Question about tube amps (now with review of Bravo V3 )
Dec 19, 2013 at 12:38 PM Thread Starter Post #1 of 32

professorwiki

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Hi all,

I've browsed this forum for a long time and decided to join. I recently ordered a Bravo V3 headphone amp which has a tube amplifier. Exactly how hot do these things get? It's just a little amp with a single tube, but would it be okay to set it inside a large area in my entertainment center near other electronics or should I set it on top of the entertainment center so it can get more air flow? 

I ordered this to go with my new Sony MDR-V6s which I am LOVING so far, but wanted to get that "tube"  sound everyone talks about. I consider myself a bit of an audiophile, at least as far as I can afford (I'm a recent college graduate working a part time retail job to save for the GRE), so I'm looking forward to this, but I just would like to know any safety tips or tips to prolong the longevity of the tube in it (I can't afford to go order a bunch of different tubes to try at the moment). 

Thanks all!
 
Dec 19, 2013 at 1:31 PM Post #2 of 32
I had a different tube amp, the Little Dot MKIII, and the tubes themselves would get very hot to the touch (like a lightbulb), but it didn't heat up the air around it. As long as your entertainment center is open (i.e. not a closed cabinet), you should be fine. If it wouldn't be difficult to put the amp on the top of your entertainment center, that would probably be best, but it shouldn't make that much difference as long as it's not totally enclosed. 
 
Dec 19, 2013 at 1:32 PM Post #3 of 32
  Hi all,

I've browsed this forum for a long time and decided to join. I recently ordered a Bravo V3 headphone amp which has a tube amplifier. Exactly how hot do these things get? It's just a little amp with a single tube, but would it be okay to set it inside a large area in my entertainment center near other electronics or should I set it on top of the entertainment center so it can get more air flow? 

I ordered this to go with my new Sony MDR-V6s which I am LOVING so far, but wanted to get that "tube"  sound everyone talks about. I consider myself a bit of an audiophile, at least as far as I can afford (I'm a recent college graduate working a part time retail job to save for the GRE), so I'm looking forward to this, but I just would like to know any safety tips or tips to prolong the longevity of the tube in it (I can't afford to go order a bunch of different tubes to try at the moment). 

Thanks all!

The Bravo isn't an ideal tube to start with unless you plan on moddifying it. As far as maintence goes, I owned an Indeed G3 a VERY simmilar product. Best to keep it away from dust, pets or children. As you can see the tube amp is no enclosed so there is a chance that physical contaiments can get onto the PCB board which can cause harm to the amplifier 
 
additionally you may need to balance the Bias pots of the amplifier, which reqiures that you use a small screw driver. As far as heat goes it does get hot. so I would not set it atop of anything.
 
My  best advice for you is if you can return the BRavo do so, additionally if you can afford to. Get the Schiit Vali which is $137 dollars shipped. The vali runs cooler and is less prone contamination, additionally the Vali does not need to be re balanced
 
How ever if you cannot return your Bravo. Just try to be careful around it! Tubes are breakable and since the PCB board is open be careful not to allow anything side of it.
 
What ever you do though just enjoy the amp! I liked how my Indeed G3 sounded. An truth be told, while adjusting the bias takes time it is a little fun some time 
 
Dec 19, 2013 at 2:00 PM Post #4 of 32
Thanks for the reply.

I got the V3 for 75 dollars on eBay, which was a good deal, so I don't know if I'll want to return it. I'm not concerned about dust, I can easily clean out any dust with a can of air. I was more concerned about it damaging another component from the heat if it was set on top of something. Exactly about how hot do these things get, 140 F or so? 

As for it falling, that would be unlikely since my cat is not allowed in my room without supervision and the MRD-V6s have a long cable so there wouldn't be much of a change of me tugging it off the shelf.

However, can anyone explain the biasing and how to do that? I don't know a whole lot about circuit boards, etc. 
 
Dec 19, 2013 at 2:08 PM Post #5 of 32
  Thanks for the reply.

I got the V3 for 75 dollars on eBay, which was a good deal, so I don't know if I'll want to return it. I'm not concerned about dust, I can easily clean out any dust with a can of air. I was more concerned about it damaging another component from the heat if it was set on top of something. Exactly about how hot do these things get, 140 F or so? 

As for it falling, that would be unlikely since my cat is not allowed in my room without supervision and the MRD-V6s have a long cable so there wouldn't be much of a change of me tugging it off the shelf.

However, can anyone explain the biasing and how to do that? I don't know a whole lot about circuit boards, etc. 

It may not need it but
 
for my Indeed G3, the tube amp has voltage running through it, the bias controls the amount of voltage going through the amp If it's not balanced, as in balanced volts going into the tube for the left and right channels you may wind up having distortion. More sound on the left, or the right ect.... My indeed G3 needed manual Bias adjustments. Check and see if your V3 requires the same 
 
Dec 20, 2013 at 12:41 AM Post #7 of 32
I have a bravo V3 as well!!!! :D I really like it & it didn't require any balancing. left & right sounds equal to me, but then again I don't have golden ears hahah
 
Dec 20, 2013 at 2:43 AM Post #8 of 32
  Thanks for the reply.

I got the V3 for 75 dollars on eBay, which was a good deal, so I don't know if I'll want to return it. I'm not concerned about dust, I can easily clean out any dust with a can of air. I was more concerned about it damaging another component from the heat if it was set on top of something. Exactly about how hot do these things get, 140 F or so? 

As for it falling, that would be unlikely since my cat is not allowed in my room without supervision and the MRD-V6s have a long cable so there wouldn't be much of a change of me tugging it off the shelf.

However, can anyone explain the biasing and how to do that? I don't know a whole lot about circuit boards, etc. 

The Bravo V3 does come with two voltage adjustment settings, one for each channel.
For best audio quality you want the two channels to match voltage and set as high as possible.
(For my EH6992 Tube amplifier, 12 to 13 volts was recommended, 12 volt might be safer)
You can use a DT830 Digital Multimeter ($10) for test the voltage levels
Then use a philipshead screwdriver to make adjusts.
Use the screwdriver on those two little orange "screw" things right in front of the tube.
You want to test and adjust the voltage after the tube amplifier has warmed up, which might take several minutes.
The factory (or workshop?) where the Bravo V3 was built may or may not have taken the time to fully adjust the V3's voltage, before shipping it out.
 
You might find detailed directions on the website Rockgrotto, in the head amp threads.
http://rockgrotto.proboards.com/board/8/headphone-amplifier-forum
 
Dec 20, 2013 at 3:01 AM Post #9 of 32
  The Bravo V3 does come with two voltage adjustment settings, one for each channel.
For best audio quality you want the two channels to match voltage and set as high as possible.
(For my EH6992 Tube amplifier, 12 to 13 volts was recommended, 12 volt might be safer)
You can use a DT830 Digital Multimeter ($10) for test the voltage levels
Then use a philipshead screwdriver to make adjusts.
Use the screwdriver on those two little orange "screw" things right in front of the tube.
You want to test and adjust the voltage after the tube amplifier has warmed up, which might take several minutes.
The factory (or workshop?) where the Bravo V3 was built may or may not have taken the time to fully adjust the V3's voltage, before shipping it out.
 
You might find detailed directions on the website Rockgrotto, in the head amp threads.
http://rockgrotto.proboards.com/board/8/headphone-amplifier-forum

nvm hahah. i figured it out :p
 
Dec 20, 2013 at 8:00 AM Post #10 of 32
  The Bravo V3 does come with two voltage adjustment settings, one for each channel.
For best audio quality you want the two channels to match voltage and set as high as possible.
(For my EH6992 Tube amplifier, 12 to 13 volts was recommended, 12 volt might be safer)
You can use a DT830 Digital Multimeter ($10) for test the voltage levels
Then use a philipshead screwdriver to make adjusts.
Use the screwdriver on those two little orange "screw" things right in front of the tube.
You want to test and adjust the voltage after the tube amplifier has warmed up, which might take several minutes.
The factory (or workshop?) where the Bravo V3 was built may or may not have taken the time to fully adjust the V3's voltage, before shipping it out.
 
You might find detailed directions on the website Rockgrotto, in the head amp threads.
http://rockgrotto.proboards.com/board/8/headphone-amplifier-forum

 
 
  nvm hahah. i figured it out :p

Yea... have fun with that :D my indeed G3 needed voltage adjustments about every 8 listening hours... I was lucky enough to have two metal leads from the Pots on the side of the amp, so getting a meaure was easy
 
but I highly suggest you get some aligator clips, so you don't have to hold the Multi Meter with one hand and attempt to adjust the bais with the other... it helps to have two hands to get those 2 volts perfectly matched! 
 
Dec 20, 2013 at 8:24 AM Post #11 of 32
 
Yea... have fun with that :D my indeed G3 needed voltage adjustments about every 8 listening hours... I was lucky enough to have two metal leads from the Pots on the side of the amp, so getting a meaure was easy
 
but I highly suggest you get some aligator clips, so you don't have to hold the Multi Meter with one hand and attempt to adjust the bais with the other... it helps to have two hands to get those 2 volts perfectly matched! 

Quick question: why did your G3 need voltage adjustments every 8 hours? I've been using my Bravo V3 amp for almost a week now & I haven't noticed any audio discrepancies that would lead me to wanting to adjust the voltage. left & right sound levels sound balanced after doing a quick test tone listen. what is it that you hear that prompts you to adjust the voltage?
 
Dec 20, 2013 at 8:39 AM Post #12 of 32
  Quick question: why did your G3 need voltage adjustments every 8 hours? I've been using my Bravo V3 amp for almost a week now & I haven't noticed any audio discrepancies that would lead me to wanting to adjust the voltage. left & right sound levels sound balanced after doing a quick test tone listen. what is it that you hear that prompts you to adjust the voltage?

im balance, or a little lack of bass on one channel
 
it MAY be that with my INdeed G3 the Bass Boost feature that it had [which in addition to boosting bass actually boosted the voltage running through the amp] was causing an unbalnce in teh voltage, I'm happy to hear your Bravo does not need the same treatment :3. ANd yea it was the Bass boost, it increased voltage by about 2.5 volts on each channel. When I would turn the boost off  it would drop about 2.34-2.56 :/ so imagine turning that on and off 3 or four times a day depending on when I wanted MO bass for my music and when I wanted un boosted bass, that cuased the bais to get wonky... but man that was still a FUN little amp! 
 
Dec 20, 2013 at 7:44 PM Post #13 of 32
  im balance, or a little lack of bass on one channel
 
it MAY be that with my INdeed G3 the Bass Boost feature that it had [which in addition to boosting bass actually boosted the voltage running through the amp] was causing an unbalnce in teh voltage, I'm happy to hear your Bravo does not need the same treatment :3. ANd yea it was the Bass boost, it increased voltage by about 2.5 volts on each channel. When I would turn the boost off  it would drop about 2.34-2.56 :/ so imagine turning that on and off 3 or four times a day depending on when I wanted MO bass for my music and when I wanted un boosted bass, that cuased the bais to get wonky... but man that was still a FUN little amp! 

mmm... yea, i can't say i've experienced that problem. my bravo amp has a 3 band eq (so there is a bass boost feature), but i never use it. i would software EQ & if i was EQ-ing anything on my HE400 is would be bringing the treble down a lil hahah.
 
Dec 20, 2013 at 9:57 PM Post #14 of 32
Yeah, I think if I use the EQ at all it will probably be to tame the treble on the MDR-V6s a bit. I'll have to see how it sounds flat with the tube amp. 

I know my LP-120 turntable with the ART DJ preamp already sounds pretty sweet when I use my Fiio E5, so I'm really hoping the tube is at least a marginally noticeable improvement.
 
Dec 20, 2013 at 11:17 PM Post #15 of 32
Just an FYI, but it's a problem with single-tube amps.  To get stereo, single tube amps use one triode of a dual-triode tube for each channel.  Trouble is, dual-triode tubes rarely test out equal between the triodes.  Some are way off.  A manual bias adjustment will allow you to "center" the soundstage with unequal triode output, but if one triode truly has a higher output, the peaks will always sound louder on that channel, even if the background has been centered with the bias adjustment.
 
It's why you see most tube amplifiers with one tube per channel.  Almost all of those tubes are dual-triode tubes, but the circuit ties the two triodes in parallel, effectively averaging the output between the two triodes.  This exponentially increases your chance of matching two tubes for the two channels, because all you have to match is the average combined output of the tubes' two triodes.
 

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