Is you Amplifier only as Good as the Tube Brands?

In terms of choice of tube to put into a new production amp, the most important criterion is availability. The manufacturer must be able to access tubes with ease, including replacement tubes requested by the buyer or the buyer's shop. Price also comes into play. Given that everyone has different taste and different system requirements, it makes no sense to source expensive and difficult to find vintage tubes when that particular tube type might not be ideal for the customer; it makes more sense to use something cheap and reasonably reliable.

My Audio Note Kageki came with fairly exotic and expensive vintage tubes in it. But, this is a REALLY expensive amp. Still, the particular tubes were not exactly to my liking and I found alternatives that better suited my system and taste. In this case, cheaper tubes as the original tubes would not have appreciably reduced the price of the amp, so it made sense for Audio Note to use the expensive vintage tubes (if only to keep up the premium status of the amp), but, with less costly amps, I think it makes sense to use currently manufactured tubes.

I agree with Chervokas that the single most important factor in sound quality, and price, is the output iron. Very good transformers are critical to the sound of tube amps. Circuit design is pretty well understood these days, so it is more a matter of implementation and in that respect, there is no getting around the need for good iron (unless you go the OTL route, but, that is another story).

 

I just purchased an LTA microzotl MZ3 which is latest version of Berning’s small affordable amp. To say that it is a revelation is understatement. I happen to have very sensitive speakers so I can drive them with the 1 watt it produces. Sounds spectacular with very affordable 12sn7 and 12at7 tubes, so this is definitely a case where the magic is in the circuit.

 

I keep hearing great things about this amp. What speakers are you using?

 

I have Teresonic Magus bookshelf speakers which use Lowther DX65 drivers which are about 100db. It can also be used as a pre or a headphone amp.

 

I'm not educated enough to give an opinion on it, other than with guitar amps, which in some stages
most certainly make a difference, and depending on the amp and the tube.
I look forward to reading more of what folks have to say about it.

 

Judging sound quality versus tube brand is very subjective at best. For my customer repairs I use Sovtec or EH. Excellent QC and affordable in bulk. Plate to grid coupling capacitors in tube amps get a little leaky and can change the bias on the output tubes. This should be your primary concern when servicing tube amps other than power supply electrolytics. I use orange drops as replacements. Do not replace original caps with upgrades such as polypropylene. They have a higher Q and may alter the sound and be too bright. Any capacitors in the driver and pre amp circuitry that go from plate to grid should be checked for leakage. Most resistors in vintage tube amps use carbon composition They drift up in value before they dive and smoke. Any suspects should be replaced with fixed film resistors. Most troubleshooting can be done with a good VOM meter however I prefer a VTVM because of the very high input impedance. I worked in the consumer electronics industry as a technician my entire adult life. Now that I'm retired I still enjoy repairing vintage equiptment as a hobby. Many of these older units have sentimental value to some people so repair costs are secondary.

 

Nice!

In my "leftover parts/upgrade losers" system that I like to experiment around with, I have an original microzotl amp/headphone amp that I got back when it came out, I think for about $600 (hand made by Berning himself!). I use it now with a Hovland HP-100 preamp and Lowther Medallion 2 speakers as a multipurpose amp for TV, FM, CD, LP sources to play with. Because this amp uses 6SN7 tubes for the 1 watt per channel output, I use it to more directly get the "flavor" of each brand and vintage of 6SN7 tubes I've collected over the past few years. Here I have two vintage '59-'60 Tung-Sol 6SN7s installed along with two vintage Telefunken ECC801S (12AT7), and the sound is really nice.

 

BTW- I use Mullard 12AX7 MC1 long plate square getter tubes in my tube amp. Expensive and around $500 a pair used. I rarely find this tube new and only one tube, not a matched pair.

 

Very cool! I like the idea of flavor testing 6SN7! Do you have some top favorite 6SN7? I really like early Sylvania chrome top 6SN7GTB, but I'm looking for more options to try in my preamp. The Sylvania is nicely balanced from top to bottom with great clarity of vocals and good dynamics. I've also tried the russian jungle tubes from Upscale and Raytheon 6SN7GTB.

 

My experience has been the right/wrong tubes can make/break a given amp. And the right tubes for one amp may sound lousy in another.

I have found that mediocre amps can often be made to quite good with the right set of tubes. I have also found that great amps can be made to sound downright bad with the wrong tubes. So my opinion is that the choice of tubes is absolutely critical in achieving the best sound.

But this does not mean that more expensive tubes necessarily sound better than cheaper tubes. Its all about finding that perfect sonic recipe of tubes for a given amp and system.

 

Actually all 6SN7 comparisons are made in the context of my main system's amp first, and the best quartet I can find is used there. The remainder can be used to compare with each other in that microzotl 1 watt/channel system, which of course will only reveal which two work best in that system, cause as we know it's all system dependent. But it's unique for an amp to even use 6SN7s as power output tubes, and the sound quality differences in that context are readily apparent.

Currently I am using a quartet of Sylvania 6SN7GTA type in the main system amp, these also with chrome tops, three made in late 1953 and the other in early 1954 (shown below). They have a similar internal structure to the famed Sylvania 'bad boys' which were produced just before these in the prior 2-3 years, but compacted into a short bottle instead of the clear tall ones. They replaced the Tung-Sols from 1959-60 as best in the main system amp, which had their own virtues too, but I don't believe quite the extension and expression in the frequency extremes -- both beautiful in the midrange. The current best (with the white labels)...



Other 6SN7 tubes of my acquaintance: 1960 re-branded Tung-Sol, current production Tung-Sol, early '50s Hytron, Sylvania VT-231, Hytron 5692, RCA dark glass VT231, RCA 6SN7GT, current production Electro-Harmonix, early Russian military 6H8C, later Russian 6H8c similar to Upscale's "jungle tubes", and the more recent Sovtek 6SN7GT. Of the below In the microzotl I like the Hytron 5692 and the RCAs the least, The Tung-Sols and Hytron 6SN7GTs the best, and the others in between. Finally- I really haven't spent much time making these comparisons, so who knows how I'd hear things today, if I had more time for doing it.

 

We are shipping our new amps with Phillips 12AT7WA - from '88 - of which we landed about 700 of in 100 count boxes, and 50's era Brimar 13D9's. We were lucky enough to find several hundred of those in the UK last fall. Finally, we have hundreds of great old RCA 12AU7 black tops. The new amps have Marvel transformers custom made in Chicago, which we had to make a large order for - to ensure they custom manufactured our design for the new 2019 Avian Series amps that are finally shipping now. We also have about a hundred NOS 50's era authentic Brimar 6060 Yellow T's, Seimens, Tungsram, and Valvo ECC81's as optional while they last.

The only currently manufactured tubes we found to be comparable are the Gold Lion gold pin 12AT7 & 12AU7's from New Sensor. They are expensive - running over a hundred per pair. Yet they are finally approaching some of the better NOS stuff still left out there. It is unfortunate that we are finally running out of the great old glass, but it is what it is. At 65 I am just so very glad I got to own so many historic tubes in my lifetime, and was able to listen to them in some of the world's best tube amps. Generations from now I can only hope that someone starts to manufacture them with the quality that the great old tube factories were able to churn out - for the war efforts - when lives really did depend upon their quality.

 

No. If the OP's thread title was true Fisher 400 receivers wouldn't cost $1000.00 restored.

 

Power amp, no experience.
Preamp or preamp section of intergrated amp with 12ax7, 12au7, 12at7. The difference in sound when pulling out Chinese and Russian tubes with NOS Mullard long plated mc1, Amperex bugleboy and Telefunken ribbed or smooth was and is incredible.
These tubes to me turn a $1000 preamp into one at double the value. Biggest change in sound, for the money , ever experienced.
John M.

 

Whoa.

Brimar sure made great tubes. The best 12AU7 type I've found for my phono stage after many comparisons is a Brimar 13D8.

 

I am going to go out on a limb and ask that if each tube changes the sound of your amplifier by that much of a degree exactly then where is the high in high fidelity?
no I am not anti tube: www.plattamp.com

 

It gets higher when you put in better tubes (for a specific application, determined by comparative listening according to individual taste), and you should hear more clarity, dimensionality, tonality, subtle details, timbral accents and shadings in instruments and voices, and so on through the audiophile's mostly inadequate attempts to describe sonic improvements.

 

If my amplifiers changed that much with different tubes, I'd go back to solid state for consistency .

 

Where is it regardless? Do you need someone to tell you if your equipment is high fidelity and that it is achieved with only "X" set of tubes? Do you have enough experience with live and/or recorded music to make your own value judgments?

It's all just shades of perception and consensus.

 

One of the main reason people use tubes is to tailor the sound and presentation of the music to their tastes... You can refer to the above post if you need to.

 

Do you need someone to tell you if your equipment is high fidelity and that it is achieved with only "X" set of tubes? -Absolutely not
Do you have enough experience with live and/or recorded music to make your own value judgments? -Absolutely

I'm not the one here putting all my tubes in one basket. OP asserts tubes make the most difference. Almost every tube sounds different if you believe what everyone tells you, and some claim to a high degree. So if thats the case, I am just raising a thought provoking question, a mental excercise. Do tubes provide the best fidelity? or the best sound(for reasons other than fidelity), because if it's different tube to tube, that kind of throws the "fidelity" part out the window.

I know there's differences from tube to tube, especially when you take them out of their linear range. there are gain differences, all sorts of stuff. thats part of the fun to me as someone who makes and sometimes records music.

 

Well, as someone who makes and sometimes records music, you should know that the gear you use consistently can have a different sound from performance to performance. I only wish my bass sounded exactly the same on each and every gig. Guitarist change tubes to get the sound they want all the time. That change in sound has zero influence on "fidelity" (and I use the term loosely) because the sound they want, is the sound they want.

So to imply that a different sound coming from different tubes is some kind of problem, fidelity-wise is something I don't get... What is fidelity when comparing playing a small venue vs. a large one vs. outdoors?

I get that you are talking about stereo, but my overall point is, that - The sound you want, is the sound you want.

It's an interesting exercise and discussion... My take is that reality has no defined "fidelity". Fidelity in reality is defined by Stevie Ray Vaughn, who said. "you turn the knobs until it sounds good." In the case of stereo, you change the tubes until it sounds the way you want.

 

I agree with you. Tubes are a large part, but you have to start with a large power supply, quality transformer's and other quality components.

Still, I have a Fisher 500C receiver and it is a very heavy complicated receiver, with something like 19-tubes.



Underside view from the net...

 

I will say that a good tube circuit will sound good with just about any tube that it was designed for. Different tubes can change the flavor but it has to be a good sounding unit to begin with.

 

Interesting that consistency is more important to you vs best sound quality. Once the best tubes are in my amplifier, the amp is not inconsistent in sound quality from day to day. I never heard SS sound as good as high quality tube amplifiers, but some would disagree with me.