TechTubes - The return of Blackburn

[awedio]

First impressions are always based on the physical appraisal of something, and I have to say that I am impressed with the apparent quality and appearance of the product. The packaging is bar none the best I have seen for a 9-pin vacuum tube (see picture). The internal structure is quite different from what we are used to seeing and the execution/construction looks very good and clean. All of the pins were straight on all four tubes I received.

As to comments on the use of the Blackburn label - these are not Mullard reissues! Not even close, they are a very different kind of tube. They are made in England at the Blackburn Microtech factory which used to pump out Mullard tubes way back when. Hence the moniker "Blackburn Legacy Series". Are they trying to ride on the name and fame of old Mullard/Blackburn tubes? Yeah, sure! It doesn't bother me as a marketing ploy because, if you think about it, no-one else would have ever had the insane idea to re-make the vacuum tube at a CRT factory in England in 2009. It's clearly a passion-driven project fueled by the very history of the place - so "Legacy" it is.

There is no doubt that the appeal will be there for NOS tube aficionados as well as guitarists enamored of "that British sound, gov". If it helps Blackburn succeed in this crazy endeavor more power to 'em!

It also strikes me that we have here an attempt to re-make the reality of the vacuum tube without necessarily re-inventing it. I would not be surprised if some of the internal parts are sourced from other product. Again, no sin here if the resources weren't there to start completely from scratch. A wheel is a wheel but a forged magnesium one might perform better than stamped steel...


So there's my introduction.

[awedio]

As in the order in which I tried them (e813CC - 12AX7 version), let me begin with the most subjective appraisal - my observations of how they performed in my bass guitar amp (Peavey AlphaBass, 3x 12AX7, 1x 12AT7, 6x 6L6GC. All-tube.) I will do my best not to veer off into hyperbole, but electric instrument musical tone can be tough to verbalize.

I first tried replacing one tube at a time, V1, V2, V3 - gain, tone stack, pre-driver respectively), replacing a Mullard, a Raytheon and unknown (GE?). The sonic effect was very similar in all three positions: a fuller sound, plenty of lower mids and a very solid bass sound with clean overtones. I liked the change best in V2 position. Bass players will love these tubes! There was an overall boost in midband richness while actually augmenting the fundamental and a very clear and haze-free sound with clean tone.

I tried overdriving the tubes - and what I heard was a bit cleaner with fewer harmonics. I could still hear the note fundamental quite clearly through the distortion - there seemed to be more headroom overall.

I have to say that by the time I switched out all three 12AX7s I had too much of a good thing. The sound became too clean and fat for my tastes. The Mullard I usually use in the V1 spot has a more chimey response and makes more noise and harmonics when overdriven, which I like. I have never found a better tube for this application than the Mullard, it just has more going on. Like Trout said in the other post about techtubes, V1 in a guitar amp is responsible for defining a lot of the tone in a tube setup, it's the first amplification of the pickup signal. The Mullard just gives me the tone I want.

TechTubes themselves are not recommended for the primary gain device in a guitar amp due to possible unwanted microphony. (read about it here: http://www.diyaudio.com/forums/showt...10#post1871110 ) From what I gather from my own testing, the TechTube E813CC works best in a secondary or tertiary stage anyway - it almost acts like a supercharger for your tone. The addition of just one of these gave me plenty of extra rich, developed and authoritative tone that seemed to drive the music forward and would have the ability to help one cut through the mix in a live situation. I still preferred a "dirtier" tube in the first gain stage.

All in all I would recommend these primarily for Blues and Jazz players for guitar, and for any bass player using 12AX7 tubes. I am not sure how they would fare for a speed metal demon shredder - they seem less "crunchy" than other tubes. But my final observation was that I was inspired to play longer without getting bored. As a solo bass player in my studio, it's hard to keep myself entertained! But I did sense an inspired/improved understanding of and connection with my instrument, and that can't be made up or imagined too easily!

The "go to 11" suggestion is based on what might happen in a very high gain amp. I sometimes felt that in my bass rig I couldn't drive them quite hard enough to see what they would really do when pushed. Leave that to the guitarists to find out...

[awedio]

What I heard in my bass amp did not prepare me for what was next. The first night I put the TechTubes in my preamp I was up until 3am listening. I was captivated by what I was hearing. But I get ahead of myself...

I could perhaps mention that my preamp design does not use 12AX7 or equivalent. The cathode follower output stage is designed around a 12AT7. It is a tube-based CCS arrangement under the follower. A 12AX7 can be used in a pinch but is pretty far from ideal. Unfortunately I was unable to ascertain the working parameters for the tube because the circuitry is shielded in an metal box within the chassis that is hard to get to, and I no longer have the circuit breadboarded. I heard something like clipping at higher volumes suggesting that the Techtubes might be working near cutoff at times. No fault of theirs, this circuit wasn't designed for them.

And yet...

I could scarcely believe the difference in resolution I was hearing. Before I go on like an audio reviewer about this or that, allow me just two brief examples:

- On a female vocal pop recording (CD) which I already knew had multi-tracked vocals, I was sure that her voice had been overdubbed perhaps once or twice. On a certain track, I could now hear FOUR distinct overdubs. The separation was surprising, yet not distracting.

- On recordings of acoustic instruments, piano in particular, the trailing decay of notes was clearly improved and lengthened. Cymbal crashes were appropriately metallic and hashy but with less of a white-noise aspect which many systems impart.

There. I won't torture you all any further with endless descriptions of this or that recording. Suffice to say, I thought I was hearing less distortion (more like IM than harmonic) a clearer rendition of vocals and instruments with better separation, and deep well-defined bass. Actually the bass was a nice surprise esp. given that I did not expect the 12AX7 as a buffer to have much drive.

I would venture that anyone reading this forum should have enough skill to design around this tube and get great results. If it could perform this well (sonically) in an inappropriate circuit, then I really feel confident in recommending it to a diyer.

One more thing - I have been designing audio gear for 10 years now; the process of comparing components and crossovers etc. can be ungratifying a lot of times. The reward is when your favorite piece of music sends shivers up your spine, but it happens rarely. I did get that effect when listening to some well-worn recordings of mine and that feeling always leaves an impression.

[awedio]

OK, OK... I am just about hearing your accusations by now - "Shill!!!"

I can honestly say that I have no affiliation with or financial interest in Blackburn Microtech. But I am impressed enough to daydream about offering my services as a distributor if they ever got off e-commerce and go retail!!!

So, to keep it more brief and also include a not-insignificant wrinkle, here's the synopsis with two phono stages each using 4x 12AX7s:

My observations were all positive and very much in the same vein as above with my pre. Very resolving sound, top-to-bottom. Excellent clarity and separation of instruments, etc. The thing with phono amplification and eq is how sensitive it can be to changes. For example, I found myself wondering how my MM cartridge was doing with so much less capacitance loading it? It didn't sound bright or harsh. Adding back in some capacitance softened things a bit but was not too significant.

Then my buddy tried the tubes in his phono pre, he is using a MC cartridge and step-up transformers. He had nothing good to say about the tubes! He had nothing bad to say either, but to his ears there were no improvements such as I heard. He felt that the treble sounded rolled-off or closed in. So was there possibly some shift in the equalization? It doesn't take much error in the RIAA curve to be heard, -0.3dB is not a lot until it's across 2-3 octaves. Without the time to do measurements, we just don't know why his results did not match up with mine.

But I can say for sure that the Techtubes seem to have less thermal noise and hiss when compared directly to JJ, Ei and Ge tubes that I have been using. I cranked everything up and the TechTubes were quieter. Once again, with proper design and some diy skills, I still think that these tubes will be able to outperform the traditional variants. I am eager to hear from anyone else who has tried these... in due time.

I want to apologize for the lengthy posts but hope I don't have to. I have been waiting for these tubes to be released for some time and was already excited before I got them. I feel like I have a lot to say! I've had about a week with them and I am just very impressed with how they performed right out of the box and plopped right into any circuit I had on hand to test them. YMMV, as it did with my phono friend - but if nothing else I think diyers stand a good chance to wring out a lot of potential here.

I will try to do the same, with some breadboarding and measurements. If I can stand to take 'em out of my audio system, that is!

[Geek]

Thanks for the info!

This sounds promising.

Cheers!

[KaffiMann]

Hi

I was going to order some tubes from techtubevalves.com just now, and i wasn't aware of the news from 23rd of september:
Historic Blackburn firm in administration (From Lancashire Telegraph)

Anyone know what happened to the brand spankin' new tube production?
Are there any leftovers? Where can i get some leftovers?

[piero7]

http://www.techtubevalves.com/ is gone!!

[Sch3mat1c]

New age industrial styling. I bet Chinese 12AX7s measure closer to spec and perform better than those deformed things.

Tim

[awedio]

These tubes were totally awesome. I have just a few, and I wouldn't part with thme at any price. To the naysayers, skeptics and luddites:
::



You Lose!!! You Lost!!! And we all lost the last great push (for now) to further vacuum tube technology. I can't believe those who post their opinions without ever having heard... see above, I think you're up there.

[Arnulf]

Crazy much, are you ?