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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. Didhefocus
    He ships worldwide!
  2. UmustBKidn
    Read this comparison.
    Read this post, in this thread.
    Your profile doesn't indicate your location, but I think I saw something about you being in the UK. Visit the eBay version in the UK and pick yourself up a Mullard ECC82. Maybe a Telefunken. Brimar if you can find one. Siemens would also be nice. Skip the Russian and Chinese tubes, they are tinny and noisy in comparison to vintage tubes. Yes, that's just my opinion, but I stand firmly by that opinion.
    If money is an issue, then look into the 12AU7 variants, e.g. the 5963, 5814, 6189, etc. They are usually cheaper and in far greater supply.
  3. UmustBKidn
  4. UmustBKidn
    Grrrrr. Did not look closely at capacitor sizes when I ordered parts.
    Just had to order more capacitors.
    I guess I could have built another top cover. Or another bottom cover. But bleh, too much work.
    On the bright side, the Mosfets and the voltage regulators went in without much difficulty.
    Now back to the waiting game...
  5. mcandmar
    Let me guess, the two output caps are too tall?   Or you bought Elna Silmic II, they are always twice as along as anything else.
    For the time being bung the stock caps back in and give it a listening test, would be curious to hear your opinion on the better fets as the difference is significant. I assume you went to 510's?
  6. UmustBKidn
    Actually, they were too wide. I would have had to remove the 3.5mm input connector to fit one of them in, and the other would have sat at a 45 degree angle, propped up against one of the voltage regulators. Tall would not be a problem (I can drill a hole in the top cover), so I decided to order the taller caps, with a workable width.
    The power supply cap turned out to be something called a "snap in" variety. I was not familiar with this type of termination, and didn't notice it when I ordered them. So in place of wires, there are what looks like tabs, meant to connect to something on a circuit board. Phooey. I also noticed that I failed to order 105 degree parts, so that got updated too. I'll still have to drill out that hole too (the new part is several mm wider), but I don't care, so long as I can fit it on the board.
    I'm just trying to avoid the situation where I need to mount parts off the board. I have seen some curious configurations, but I guess I'm just not quite prepared to go that route yet. I'm still hoping to keep the top cover, and get away with drilling or widening holes for the caps. I am keeping the stock heat sinks because I'm using a small USB fan to cool the unit.
    My logic is, if I have to resort to a lot of customization, then I'm giving up and buying a Bottlehead Crack now [​IMG] Which I plan on doing at some point anyway.
    I also hope to document this process in a concise way and put all the lessons learned in one place, so anyone else can do this. So far what I've learned has had to come from several different websites; the parts lists are different, the opinions vary widely, and it kind of bugs me that I've spent as much time as I have, just trying to figure out what to do. My other goals with this is task are to prove whether or not it's really worth monkeying with one of these amps at all, and if so, to put a firm price on what it costs to do so (and not usurp the whole discussion for the purpose of turning it into a business).
    The original design of this circuit, from what I can tell, comes from this project on the DIY Audio Projects website. Also near as I can tell, that freely available design has spawned at least four commercial amps from four separate companies. I don't know if I would have tried making one of those instead, had I run across that first. In any case, this amp and these mods have surely benefit from much improvement and discussion over the past few years. So I won't be reinventing the wheel, just polishing the chrome a bit. Of course, there will be a comparison to my stock Bravo V2 when I'm done.
  7. mcandmar
    There was indeed a few variations (excuse the pun), and a few different manufacturers that produced variations, the Indeed G3 being the latest revision of the design. Its a fun little amp to experiment with, i certainly learnt a lot about different brands of capacitors and their individual sound, and same for the different types of transistors. It is deeply flawed though in that tubes running at that low a voltage are far from ideal and it runs hot enough to cook an egg. It can sound decent and be fun to listen to. It is in no way comparable to a Bottlehead Crack though, not even the same sport. But hey its cheap so have fun with it.
    The previous revision the Indeed G2 / Little-Bear P-1 can be picked up on eBay for ~£20 these days, at that kind of money everybody should have one [​IMG] 
  8. UmustBKidn
    Hah, yeah, I remember hearing a lot about the Indeed G3 when I first discovered this thread.
    Well, I am sad. I got the other caps this week, and went to put them in today. When I plugged everything in for a smoke check, I got no sound. [​IMG]
    At power on, there seemed to be an extra audible pop sound (from the headphones). I thought I heard some music briefly, while attempting to wiggle all the connections. But mostly silence, and some hum from the left channel.
    I think my last ditch attempt to salvage this project will be to give the circuit board a good cleaning. There is some flux spattered about. I may also try to re-flow the connections one more time. But at this point, I am depressed. Especially after putting this much thought into this thing. May also try a couple different cables.
    I guess I could try putting new semiconductors in, on the off chance that something was shorted. I don't know how fragile those things are. But I might just damage them again. Phooey.
    Curious that not even one side of the amp is working. Hmm.
    Well so assuming this amp is now a brick, I'm back to shopping for a new amp. I really don't want another little hybrid - I still have a working Bravo V2 at work. Indeed G3? Schiit Vali? Garage whatever? No, I think it will be time to take a step up.
    Assuming of course that I don't destroy the BHC with my soldering skills...
  9. Coolmeadow Kid
    Good evening.  My first post here.  I've read 30 pages so far...some very good information!  I'll keep reading this week as time permits.  I just ordered my Bravo V2 yesterday from Amazon.  Don't know if fleabay still has them or not, but I don't go there anymore, so it's a moot point.  I do have a couple questions.  Has anyone integrated a computer cooling fan to help with the heat build up?  I'm going to play with mounting one on top, with extensions to the 4 corner stanchions to clear the tube and cap that protrude through the factory top.  Second question is has anyone coupled this with a wireless to get headphones to the opposite side of the room without having extension cords to trip over?  I have a Nyrius NY-GS3200 5.8GHz 6 Channel Wireless Audio/Video Sender Transmitter & Receiver system coming also and I'll report on how that does.  I know it will not be hi fidelity, but hope that I can watch TV while the wife is teaching in an adjacent room. I can always bypass the wireless piece and plug my laptop into it to watch music videos. 
    I'll be using AKG K-240s with this set up.  Mostly listen to A Capella music, ie: Pentatonix.  I'm looking for ideas on a tube to roll that would have good bass, clear mids and highs and a good sound stage.  If A Capella music and bass seem to be directly opposed to each other to you, listen to some Pentatonix offerings and you'll understand my requirements.  Any help you can give would be greatly appreciated.  Now back to the 141 remaining pages!!!!  Jim.
  10. Coolmeadow Kid
    Got my Bravo 2 in Wed.  Just now getting it set up.  Definitely need a different tube.  Stock is all midrange and no bass, very few highs.  Looking for suggestions.  Letting it play with the headphones.  Both need to be broken in.  Sure wish I had my original AKG K240s from the middle 80s.  I think they sounded much better than the new ones, but that could be just old memories too.  Jim.
  11. Coolmeadow Kid
    Well, I mentioned the Nyrius NY-GS3200 5.8GHz 6 Channel Wireless Audio/Video Sender Transmitter & Receiver System I got to go with the Bravo V2.  I happy to report that it works great!  I'm sure it loses a little quality, but I can watch TV or videos from my laptop to the TV without bothering my wife.  This TV has a 3.5mm stereo audio out port that using a 3.5 to stereo RCA jacks attaches to the transmitter.  Then a short RCA patch cord to the Bravo unit and I'm in business.  Not bad for audio...certainly better than the cheap Panasonic on ear headphones I use with the laptop.  Just wanted to report this in case anyone else is looking for a similar solution.  Jim.
  12. razor5cl
    If your TV has some sort of digital output(optical maybe) you could get one of those cheap Fiio DACs that converts optical to RCA, then run that into your Bravo. That way you get a clean digital output rather than double amping.
  13. Coolmeadow Kid
    Yes, something like that would be ideal...and this TV does have the optical Toslink out.  The line level out I'm using is pre-amp as the level doesn't change with the built in TV volume and works even with the volume all the way down.  I think I could also do RCA out from my Yamaha RX-V667 HT receiver and do the same thing and use the built in Dac there.  But that would probably require the receiver to be turned on.  And since this RF unit is not going to be high quality anyway, I'm thinking I wouldn't gain anything.
    Now, if I was not using the RF unit to transmit the audio signal to the Bravo, the digital out would be the way to go.  Thanks for the note.  It is good information that I hadn't thought about.  Jim.
  14. Coolmeadow Kid
    I need some ideas on tubes.  What would be better if all testing shows to be equal.  Raytheon long black plates from 1959, or RCA 17mm gray plate clear tops from 1966?  Anyone with some help on what each will bring on the Bravo V2 vs the Stock tube?  I'd like a little more and clearer bass.  I'm using a newer set of AKG K240 headphones.   Thanks!  Jim.
  15. UmustBKidn
    Update: I decided to go back and re-solder each connection I made during my modifications, and do a good cleaning of the board with 99% alcohol. Lo and behold, that did the trick!
    Just for good measure, I finished up tonight with the crosstalk mod.
    I spent a good 2 hours listening to my modified V2. The setup was not optimal - used an ipod shuffle into a 3.5mm to RCA adapter to drive the bravo, and used my ATH M40's to listen. I had an old GE 5963 tube plugged in, so this was not the best I could do (no DAC on hand, and no better tubes).
    Oh My Gawd. Even with this setup, it sounds impressive. The improvement in the high end is amazing - not only is the amp clearer, the sound stage opened up and i could hear detail I had not heard before on this amp. The only disappointment was the bass sounded somewhat muddy. That could have been because of the lack of DAC (I'm not sure how hard I was driving it with the ipod), or perhaps these headphones (they are not the best cans). But hell, this is a world apart from the stock Bravo V2.
    Lesson learned: Cold Solder Joints are Evil. And one really must wash the board with 99% alcohol to get all the crud off. Either or both could have been the problem.
    I'm just glad it came back to life. Now I need to drill the top cover for the new, taller capacitors. I also need to perform the mod to alleviate the annoying "pop" that's happening at power up now. I don't want to blow out any headphones. Once that's done, it will be time for the Bravo Vs. Bravo review, with a proper DAC and some good tubes.
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