Bravo Audio V1 Review - The Little Headphone Amp That Could
May 28, 2012 at 2:02 PM Thread Starter Post #1 of 16

kalinov

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Part I: Bravo Audio V1

 
[size=medium] When I was 14 I remember listening to the Lion King soundtrack CD on a Magnavox Hi Fi system.  I still remember how emotional the music was.  A month ago I remembered that experience and I got my CD out.  I don’t have the Hi Fi system anymore so I plucked it in my PC.  And I listened to it again.  But there wasn’t any of that emotional energy that I felt before.  It was just lifeless.  It sounded like cheap colorful plastic much like contemporary pop music from the post-Michael Jackson era. So I started thinking - was this happening because I was grown up and have left childish things behind me?  Or was there another reason? I had to find out.

 So I started on my quest to find out if I still had a soul.  Looking around the internet and reading a lot about headphone amps I discovered that tube amps are one of the keys to a full musical experience.  But it was expensive.  One of the cheapest quality tube amps, the Little Dot MK III, costs $300.  I can afford that but I wouldn’t give that much money just so I can “try out” if it works.

 Life was gray until a month ago when I stumbled onto something when looking through Ebay - The Bravo Audio.  A headphone tube amp which sells for $70.  A real life tube amp for money which I was willing to pay.  And that I would pay to see what the fuss was all about.  Maybe it would bring back even a glimmer of the life in my music.

 Five days later I received a little box.  I got it out.  A pretty piece of acrylic plastic, some electronic elements and a tube sticking out.  For a desktop gadget I actually like how it looks:
[/size]

 

 
[size=medium]At first it was hard to believe that this little DIY-looking thing would make a difference in the sound.  I got the RCA cables and hooked it up.  I am using my internal PC sound card.  My headphones are Canyon CNR-HS10.  I also read that tube amps should be left to “burn in”.  So I did.  I made a song list to loop over during the night and left it on repeat.

After two days of that I went through some music and games to compare before and after.  Here’s the list:

Music: Pink Floyd, Blind Guardian, Leonard Cohen, Jonny Cash, Louis Armstrong, Sabaton, Enigma, Sphongle, Sabaton, Led Zeppelin and some classical.  And of course the Lion King.

Game music: Diablo I and II, Fallout, King’s Bounty: Armoured Princess.

How does it compare?  The before sound is weak, veiled, impotent.  It’s as if it’s afraid to come out.

And with it?  Think of this scene from the Pixar movie Rattatui - http://www.youtube.com/watch?v=Yyah49_Oz78.  The amp gives music strength, it brings it to life and makes it colorful.  With it music has punch, it's vibrant and rich.

I am extremely happy with this little purchase.  It brought life back to my music.  It’s a whole new world of discovery.
[/size]


 

[size=medium]Part II: When Bravo met Sylvania[/size]


[size=medium]One interesting aspect of the Bravo Audio V2 is that you can swap out the tube. Just take out the old one and pop in a new one. It's that easy. Some people claim that the tube model itself is responsible for 50% of the whole experience.  Upon further research it turned out that the Sylvania tube is the best bang for the buck.  And since I had no intention of shelling out $500 for a tube, I had to go for bang for the buck.  I found a tube which is cheap, yet is given extremely good reviews - the JAN Sylvania 6922.

A few days later and here they are cradled together - Bravo Audio the amp and Sylvania the tube:
[/size]

 

 
[size=medium]At first there was no difference in the audio.  It was actually worse - it sounded watery. Maybe it was my non-trained ears.  I felt ripped off.  So again I burned it in overnight.[/size]

Now I hear the difference.  The highs are crystal, pristine yet disciplined. The mids are like purple velvet.  And the bass is controlled pounding, like a lion roaring in front of you.

If getting the Bravo amp was like going to a live concert performance as opposed to listening to a recording at home, then having the Sylvania tube is like going to a symphony - everything is fuller, richer and more encompassing.  It sounds complete and there are no holes.

I didn’t think this would happen, but for the second time I am going through my music collection with renewed interest.

There’s just one thing missing....  When Led Zeppelin’s Stairway to Heaven starts I can hear a low hum.  I also have a feeling that some of the potential of the sound is still missing and the Bravo has yet more to show me.  For that, however, I would need to go to the Source.  I need to change my sound card and bring my beginner audio distiller project to relative completeness. When that happens I'll share the experience - "Part III: Bravo and Sylvania sitting by the HRT Streamer II".

 
May 28, 2012 at 8:43 PM Post #2 of 16

PurpleAngel

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Invest in a digital multi-meter (DT830, $7), with it you can fine tune the balance and the voltage output of the Bravo.
Directions are in a forum thread at the website Rockgrotto.
 
Jun 2, 2012 at 6:00 AM Post #4 of 16

kalinov

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PurpleAngel, I fine tuned the voltage after looking at the Rockgrotto forum.  Interestingly, the balanced values on my unit are ~14.5V.  If I increase one to 16.5V, the other falls.  I presume this is OK.  What's important is probably the balance.  Could this be because of the custom vacuum tube I have installed, or could it be something else?
 
Jun 2, 2012 at 11:26 AM Post #5 of 16

PurpleAngel

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Quote:
PurpleAngel, I fine tuned the voltage after looking at the Rockgrotto forum.  Interestingly, the balanced values on my unit are ~14.5V.  If I increase one to 16.5V, the other falls.  I presume this is OK.  What's important is probably the balance.  Could this be because of the custom vacuum tube I have installed, or could it be something else?

I thought that balanced at 13.5 v was recomended, so you might be going a little too high on one channel.
 
Jun 14, 2012 at 12:33 AM Post #7 of 16

pokee1016

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Hey, I just found this thread. I have the 12au7 bravo. I've don a lot of mods. I'm experienced- used to design commercial audio tube amps- but there are some easy tweaks you can make without doing too much surgery. The biggest difference was- and always is- the power supply which isn't hard to do if you find a linear supply preferably regulated. The one supplied is switching and switching power supplies do not belong in audio. Period. Don't listen to anyone who tells you otherwise. When you find one, you just need to match or swap the dc connector (watch the polarity!)  The second thing you want to do is replace the IRF630 mosfets with IRL530 which will give you better high end extension and more headroom (big improvement) . Those two things alone will transform the sound. Just my 5 cents.
 
Jun 15, 2012 at 9:51 AM Post #8 of 16

kalinov

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Hey pokee1016,
 
Hmmm interesting...I remember reading about the power supply mod but didn't think it would make a difference.  When I was a kid I used to tinker a lot with electronics (I've done many autopsies on still living household devices) so I'll try these mods.  It'll be interesting to see how far I can take the quality of the sound output of this little gem amp without touching the internal sound card.  The HRT Streamer II will take the place as the source at some point, but not right now.
 
So, from what I understand the power supply and the mosfets are the most important mods to do first.  What kind of difference would the power supply make?  Will it get rid of the bottom hum I hear when I turn up the volume?  Or is that from the internal sound card? I'll go to an electronics store and look for a linear supply.  I hope they know what that is :). I guess I'll have to find one with matching volts and ampers to the current power supply, correct?
 
On another note, while digging into ways to get the "perfect" audio, I read that electrostatic speakers/headphones are the diamonds of audio presentation.  I also see they cost as much as a small car. I'm thinking that at some point I'll try doing DIY electrostatic headphones.  Don't know if I could reuse the Bravo Audio amp for that as well.  In your experience, would that be possible for a hobby project for someone like me who used to tinker with electronics and circuit boards but is no professional?
 
Jun 15, 2012 at 2:03 PM Post #9 of 16

PurpleAngel

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Quote:
Hey, I just found this thread. I have the 12au7 bravo. I've don a lot of mods. I'm experienced- used to design commercial audio tube amps- but there are some easy tweaks you can make without doing too much surgery. The biggest difference was- and always is- the power supply which isn't hard to do if you find a linear supply preferably regulated. The one supplied is switching and switching power supplies do not belong in audio. Period. Don't listen to anyone who tells you otherwise. When you find one, you just need to match or swap the dc connector (watch the polarity!)  The second thing you want to do is replace the IRF630 mosfets with IRL530 which will give you better high end extension and more headroom (big improvement) . Those two things alone will transform the sound. Just my 5 cents.

I believe the Indeed brand switched to IRL530
 
Aug 11, 2012 at 12:18 PM Post #10 of 16

kalinov

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Quote:
Hey, I just found this thread. I have the 12au7 bravo. I've don a lot of mods. I'm experienced- used to design commercial audio tube amps- but there are some easy tweaks you can make without doing too much surgery. The biggest difference was- and always is- the power supply which isn't hard to do if you find a linear supply preferably regulated. The one supplied is switching and switching power supplies do not belong in audio. Period. Don't listen to anyone who tells you otherwise. When you find one, you just need to match or swap the dc connector (watch the polarity!)  The second thing you want to do is replace the IRF630 mosfets with IRL530 which will give you better high end extension and more headroom (big improvement) . Those two things alone will transform the sound. Just my 5 cents.

 
Thanks a lot for the advice, pokee1016!
 
Right now I'm looking for a linear power supply.  I found one which gives 22-26V (I'm thinking the Bravo Audio needs 24V, correct?) and 2.25A.  Will this do?  It seems the best option that I've discovered which won't break the bank. I wasn't aware how expensive quality power supplies are!
 
I'll be changing the mofsets to IRL530 as per your suggestion.
 
I've also finally reached the point where I'm going to order the HRT Music Streamer II.
 
The review will be updated when those things happen.
 
All in all, this little amp turned out to be a great buy.
 
Aug 16, 2012 at 12:12 AM Post #11 of 16

kalinov

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Quote:
Hey, I just found this thread. I have the 12au7 bravo. I've don a lot of mods. I'm experienced- used to design commercial audio tube amps- but there are some easy tweaks you can make without doing too much surgery. The biggest difference was- and always is- the power supply which isn't hard to do if you find a linear supply preferably regulated. The one supplied is switching and switching power supplies do not belong in audio. Period. Don't listen to anyone who tells you otherwise. When you find one, you just need to match or swap the dc connector (watch the polarity!)  The second thing you want to do is replace the IRF630 mosfets with IRL530 which will give you better high end extension and more headroom (big improvement) . Those two things alone will transform the sound. Just my 5 cents.

Hey, pokee1016, the store I'm looking at doesn't have IRL 530, but they do have IRL 540.  Will it do?
 
Nov 27, 2014 at 1:25 AM Post #12 of 16

igotyofire

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Thanks a lot for the advice, pokee1016!
 
Right now I'm looking for a linear power supply.  I found one which gives 22-26V (I'm thinking the Bravo Audio needs 24V, correct?) and 2.25A.  Will this do?  It seems the best option that I've discovered which won't break the bank. I wasn't aware how expensive quality power supplies are!
 

 
 
Anyone have a power supply suggestion for this amp?
 
Jul 26, 2015 at 11:37 AM Post #13 of 16

tubyfran

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i have this unit and actually this unit will sound relatively poor compared to a similiar tube amp that i built myself.
lots of stuff in this amp degrades sound ultimately gives a poorer sound quality.the design that i done with 12au7 surpasses many 300 dollar and above tube amps.
key factors are component quality and  power grounding techniques.
i found that the RCA cleartops  were the best sounding ..GE and Sylvanias coming 2nd .
The euro tubes sound great too but are hard to find.
power supply needs a good regulated one with at least 10va transformer.
 
Jun 15, 2017 at 7:35 PM Post #15 of 16

Florin Andrei

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I've used this amp for a number of years at work. It may not be the fanciest amp, but it looks cool, and it's decent enough with a pair of noise-cancelling phones, just for blocking out noise.

Except recently it stopped working. All I get is a buzzing noise in both channels, as if it was self-oscillating at a few hundred Hz.

When I have an afternoon to spare, I'll open it up and attempt to do some measurements (voltages, etc). But until then I have this mystery on my mind: it's a little odd that it's buzzing in both channels at once. I would expect only one channel to die, unless the defect is in a shared component, and only the tube is shared.

I've checked the tube heater filament and it's measuring around 4 ohm, so I don't think it's burned out. The tube is an EH6922.

Does this ring a bell to y'all?
 
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