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Bravo Audio - funny looking little tube amps

Discussion in 'Headphone Amps (full-size)' started by ear8dmg, Sep 9, 2009.
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  1. UmustBKidn
    Well, that certainly is out of character for a Mullard.
    I am curious, what kind of headphones are you using? There isn't anything listed in your profile.
    Regardless of whom you purchase a vintage tube from, one unknown is how long it's been, since the tube was regularly used. Letting it run for a half hour is a good first step, but it might take a bit longer before it sounds better. Simply running it on a tube tester will tell you how good the tube is, but it isn't going to really exercise the tube like regular use will do.
    Vacuum tubes are an interesting device. I spent 14-odd years of my life making very high-tech versions of vacuum tubes. They are finnicky, and their best performance is obtained by using them regularly, and often. Leaving them off for a prolonged period of time, can actually degrade their performance. You need to pick one of those tubes, and let it run for a while (meaning, days, at least) before you pass judgement on it. It may even take longer. There's no precise formula.
    You bought a pair of 1967 Hammond rebranded Mullards. They are the "short" plate variety (meaning they are unlikely to be microphonic, but they are not as good as the 17mm long plate variety). In my experience, rebranded tubes (of any kind) are not quite as good as the original brand (while that is a highly subjective statement, it has been generally true for the several dozen varieties I've tried). You're also using late 60's tubes, which just aren't as good as tubes made 10 years prior (but not nearly as expensive either).
    Two of these tubes for $35 bucks is a reasonable price for them. After you run them for a while (more than 30 minutes, perhaps more like several weeks), I would expect them to sound superior to the stock Shuguang crap that is shipped with the Bravo's. To me, the Shuguang tubes are thin, tinny, and shrill, compared to any vintage Mullard. But its difficult to compare a brand new tube that's been recently burned in, against a 45 year old tube that may have been sitting unused for decades.
    If you want the absolute top quality Mullards, you need to look for the late 50's vintage D-getter tubes, and you will pay easily $100 each for them. Sometimes more. The sound quality of those particular tubes is simply amazing. I own a couple of them, and I paid quite a bit of money for them (more than my Bravo's cost). But I don't think we need to go down that road. You have a decent pair of 67 vintage tubes. Pick one of them, put it in your Bravo, plug some cans in (anything will do), turn the thing on, and let it run for a good long while (days at least), then give it a listen.
  2. UmustBKidn
    That is an oddball tube. There is no Mullard branding on the tube. The only thing that gives it a hint of being a Mullard is the date code. A date code of B2K3 could either be a 1962 or a 1972 tube. Most 1962 tubes I've seen still have a distinct Mullard badge on them. This tube has nothing but ECC82 on it. So I'm a bit confused as to what exactly you bought.
    There are an awful lot of sellers on eBay who are all too willing to label their tubes as Mullards. Anything that is made in Great Britain seems to warrant the name Mullard, whether it was really made by them or not. I can't claim to be an expert on British tubes, but I've seen an awful lot of oddball tubes labeled as Mullards, simply because they seem to carry a similar sort of date code.
    It is definitely a short plate tube with the Gf2 design. 15 quid for that tube is probably a decent price, but again, it's not a 50's vintage D-getter Mullard. As I suggested to the other member, I would let it run for a good long while, before doing any critical listening. I am sure it will turn out to be better than the stock Shuguang tube.
  3. ostewart
    Yeah I got it because of the price really.
    Will see how it is.
  4. money4me247 Contributor
    hey is there any comprehensive list of tube descriptions/pricing or what not somewhere on head-fi?
  5. razor5cl
    My V2 arrived today, but it has a US plug on it and I'm in the UK. I can't use an adapter as it'll burn out, so I'll have to find another power supply to use.
  6. UmustBKidn
    Take a close look at the writing on the side of the power supply. When I checked the description of these on eBay, the power supply is described thus:
    1 x Switching Power Supply Universal AC 100V-240V / 50~60Hz to 24V DC 1A output
    (Auto-Detect International Compatible)

    I don't know if just using an adapter will work or not, but I guess you could just go out and buy a UK power supply that puts out 24 volts DC at 1 amp. If you do attempt the adapter, I would not plug it into the amplifier. I'd first check it with a voltmeter to make sure it's putting out the right voltage (and watch it for a while to make sure it doesn't make the Magic Smoke).
  7. ostewart
    You should just be able to replace the first section of the power supply wit a UK one £10 from maplin.
  8. razor5cl
    I'm gonna try with an adapter today or tomorrow, I think it'll work, as it says it takes 100-240v and the UK is 240v.
  9. razor5cl
    So, my V2 works fine with a US to UK mains adapter, no smoke. Out of the box it sounds good, bass seems a little less prevalent on my DT990 Pros and that's without any tube rolling or significant burn in. I did leave it to warm up though.
  10. 8064r7
    My Ocean arrived today.  Already noticing a good difference by unloading the amp duties from my DAC/AMP and letting the Ocean due its tube magic.
  11. whiteshadow001
    I'm new to tube rolling and I was wondering if the 12au7 tubes were the only tubes the V2 can use or can it use 12ax7's as well?
  12. DefQon
    Doesn't take 12AT7 and 12AX7's. Yes they can work but the 12AU7 has the lowest gain of the triode family, then followed by the 12AT7 and then 12AX7 has the highest gain of all 3. It will overdrive the circuit and lead to distortion so it not a drop in replacement for this amp's circuitry. 12AU7 = ECC82 (European Prem's equivs) and a lot more, plenty of 12AU7's to be found. If you want you can buy an adaptor off ebay that will allow you to roll in 6SN7's.
    As with distinguishing Mullards, the first thing that gives away a Mullard tube, be it a proper re-issue or rebrand is a big O getter that flashes on startup, 4 pinched groves on top of the tube glass surface and a very nice, deep low end and natural sounding treble, mids can be a bit distant and Mullards tend to have a good low-end but laid back neutral mid, treble and non sibilant highs. Detail is there but not as good as the Holland factory Amperex's which also can have a flashing O getter and pinched groves on the top tube glass surface.
    If you want detail and awesome sauce soundstage, genuine and not cheap Telefunken's, Valvo, Philips and genuine Tesla's are what you should aim for.
    But I'd think it'd be absurd rolling $150+ tubes in a $50 amp. 
  13. arcorob
    I have to disagree (respectfully). Maybe its a system source thing but I have a Mullard 12AU7 long plate that is awesome in the Bravo. The reason I like it is because it has forward mids. To me, its the Amperex that are a bit too laid back. I also tried the RCA and GE black plates. They are VERY detailed but they had neutral to flat mids.
    Another good selection is the organ tubes (Baldwin, Hammond)...I forgot who makes them but they are very well made.
    Not a fan of the telefunken either. Very rolled off..smooth but at the sacrifice of detail.
    The Mullard normal grey plate is also a fine choice.
    Secret to the Mullards ? They MUST be authentic Blackburn plant. Not India or Canada. And preference is early 60's
    These would be great if it was just one for sale
    And or if you can find a Blackburn Mullard / fisher branded...OMG ..sweet...
  14. arcorob
    Very subjective..LOL
    The Mullard short or long plate , Fisher branded Blackburn plant are amazing...I do agree though the 17mm long plates are a tad nicer (I have both)
  15. DefQon
    That's your system and your findings that is fine but peoples findings on Mullards are as I've described, I had a possession of over 30 Mullards various kinds for the 12AU7's integrated/headphone and preamp's I have they all sound distinctively close to each other. 
    Baldwin organ tubes 12AU7 are made by Sylvania.
    The best Mullards are Holland and Blackburn plant, same two plants Amperexes come from.
    LOL, Telefunken's are not rolled off period that award goes to the English plant make Amperex's dark and laid back sounding, you must have a rebrand from another manufacturer, there is a reason they are the best amongst the dual triode family with a strong following out there, best 12AU7 based tube money can buy for sound is the ECC802S, made in West Germany. There lower "generic" range that go for $40-100 fitting the usual description of smooth ribbed plates and a D getter blow Genalex ECC82's out of the water (which are also good tubes) that go alot more. 
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