"Hello ebayuser, Don't worry, I will test and send you a new one. But I am sorry you may wait a few more days for its shipping time. Sorry again.
Best regards, Hans"
So...sounds like I will have a working unit in another month or two.
Originally Posted by Judge Buff /img/forum/go_quote.gif X2 but I have really only needed to tweak the pots twice in all of the tube rolling I've done. I had to do it when I removed the crappy 6N11 stock tube and put in a PCC. When I switched to 6dj8s/6922s, I did a little tweaking to make the sound presentation "balance-out" in the phones. I couldn't tell you what pot did what though... The pots are really sensitive and they aren't precise at all.
I think that the older valves are more standardized and were manufactured to tighter tolerances than the Russian and Chinese tubes are now. There's just a bunch of retrotechno junk out there. I also wouldn't buy a JJ/Tesla on a dare, from what I'm reading. Those rebranded remakes are expensive junk, too.
The pots should do the same thing on the left and right channel. They should set the bias on the cathode of the 6dj8 on pins 3 and 8.
Originally Posted by CPL593H /img/forum/go_quote.gif Here's the explanation for what I'm quite certain is hard disk noise. I'm using a Xonar DX sound card with back panel and front panel output. I didn't pay any attention to the routing of the wire for the front panel, just used it as it came with the computer case.
So I hooked the Bravo amp to the front panel and heard very audible noise that seemed to be correlated with hard drive operations. (the front panel wire runs through the HD bay). The sound went away but I could get it to come back by doing something like opening Photoshop. So I hooked the amp up to the back panel jack and zero noise. I didn't worry about it after that I guess I could shield or reroute the wire. I suppose it could be associated with something else in the case, any ideas?
I sometimes gets noise interferrence from the wireless. If I turn off the wireless, it goes away and it is very dependant upon positioning of gear. also most often with tubes vs SS
Originally Posted by CPL593H /img/forum/go_quote.gif The pots should do the same thing on the left and right channel. They should set the bias on the cathode of the 6dj8 on pins 3 and 8.
I guess that's why they appear to be in the same position, now.
Originally Posted by Judge Buff /img/forum/go_quote.gif I guess that's why they appear to be in the same position, now.
That's good. When I take the amp apart to replace the coupling caps and the flaky power jack I'll measure the bias voltage on the stock tube and a couple 6DJ8s, ones that work good an a couple that are marginal. I think the marginal ones might work with a little more bias.
Originally Posted by HiFlight /img/forum/go_quote.gif About the best upgrade you can make for the Bravo is to replace the cheap 1A switching power supply with a better quality 2-2.5A switcher or regulated supply. We did an A-B test with mine a recent mini-meet and the better quality 2A supply sounded much better.
Using a larger power supply will not harm the amp.
How does a larger power supply improve the sound in this amp? Does the 1A power supply limit the sound or power? I did notice that the indeed amp comes with a 2A unit. I will buy a larger power supply if the improvement is significant. Do you guys know the dimensions for the round power supply connector?
I am about 30 hours on the Bravo and the pinched waist amperex now and the sound is improving. I was listening to Spanish Harlem by Rebecca Pidgeon and she sounds amazing.
Originally Posted by 22B /img/forum/go_quote.gif How does a larger power supply improve the sound in this amp? Does the 1A power supply limit the sound or power? I did notice that the indeed amp comes with a 2A unit. I will buy a larger power supply if the improvement is significant. Do you guys know the dimensions for the round power supply connector?
I am about 30 hours on the Bravo and the pinched waist amperex now and the sound is improving. I was listening to Spanish Harlem by Rebecca Pidgeon and she sounds amazing.
im after one in hopes of finding somthing that doesn't short out on me, heh. It seems their might be some reliability issues with this one. Altho mine still works...should be no reason for intermittent behavior
Originally Posted by CPL593H /img/forum/go_quote.gif Here's the explanation for what I'm quite certain is hard disk noise. I'm using a Xonar DX sound card with back panel and front panel output. I didn't pay any attention to the routing of the wire for the front panel, just used it as it came with the computer case.
So I hooked the Bravo amp to the front panel and heard very audible noise that seemed to be correlated with hard drive operations. (the front panel wire runs through the HD bay). The sound went away but I could get it to come back by doing something like opening Photoshop. So I hooked the amp up to the back panel jack and zero noise. I didn't worry about it after that I guess I could shield or reroute the wire. I suppose it could be associated with something else in the case, any ideas?
Ahhh, yeah, I had the same issue,
I believe it is caused because the front port is on the same bus (I think?) as the lead to the HDD's (it is also on the same signal channel as USB ports)
This means that when you draw power off any component on the front panel, signal noise is introduced, so it is the frontport/bus that is creating the actual noise, but the hdd spinning and PS accessing the frontport briefly while processing that makes the noise your referring to when using PS. Try plugging in a USB Thumb Drive, and your headphones into the front port, and then copying a 20 meg file over to your harddrive, you'll see what I mean, it's the bus, not the HDD's themselves that cause the actual signal noise. (this is why you get no noise in back, because there is no signal overlap for your audio out of dedicated sound card, nothing else is drawing on that signal for other uses....)
This make sense? Other than interconnects, I just can't see a reason why HDD's would interfere with amp noise, other than if using a bad signal (1/8th jack out of frontpanel) as source. (which is why I run my DAC out of back of card, then to the Amp, and was concerned about the presence of hum/hiss in this scenario, as when I plug the headphones straight into the Soundcard I get no hum/hiss at all)
This clarify things perhaps? (or am I totally off track... try the USB transfer though, you'll see what I mean)
Originally Posted by 22B /img/forum/go_quote.gif How does a larger power supply improve the sound in this amp? Does the 1A power supply limit the sound or power? I did notice that the indeed amp comes with a 2A unit. I will buy a larger power supply if the improvement is significant. Do you guys know the dimensions for the round power supply connector?
I am about 30 hours on the Bravo and the pinched waist amperex now and the sound is improving. I was listening to Spanish Harlem by Rebecca Pidgeon and she sounds amazing.
The improvement is significant and easy to hear. The bass is deeper/tighter/thicker plus there is better definition and clarity.
I forgot to state that thanks to HiFlight I was able to listen to this little amp and I was very impressed by it. So much so I started looking to buy one, however at $90 plus S&H is a pretty steep increase in price.
Originally Posted by 22B /img/forum/go_quote.gif How does a larger power supply improve the sound in this amp? Does the 1A power supply limit the sound or power? I did notice that the indeed amp comes with a 2A unit. I will buy a larger power supply if the improvement is significant. Do you guys know the dimensions for the round power supply connector?
I am about 30 hours on the Bravo and the pinched waist amperex now and the sound is improving. I was listening to Spanish Harlem by Rebecca Pidgeon and she sounds amazing.
It's my opinion that the 1A switcher does not provide enough current for transients especially low bass. Using a 2A supply noticeably improve the bass impact and resulted in a considerably cleaner overall sound.
Considering the current draw of the FETs and filament heater, I believe the 1A is somewhat overtaxed, and does not allow the Bravo to show its full potential.
Just got one of these amps myself; fairly quick shipping and no problems with US customs. Putting it through its paces, have run ATH-M50's, K270 Playback's and PX100's through the Bravo and they all have benefited from it; the sound is great. No power supply or component issues either (fingers crossed!). So far I'm pretty impressed with this little amp, especially for what I paid for it. A little dismayed to see that some folks are having problems with them and the price on eBay jumped $30 from what they were. Glad to hear the vendor is stand-up when it comes to resolving issues.
However, wanted to do some rolling so I replaced the stock 6N11 tube with a Sylvania 6DJ8 and immediately noticed that the the amp went from being tomb-like quiet while turning the volume knob (and no sound going through it) to having a static-y, dirty-pot kind of sound in the left channel while adjusting the volume. Also, the bass sounds a little "flabby" in the right channel. Strange as it doesn't happen on the 6N11 but does on both of the 6DJ8's I have. Any suggestions on what it might be? Maybe the bias pots need adjusting? Thanks for any help!
Originally Posted by D.Proper /img/forum/go_quote.gif Just got one of these amps myself; fairly quick shipping and no problems with US customs. Putting it through its paces, have run ATH-M50's, K270 Playback's and PX100's through the Bravo and they all have benefited from it; the sound is great. No power supply or component issues either (fingers crossed!). So far I'm pretty impressed with this little amp, especially for what I paid for it. A little dismayed to see that some folks are having problems with them and the price on eBay jumped $30 from what they were. Glad to hear the vendor is stand-up when it comes to resolving issues.
However, wanted to do some rolling so I replaced the stock 6N11 tube with a Sylvania 6DJ8 and immediately noticed that the the amp went from being tomb-like quiet while turning the volume knob (and no sound going through it) to having a static-y, dirty-pot kind of sound in the left channel while adjusting the volume. Also, the bass sounds a little "flabby" in the right channel. Strange as it doesn't happen on the 6N11 but does on both of the 6DJ8's I have. Any suggestions on what it might be? Maybe the bias pots need adjusting? Thanks for any help!
The bias was set for the 6N11. Typically, the 6DJ8 runs at a higher plate voltage, so in effect, your bias is now low and likely not even running Class A at this point. I tried several other quality tubes, but found that the best sound was using the stock 6N11. I have not reset the bias for any of the other tubes. Perhaps in the future, I will try putting the amp on my test equipment and making some changes, but for now, I will just continue to use the 6N11.
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