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Post by PinkFloyd on Feb 4, 2010 1:49:28 GMT
By the way Peter, great to have you Far East guys online at last  Pinkie. |
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Post by gomez on Feb 4, 2010 11:50:26 GMT
Hi Mike Could you do me a favour & check the bravo for hiss ? Like I explained before I am getting background hiss even without a source connected & with the volume right down. I emailed Henry who was very quick to reply  he seems to think it may be caused by a faulty psu, he said to try to use another 24v 1 amp psu to see if it fixes the problem, however I don't think I have got anything like that hanging around. The psu does make a noise when the amp is off but the noise stops when you power the amp on ? So if you could check yours it may help find the problem  |
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Post by PinkFloyd on Feb 4, 2010 15:18:00 GMT
Hi Mike Could you do me a favour & check the bravo for hiss ? Like I explained before I am getting background hiss even without a source connected & with the volume right down. I emailed Henry who was very quick to reply he seems to think it may be caused by a faulty psu, he said to try to use another 24v 1 amp psu to see if it fixes the problem, however I don't think I have got anything like that hanging around. The psu does make a noise when the amp is off but the noise stops when you power the amp on ? So if you could check yours it may help find the problem Hi Gomez, Nope, no hiss on mine. It could also be the valve, do you have a 6922 / E88CC you could pop in? Mike. |
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Post by gomez on Feb 4, 2010 15:20:40 GMT
Hi Gomez, Nope, no hiss on mine. It could also be the valve, do you have a 6922 / E88CC you could pop in? Mike.[/quote] Nah got no valves at all mate New to this old technology  Does you psu make a noise till the amp is on ? |
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Post by Deleted on Feb 4, 2010 17:45:58 GMT
My Bravo Amp arrived this morning, had it running for 6hrs, being fed by my Ipod classic, Sendstation port adapter, connected to Amp via Chord 3.5 to twin phono socket lead. My observations are as follows:- Nicely packaged no frills, but arrived undamaged. After 6hrs continual running, the heat sinks do get very hot, and the PSU also gets quiet warm. No Hiss at any level. Extremely delicate touch required on volume control, off to 9oclock on the dial is all the volume you would need with the 681`s ( unless your deaf). The sound is quite remarkable for such a small Amp, loads of nice tight detailed Bass, very detailed mid and top end, very easy to listen to. Amp is nicely finished considering its price. could certainly use some proper feet instead of sliding around on its Caphead assembly screws, some nicely turned feet that would also raise the unit perhaps 20mm or so, which in turn would also help in the cooling department, will be made as soon as possible. All in all a lovely little amp, time will tell with regard to reliability of course, but for now i am a happy Bunny, £63 well spent  |
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Post by Deleted on Feb 4, 2010 19:03:47 GMT
Hi Mick,
The hiss doesn't come in until you crank up. (You'd have to stop the music or you'd deaf)
Mine is prone to mains hum and interference. The hum is extremely low level and maybe a different power supply would get rid of it.
It's so low down in the sound that it's difficult to detect and rather than hear it properly, you're just aware that it's not as silent as other amps.
Nice smooth sound though and easily drives Senn HD650 and AKG 701.
Ian
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Post by Deleted on Feb 4, 2010 19:22:29 GMT
Hi Ian,
done as you said, very slight hardly audible hiss comes in at 2oclock, cant imagine what Headphones would require this setting to be comfortable when listening, ive heard a good few power amplifiers and if you crank up the volume to this level they all have a certain amount of hiss, and there is no perceptible hum at any level on mine, even on full.
Regards Mick.
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Post by gomez on Feb 4, 2010 19:25:48 GMT
Nice one Mick cracking little device it just happens to be my only HP amp & my bugger hisses even with the volume off !! & no source connected. I've tried different locations different cans different rooms still the same I've spoke to henry he says try another psu, unfortunately don't have another. Pinkie reckons it could be the valve But again I don't have another to try  Still sounds good until the quiet bits then it does my head in !! Anyway you should have that stuff I promised you by Friday Mate.  |
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Post by Deleted on Feb 4, 2010 19:30:28 GMT
Hi Ian, done as you said, very slight hardly audible hiss comes in at 2oclock, cant imagine what Headphones would require this setting to be comfortable when listening, ive heard a good few power amplifiers and if you crank up the volume to this level they all have a certain amount of hiss, and there is no perceptible hum at any level on mine, even on full. Regards Mick. Hiss isn't detectable at listening levels. The hum is not affected in any way by the volume. It's just there. (VERY low) It doesn't come up with the volume. It's my bat ears again. They have caused me lots of problems throughout my life. At one time, I couldn't stand watching TV because of the squeal!!!! Not now though. I'm too old. Ian |
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Post by Deleted on Feb 4, 2010 19:36:39 GMT
Hi Paul,
I have a spare JAN PHILIPS ECG 6922, that came with my X-CAN v3 welcome to try it, should be compatible i think ( unless anyone out there knows that its not!). If we don`t here different, will send it to you.
Mick.
PS I have a Russian 6H23 spare as well.
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Post by gomez on Feb 4, 2010 19:40:29 GMT
Hi Paul, i have a spare JAN PHILIPS ECG 6922, that came with my X-CAN v3 welcome to try it, should be compatible i think ( unless anyone out there knows that its not!). If we don`t here different, will send it to you. Mick. That would be great mate it would help, either fix it or rule out the tube, that is as long as it fits I'm sure someone will tell us shortly |
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Post by clausdk on Feb 4, 2010 19:53:23 GMT
Hi Paul, I have a spare JAN PHILIPS ECG 6922, that came with my X-CAN v3 welcome to try it, should be compatible i think ( unless anyone out there knows that its not!). If we don`t here different, will send it to you. Mick. PS I have a Russian 6H23 spare as well. This is why this forum rocks  |
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Post by Deleted on Feb 4, 2010 19:59:10 GMT
Ian,
There is no hum at all on mine, i have turned everything off and on that`s around it, and no hum.
I have been listening to it for an hour now,( been playing to itself all afternoon) all types of music, the Bass is simply stunning, its sooooo musical, its HIGHLY recommended by me, £63 what a bargain.
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Post by gomez on Feb 4, 2010 20:22:24 GMT
Hi Paul, I have a spare JAN PHILIPS ECG 6922, that came with my X-CAN v3 welcome to try it, should be compatible i think ( unless anyone out there knows that its not!). If we don`t here different, will send it to you. Mick. PS I have a Russian 6H23 spare as well. This is why this forum rocks I've got to agree one of the best Forums ever And Mick is one top Fella we've enjoyed a few conversations and exchanges. Them rings look stunning Mick you are a true Craftsman |
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Post by Deleted on Feb 4, 2010 20:51:42 GMT
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Post by gomez on Feb 4, 2010 21:00:30 GMT
I agree Mate sounds great getting rid of the hiss will just be the icing just been listening to Peter Gabriel So sounds great. Which Vangelis would that be Mick ? I may give it a spin next |
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Post by Deleted on Feb 4, 2010 21:15:06 GMT
Portraits Paul, give Weather Report`s "Black Market" Gibralter track, a spin too.
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Post by PinkFloyd on Feb 4, 2010 21:45:16 GMT
Hi Gomez, Nope, no hiss on mine. It could also be the valve, do you have a 6922 / E88CC you could pop in? Mike. Nope, it's as quiet as a mouse Gomez. |
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Post by PinkFloyd on Feb 4, 2010 21:49:38 GMT
Just remember to follow these instructions when rolling in new valves guys: Biasing using a multimeter: The simple adjustment is as below.
Insert the tube and power on,
Let it pre heat for 5 min,
Measure the volts to tube plate (pins 1 & 6)
Turn the pots one by one reach to 16-17V, pin 1 & pin 6 should be same Volts after trimming.
Recheck after one hour and turn the pots again to fix the plate volts (16-17V)
This is not a real precision adjustment, but it will be 90% near to the correct point.
BTW please watch the circuit diagram:  I have been rolling in a few without paying any attention whatsoever to the bias and they all perform well but it's best to follow the above instructions to "optimise" the bias as best as you can with a simple multimeter ;D |
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Post by gomez on Feb 4, 2010 22:04:04 GMT
Hi Gomez, Nope, no hiss on mine. It could also be the valve, do you have a 6922 / E88CC you could pop in? Mike. Nah got no valves at all mate New to this old technology Does you psu make a noise till the amp is on ? Hmmm Well Mick has offered to lend me either a JAN PHILIPS ECG 6922 or a Russian 6H23 if they will fit maybe you can advise ? So I've just got to try & find a 21v psu to try that other than that it will be heading back to Hong Kong I love it but can't put up with the hiss. |
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Post by PinkFloyd on Feb 4, 2010 22:07:09 GMT
Nice one Mick cracking little device it just happens to be my only HP amp & my bugger hisses even with the volume off !! & no source connected. I've tried different locations different cans different rooms still the same I've spoke to henry he says try another psu, unfortunately don't have another. Pinkie reckons it could be the valve But again I don't have another to try Still sounds good until the quiet bits then it does my head in !! Anyway you should have that stuff I promised you by Friday Mate. Paul, PM me your details and I'll send you down a couple of new valves to try.... a 1960's NOS 6H23N and a Mullard E88CC..... I'll test both before I send to ensure they are 100% spot on both in measurement and audibly. I reckon the hiss you describe denotes faulty valve, I may be wrong but am 90% sure that's what it is..... I'd ask Henry to send you another EH valve too..... With all these valve donations you will be able to start a "Bravo valve rolling" thread all of your own ..... PM me, I'll get them over to you ASAP. Mike. |
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Post by Deleted on Feb 4, 2010 22:24:19 GMT
Mike , Have you got any 1960 Russians left for sale, if so i would like a couple for my Pinkie moded X-CAN V3, if possible please. |
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Post by gomez on Feb 4, 2010 22:37:57 GMT
Cheers Mike Pm sent Your Help is very much appreciated. I’ve been into Music & HiFi for years but only recently started getting into headphone this is my first Hp Amp & the modded 681’s the best cans I’ve had. It's been great going through all my albums & hearing them in a new way. Tonight we’ve played The Floyd ,Robin Trower , Wishbone Ash, Waters solo stuff, Gabriel , etc etc it’s been great until you get to a quiet passage (The Pro’s & Cons) then your bubble is burst it’s back to reality with HHHHIIIIISSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS |
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Post by PinkFloyd on Feb 4, 2010 22:53:29 GMT
Nah got no valves at all mate New to this old technology Does you psu make a noise till the amp is on ? Hmmm Well Mick has offered to lend me either a JAN PHILIPS ECG 6922 or a Russian 6H23 if they will fit maybe you can advise ? So I've just got to try & find a 21v psu to try that other than that it will be heading back to Hong Kong I love it but can't put up with the hiss. NO..... it will NOT be heading back to HK.... I'd like to think that Henry will ship a new EH valve over to you to save on shipping costs.... IMO, from what you describe, it's the valve NOT the PSU...... if it turns out to be the PSU I'll eat my hat and send you a 5amp PSU |
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Post by PinkFloyd on Feb 4, 2010 22:57:03 GMT
Mike , Have you got any 1960 Russians left for sale, if so i would like a couple for my Pinkie moded X-CAN V3, if possible please. I'll do you a couple of UBER rare 1969 vintage Mick.... never seen the light of day (in cartons)....... PM me your details and I'll ship them on Monday...... I owe you one, or two Mike. |
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he seems to think it may be caused by a faulty psu, he said to try to use another 24v 1 amp psu to see if it fixes the problem, however I don't think I have got anything like that hanging around.
