Originally Posted by igotyofire /img/forum/go_quote.gif Ok well ive been using this amp with my audio techinica phones which dont really require an amp necessarily, & i was wondering is this lil bravo tube amp sufficient for AKG701's or 600ohm Beyerdynamics, i guess what i want to know is what is the maximum ohms headphone i want to look at with this lil amp?
Tube amps like this one usually have no problem driving high impedance (300-600 ohm) phones. They often do that better than solid state amps can.
Originally Posted by igotyofire /img/forum/go_quote.gif Ok well ive been using this amp with my audio techinica phones which dont really require an amp necessarily, & i was wondering is this lil bravo tube amp sufficient for AKG701's or 600ohm Beyerdynamics, i guess what i want to know is what is the maximum ohms headphone i want to look at with this lil amp?
I'm using mine with AKG K701s, which still have under 100 hours on them. Too early to comment on the qualities of either, but I can turn the amp all the way up without any apparent/nasty distortion. This is the most powerful headphone amp I have at the moment, and it drives the AKGs to ear splitting levels. Even my 18V CMoy drive them quite well at comfortable listening volume, using AD8620 or AD843 (dual).
What I can say for sure is that the AKG K701 seems to need a lot of power, and it is probably the best headphone I have ever heard
I just received my Bravo today. Shipping time was about 3 1/2 weeks from time of order, however the wait was certainly worthwhile, as this is really a surprisingly nice-sounding amp!
I was not really expecting this level of performance at such a modest price. The amp was well packed and arrived in perfect condition. Out of the box with the stock tube it sounded very good. I have a couple of other tubes that work well in the Bravo...6DJ8 and Philips Miniwatt. I much prefer the sound of the Miniwatt in this amp as it really provides a very dynamic and realistic SQ.
There is certainly no shortage of power, as the Bravo effortlessly drives my AKG K340s to a far higher volume than I would ever need. It seems to be at its best when driving inefficient and/or high impedance cans. I believe that it would be overkill on some of my very sensitive IEMs.
I would certain recommend the Bravo for those looking for a budget hybrid amp that performs far above its price point!
Just got mine, excellent SQ with a Sylvania 6dj8 ($10 on ebay).
As a newbie, I have a question though..aside from the blue led light glowing when amp is on, shouldn't there also be a yellow/orange light from the tube itself?
Because this is a low-voltage tube hybrid, the heater won't be getting hot enough to have the tubes actually "glow". You may have a little bit of light depending on the tube, but nothing spectacular. There are lots of manufacturers who put LED's into these types of tubes to mimic tube glow, however. It's mainly an aesthetic thing.
While the Bravo obviously is a high-gain amp, I have not noticed any adverse effect on the highs as a result of the gain. Perhaps this is more a result of the OEM tube than gain. I am using a Philips Miniwatt tube with very good results. I have not made any changes using the trimmer pots yet.
I just turn down the volume to whatever is required for the phones I am using, and the highs sound quite natural.
I've read a few people saying they've used a philips miniwatt tube in this amp. I saw one listed for $10 on eBay, the model number was ecf80, will this one work? Or I saw several 6922 tubes for around the same price as well, would those work better? This amp is on it's way to me and I would like to order a different tube to try when I get it, but this is my first tube amp so I'm new to this.
Originally Posted by jageur272 /img/forum/go_quote.gif Because this is a low-voltage tube hybrid, the heater won't be getting hot enough to have the tubes actually "glow". You may have a little bit of light depending on the tube, but nothing spectacular. There are lots of manufacturers who put LED's into these types of tubes to mimic tube glow, however. It's mainly an aesthetic thing.
The heater is just as hot as any other circuit or it wouldn't work. The plate voltage is lower than any normal operating range for this tube which is about 90 volts or above, this is at 17. These tubes just don't glow much under any circumstances.
Originally Posted by derek800 /img/forum/go_quote.gif I've read a few people saying they've used a philips miniwatt tube in this amp. I saw one listed for $10 on eBay, the model number was ecf80, will this one work? Or I saw several 6922 tubes for around the same price as well, would those work better? This amp is on it's way to me and I would like to order a different tube to try when I get it, but this is my first tube amp so I'm new to this.
You need to get a tube that is a 6DJ8 direct replacement. These include 6DJ8, 6922, 7308, ECC88, E88CC and others like the 6N11 that it comes with. The 6922 and 7308 were premium tubes but that doesn't mean they sound better in your amp. The ECC88 tubes are a European designation.
Phillips Miniwatt is a brand of tube not a type. There were a huge number of brands and many manufacturers rebranded. So you could get a Phillips made tube labeled RCA for example. They changed over time so figuring out what is what is not simple.
So what do you do?
If you want to start cheap but decent and available there are a bunch of Sylvania 6DJ8, 6922 and 7308's with green lettering that are decent. Many are labeled Sylvania JAN 6922 and come in a white box with black lettering. The JAN stands for Joint Army Navy and was just stuff made for the military. (see the tubes in my Avatar).
Try to buy a tube that comes in the original box if you can.
Originally Posted by derek800 /img/forum/go_quote.gif I've read a few people saying they've used a philips miniwatt tube in this amp. I saw one listed for $10 on eBay, the model number was ecf80, will this one work? Or I saw several 6922 tubes for around the same price as well, would those work better? This amp is on it's way to me and I would like to order a different tube to try when I get it, but this is my first tube amp so I'm new to this.
ECF80 is a no go. Any 6dj8 or equivalent will work. European designation for a 6dj8 is ECC88 or 5358 Brit mil spec. A 6922 (E88CC or 2492 for Brit mil spec) is an "improved" 6dj8 with typically tighter tolerances and usually gold pins. A 7dj8 or PCC88 should work. I have a PCC88 miniwatt that sounds like heaven in my Indeed. Search for these types first and then select the brand. A tube with JAN on it is a US mil spec tube... look for 6922 or 7308 in these.
There are some great tube sites out there. Just Google 6dj8 or one of the other designations and start reading.
Sorry about double posting the same info as CPL593H...
Originally Posted by Judge Buff /img/forum/go_quote.gif ECF80 is a no go. Any 6dj8 or equivalent will work. European designation for a 6dj8 is ECC88 or 5358 Brit mil spec. A 6922 (E88CC or 2492 for Brit mil spec) is an "improved" 6dj8 with typically tighter tolerances and usually gold pins. A 7dj8 or PCC88 should work. I have a PCC88 miniwatt that sounds like heaven in my Indeed. Search for these types first and then select the brand. A tube with JAN on it is a US mil spec tube... look for 6922 or 7308 in these.
There are some great tube sites out there. Just Google 6dj8 or one of the other designations and start reading.
Sorry about double posting the same info as CPL593H...
Hey you added some stuff that I've wondered about, in particular the 7DJ8, I'm going to try one one of those.
Originally Posted by weibby /img/forum/go_quote.gif cool.
Looks like I can try to play around with these.
Edit: they're not listed anymore?
And it seems indeed is out for blood - $79usd...
Henry, the Ebay seller of the Bravo said that the amp would be available again when they found a suitable replacement tube, as the original NOS tube that was used is no longer available. He said it should likely be within a couple of weeks.
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