp.
This is generally true, however, there are some tubes that are simply better than others.
It helps immensely to know what tubes your amp responds best to. My amp responds amazingly to good rectifiers. And as a bit of counterpoint the performance metrics of my rectifiers did increase as the price I paid for them went up. Maybe thats an exception. However, this also applies to new production tubes - you generally get better the higher up the price ladder you go until you reach a point that it just becomes about sound signature preferences. The question is: what is the $$$ that divides performance classes. Thats a hard nut to crack.
Of course you dont have to pay $$$ to be happy with the sound you get from a tube amp. My amp sounds perfectly fine with a $40 set (4 tubes) but, it sounds amazing with a $400 set. Now, I was willing to risk that expense and accepted it as a possibly foolish venture.
I would never push that $400 set on anyone because there are too many variables involved that makes it impossible for me to guarantee that the tube that I think is Optimus Prime wont turn out to be someone else’s Starscream, no one likes Starscream. And I would never want to give anyone Starscream. Now if I could guarantee at least a Soundwave level tube then rock n’ roll, but I cant.
Can I ask questions about tubes here? Or is this for discussion of people with experience only?
The more I learn about my sound preferences, the more I think “ooo tubes!”. The problem is I have primarily liked low impedance headphones or planars so far. Which is why I have kept my amp exploration primarily in the solid state/hybrid world.
I find myself preferring the sound of “smoother” SS like the ifi micro signature. And I want to hear the things that people attribute to R2R in terms of layering, natural timbre and sound stage. The only thing with a tube in it that I have heard is the xduoo ta-30. And, in hindsight, I think it would currently site in my top 2 with the signature. This is also why I want to explore class a amps as they are generically described similarly.
But, what I want, is something that I can “just use” with most headphones. This probably means relatively neutral tonality, smooth but clear, maybe leaning slightly toward warm since I don’t like analytical results.
Keeping in mind, that I like to spend the “minimum necessary” to achieve the goal. So I am not going for the last 5% in sound. A reasonable solution that has a wide range of practicality is far more valuable to me than something that makes one headphone sing but will be poor matches to others in general.
Can people make a “complete stack” recommendation with dac + amp (or combo!) that would take advantage of tubes but fit what I just described? (OTC probably required I think?)
Is it even possible?
Thanks!
Consider Bifrost 2 with the hybrids mentioned here (I’ve heard the Lyr 3 and MJ2, not the LP):
As for versatile non-hybrid tube amps, the starting point is probably a used Pendant OG (try to get the most recent version immediately preceding the Pendant SE).
Totally agree with your points - I think there actually are some P-P tube amps for headphones, but in general the impedances are higher (which tubes like) the effect of parts is more obvious and the sensitivity is higher, so OTLs rule the roost. Ampsandsound is the exception, and their small signal transformers are excellent.
I will say though - have you ever looked inside the Darkvoice or Lafigaros? They’re cheap, but the circuits are actually really good. I’ve swapped some nice tubes and better/quieter power supply parts in and been very impressed by what I heard. The grounded anode and choice of triode-strapped pentodes actually works really well.
RE: 1950’s sound, there’s actually some excellent bandwidth recordings. One that comes to mind is ‘Hands Across the Table’ by The Cadets. The lead singer’s voice should sound 10 feet tall on a good setup. It’s difficult to properly assess these however as they are often poorly transferred to digital. There’s a barkiness that 50’s pentodes had that is distinctive and makes things sound larger than life. Most of the triode gear from the 30’s and 40’s by contrast is very immediate and transparent sounding.
What’s different?
Might see if I can get one here for comparison.
There’s unfortunately a lot that you just can’t learn from the manuals and books, primarily because back then a large number of companies were making tubes, often with parallel technologies, but in relative isolation from each other, around the world.
Add in the fact that tubes are really still made by hand, with machine help, and you have a product which requires a certain amount directly passed down knowledge to build, and we’ve lost an enormous amount of information on tubes. I’m lucky to have a friend who owns a tube factory and works on old electronics here in LA, and has been a huge source of information and learning for me. He actually has old RCA drawings and internal handbooks, and learned from the lady who sold him the tube factory. There’s all sorts of unusual considerations even lifelong tube collectors would never know without the direct knowledge.
One of the interesting things I learned from him was that 300Bs are actually some of the simplest tubes to make, and 12ax7s one of the most difficult. It’s often easier to get a large tube to perform better simply because construction is straightforward. Small tubes that perform well are actually quite difficult but command lesser prices. The trend towards smaller tubes is merely driven by the need for a given form factor, and post WWII a lot of gear was becoming smaller and more portable - as is the case with smartphones and earbuds nowadays.
Contrasted with the DHT of the early 1900’s, which was actually simultaneously and separately developed in the USA and Austria, smaller and more efficient tubes are also better able to achieve higher power, less heat-transfer loss, etc. I might do a video sitting down with my buddy about the history of tubes and digging deep into the lore he knows of. It’s fascinating stuff.
The corollary to this is that sometimes rare or expensive tubes don’t always sound as exceptional as less expensive tubes… but only very few people have the knowledge to understand what to look for. It also depends on the amplifier. A tube amp that surrounds and babies the tubes with bias point servos and opamp buffers isn’t going to reward tube rolling much. A tube amp with a dead simple circuit and zero feedback (like early W.E. designs) relies on having exceptionally built tubes.
They used to have (and many A&S still do) have noise floor problems.
See here; there may be discussion before and after.
Great information. But I don’t think that the engineers did it all by trial and error. Tuning tubes had to be a thunk out design. And radar sets didn’t just happen.
I want to hear glory stories of tube engineers when science and serendipity do meet.
Yes that is true, and my comment wasn’t meant to imply that it was merely shooting in the dark, but rather that we don’t necessarily have a lot of people nowadays who actually understand how to create new tube types.
One of the factors to consider was that back in the 50’s, the height of tube production, RCA was grinding up and throwing away 50,000 tubes a day because they didn’t meet spec. This was an era when tubes were created because a circuit demanded it, rather than the other way around.
So the question of how the ‘best sounding’ tubes were made is not actually how engineers at the time would have thought about it - it’s largely a facet of our current capabilities which are generally limited to using old stock or replicating existing tube designs. Back in those days, engineers were more familiar with how grid spacing, cathode grounding and relative vacuum or EF potting could effect the impedance, transfer curves and thermal conductivity of a tube. The handbooks of course will tell you ‘make the grid spacers like X to achieve Y coefficient’ but the execution of said matter is then up to the mechanical engineers who are faced with building the darn thing.
As I noted before, it’s rather ironic that new production 300Bs command such high prices, because they’re one of the easiest tube types to build. They’re priced the way they are because of course any tube is costly to build nowadays and 300Bs aren’t in particularly high demand outside the small hi-fi community, but an average 1950’s valve schematic engineer likely would scoff at the notion that there was anything special about a 300B. By then, pentodes, beam tetrodes and even exotic transmitter tubes had already been invented. Companies like Brook who stuck resolutely to triodes were considered old-fashioned by their peers and eventually went out of business.
Transformers are largely the same way - the only way to build or replicate an amazing piece of Peerless, Freed or Langevin (W.E.) iron is to take apart and find out that they’re incredibly complex… trial and error was used to reach design parameters which were determined by folks doing the math. That brings me to the next point which is that the while scopes and some fairly sophisticated measurement tools existed at the time, measuring gear was not nearly as precise a science back then as now. Engineers still had to use their ears, and we encounter some fairly strange designs from say Rein Narma, the chief engineer of Fairchild and Gotham. If you’ve ever heard an original 660 limiter, or Gotham Scully/Westrex system, it’s jaw dropping how good they sound.
Open them up however, and it’s a fairly complex nested feedback design with over 39dB of loop gain, a theoretically ‘wrong’ transformer primary of 1600 ohms, and a host of other strange issues (instability with 811a tubes causing them to self immolate occasionally) So how does the darn thing sound so good?
The evidence on the other side is the old classic Lansing/W.E. amplifier which is simply an input transformer, a pair of 2a3s and an output transformer. As dead simple as one can get - and it also sounds amazing, but in a different way.
(Edit: I totally butchered this)
I can’t recall the name, but it’s an often used quote from, I believe, an EMI engineer which goes something like this:
“If it sounds good and measures poorly, or if it sounds bad and measures excellently, you’re measuring the wrong thing.”
Somewhat ironic given the current day propensity towards measurement. I think the takeaway is that folks back then really had math and design chops, and occasionally made magic based on the pen and paper limitations of the day.
As an extra little tidbit, industrial amplifiers from back in that era tend to sound far superior to commercially available hi-fi. We think of low power, zero feedback and somewhat warm/rolled off sounding amps. But plug in a McCintosh MI200 (if you can find one) and you might be shocked. 400W RMS of DHT power with wider bandwidth than some modern solid state amplifiers.
“If it measures good and sounds bad, – it is bad. If it sounds good and measures bad, – you’ve measured the wrong thing.”
I’ve always liked this quote. It’s attributed to DVR of EAD and KLH.
Thanks for the correction, I knew I was getting it wrong somehow…
This reminds me so much of the Saturn V F-1 rocket engines. To this day we still can not replicate a working F-1 engine.
It was intended more to attribute authorship. You’re welcome and weren’t incorrect - no need to get into the specifics of contrapositives and converse statements!