leo
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Post by leo on Feb 23, 2008 11:59:54 GMT
So any chance this can be passed around the popular members so we can evaluate its performance?
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FritzS
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Post by FritzS on Feb 23, 2008 12:24:07 GMT
I follow this please - give us a chance to test this amp - and we are your promotores, advertising medium, :-)
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insomniac
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Post by insomniac on Feb 23, 2008 16:16:15 GMT
Any idea what the yellow plugs and bare PCB pads 'Out' are for? And what purpose the 4 internal LED's serve? Bare pads / yellow plugs are where line out will be. Internal LEDS, as Mr. Doudou explains, "reference voltage. LED has lower noise than a zener diode" there is also provision on the PCB for a 3.5mm head out..... I don't know if he will be incorporating one. Ahh sorry Mike You mentioned the bare pads earlier in the thread but I had overlooked it somehow
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insomniac
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Post by insomniac on Feb 23, 2008 16:23:33 GMT
Insomniac The drawing below may help explain. LEDs are often used as a quiet and stable voltage reference. As shown , the LED causes a current of 12mA to flow via the collector of the transistor. I often use Blue LEDs for the same purpose. In that case their reference voltage is closer to 3V. LEDs are typically >80 times less noisy than a Zener diode reference. A LED also has a similar temperature coefficient to the transistor, so the result is a pretty stable current flow. I assume that is their purpose in this headphone amplifier. SandyK (The voltage readings shown are for explanation only. Not all Red LEDs have a forward voltage drop of 1.8V) Very interesting SandyK, I have never really thought about LED's being used in that role. I imagined they were there as some sort of diagnosis indicators or something.
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FritzS
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Post by FritzS on Feb 27, 2008 5:22:20 GMT
Mike, whats about Mr. Doudou Headphone Amp now? ;D
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Post by PinkFloyd on Mar 1, 2008 0:00:22 GMT
Mike, whats about Mr. Doudou Headphone Amp now? ;D Fritz, I have been deliberately avoiding this thread as I like to get my facts straight before laying down a final comment. The "Singer" has flaws, let's get them out of the way first..... With 32 ohm 'phones there is a discernable buzz at low to medium Volco levels. The Singer is NOT designed to be used with low impedance 'phones / period. Can it be adapted for use with 32 ohm 'phones? NO! Is that a clear enough message that this amp is a Sennmeister driver? Do NOT buy this amp if your headphone stash consists of 32 ohm headphones only. DEFINITELY buy the Singer if you want to get the best out of your armoury of medium / high impedance 'phones. I have back to backed the Singer with the Graham Slee Solo and the singer absolutely trounces the Solo with high Z 'phones connected... bags more impact, ball crunching dynamics, depth, space, attack.... the "Singer" is leaps and bounds ahead of the Solo in these departments. Plug in a pair of 32ohm 'phones and the Solo soon takes the honours.... The slight buzz at low volume levels with the Singer (with 32 ohm 'phones only) would possibly be annoying to 32ohm users. If you're a seasoned Senn head though the Singer is about as good as it gets and, for the money, constitutes quite a bargain.
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Deleted
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Post by Deleted on Mar 1, 2008 0:08:03 GMT
Then it wouldn't be so crash hot with the Audio Technica ATH W1000 (40 ohms) either would it ?
SandyK
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insomniac
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Post by insomniac on Mar 1, 2008 0:14:52 GMT
Mike, whats about Mr. Doudou Headphone Amp now? ;D I have back to backed the Singer with the Graham Slee Solo and the singer absdolutely TROUNCES the Solo with high Z 'phones connected... bags more impact, ball crunching dynamics, depth, space, attack.... the "Singer" is leaps and bounds ahead of the Solo.......... More to follow....... My Solo might be packing its bags and heading to the for sale section ;D
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Post by PinkFloyd on Mar 1, 2008 0:46:53 GMT
Then it wouldn't be so crash hot with the Audio Technica ATH W1000 (40 ohms) either would it ? SandyK Awesome once the music became louder than the buzzing... actually. pretty shit hot with 40R
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Nigel
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Post by Nigel on Mar 1, 2008 0:50:05 GMT
Grado is a fantastic sound but I have reservations about long term listen-ability.
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Deleted
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Post by Deleted on Mar 1, 2008 1:00:16 GMT
Mike Perhaps there is a power supply, or earthing issue, that needs to be sorted out, before you can give it an unqualified thumbs up ?
Alex
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leo
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Post by leo on Mar 1, 2008 2:20:25 GMT
It wants a good probing, noise can usually be sorted out with a bit of patience
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rickcr42
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Post by rickcr42 on Mar 1, 2008 2:21:13 GMT
Mike Perhaps there is a power supply, or earthing issue, that needs to be sorted out, before you can give it an unqualified thumbs up ? Alex more likely jusy another case of folks expecting an amp that is a "be all things to all headphones" when the reality is that it is far better to use the amp where it shines and look elsewhere for a low-Z driver.Truth is most designers use Sennheisers during the design stage,optimize the sound for then maybetry other brands/types just to see if they will actually play and if they DO then the ad copy says something like "works with all headphones from 32 ohms to 300 ohms" Notice I wrote WORKS WITH not sounds good which are entirely different things so while the above is in fact true in the strict sense of the word the fact is the statement is close to an untruth when you consider what the end result of the "works with" is. Why are there more amps designed for "Eur" cans and not the Grados ? Simple economics.The Grados are hand made in a small shop so will have less worldwide distribution (the archaic trade practice of Grrado labs is no aid either ).The "Euro" cans come from large scale assembly lines and are shipped to every corner of the planet plus the liberal pricing policy where yes there is a MSRP the actuality is the end retailer can set their own price so more likely to be found at a good price (check the pro gear sites if you want to see crazy cheap pricing All ads up to a market where a good 99% of the amps are made to drive a certain transducer type/tone with as far as I know only ONE amp made specifically for the Grado/Lo-Z cans and few others that are in fact dual use amps. This is not a bad thing because by trying to "tweak" an amp for one (and none of that shit about nuetral and how if the amp is nuetral it should not matter because that is a sham unless the amp/headphones are considered ONE UNIT thus balance out) type you end with with an amp/headphone combination that sounds right whereas if you really truly shoot for the middle you end up with an amp that may sound like crap with both but in the end be nothing special. Use the right tool for the job folks ! If you need to screw two pieces of wood together you CAN bang the fker in with a hammer but eventually it will pull apart because you stripped the hole so use the damn screwdriver for screws and a hammer for nails (or bug hunting ) and a Low-Z driver with NO GAIN (or at most if using a portable as source very little) is the only proper driver for the 32-40 hz cans or you are looking for trouble plus any amp voiced to make the senns sing HAS TO have a sonic profle that goes to upper octave detailing which is the exact opposite of what you want in a Grado. no speaker amp is suited to all speakers even though it will DRIVE them,same with headphone amps rick out
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Deleted
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Post by Deleted on Mar 1, 2008 2:59:03 GMT
Rick There still shouldn't be any marked "buzzing" with ANY normal headphone load. I agree that it is very difficult to make make them sound good with ALL different impedance headphones, though. It could also be that the unit may have been knocked around during transportation, and that it was fine when despatched. Perhaps Mike or Leo could hook a CRO up to it's output to see if they can see any sign of the "buzzing" problem. Alex
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Post by PinkFloyd on Mar 1, 2008 12:29:04 GMT
The buzzing is known to Mr. Doudou and it is inherent in this particular amp, I think a quick fix may be to increase the output impedance of the amp to say 100R?
Let me make this clear though, the "buzzing" is barely audible and only annoying if you listen to your music without the volume turned up! as soon as you crank the volco up all you hear is the music. The buzz only happens with 32R 'phones, with higher impedance Senns it is deadly quiet.
I tend to agree with Rick, there is no one amp that can drive everything to perfection.... no such thing as a jack of all trades amp.... This amp is most certainly tuned for the Sennheiser big guns and does an absolutely superb job driving them.
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Post by headtestament on Mar 1, 2008 15:59:09 GMT
Thanks all friends,Thanks for your "welcome". We have been concerned about this measure, but we do not express any opinion because the measure itself should be "open" and "just". At the same time we are also collecting the views of other evaluation as a reference to information.
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leo
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Post by leo on Mar 1, 2008 16:37:24 GMT
Hi Headtestament,
What type of regulation circuitry is used in the circuit? So the buzzing is noticeable even if the pot is set to min? not nit picking but rather trying to get an idea what the source to the buzz may be, there may even be an easy fix. Of course theres ways to mask it but better to see if things can be cured properly if possible IMO
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Post by PinkFloyd on Mar 1, 2008 17:12:42 GMT
Hi Headtestament, What type of regulation circuitry is used in the circuit? So the buzzing is noticeable even if the pot is set to min? not nit picking but rather trying to get an idea what the source to the buzz may be, there may even be an easy fix. Of course theres ways to mask it but better to see if things can be cured properly if possible IMO Hold on!!! It's totally disappeared now All I can think is I was listening with the lid off the other night, now the lid is on NO buzz at all with 32 ohm 'phones. The SR-225 are actually quite beefy sounding powered by the Singer.... let me go and check all this out thoroughly before commenting ;D
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Post by PinkFloyd on Mar 1, 2008 17:27:16 GMT
My apologies for being an arsehole and listening to an amp with it's lid off Now the lid is on there is NO BUZZ with the Grado phones.... I'll have a darned good listen and report back later on. Grado + Singer - Take Two!
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Post by PinkFloyd on Mar 1, 2008 17:28:23 GMT
That reminds me...... I better get the bolts back into the front panel before they go missing ;D
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Post by headtestament on Mar 1, 2008 17:42:47 GMT
Hi leo, The buzzing is only in L-ch,and it 's 50Hz,so possible that noise is the transformer too close to the L-ch, I think of ways to solve the problem. As Mike say it's noticeable in low-impedance headphone,This machine is designed for the more than 100 r headphones , If you use low resistance headphones , we do not recommend that you buy it.
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leo
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Post by leo on Mar 1, 2008 17:54:17 GMT
So it was the discrete circuitry being exposed to the RF because the top wasn't on
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leo
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Post by leo on Mar 1, 2008 18:04:20 GMT
Hi leo, The buzzing is only in L-ch,and it 's 50Hz,so possible that noise is the transformer too close to the L-ch, I think of ways to solve the problem. As Mike say it's noticeable in low-impedance headphone,This machine is designed for the more than 100 r headphones , If you use low resistance headphones , we do not recommend that you buy it. Could maybe fit copper shields over the discrete modules similar to what Marantz uses on their HDAMs, should help shield noise radiated from that traffo
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Post by PinkFloyd on Mar 1, 2008 18:14:34 GMT
A bit of retro anyone? Trying these with the singer too and my god it's driving them superbly! I had these down for the bin not too long ago and they really are lovely sounding 'phones when amped correctly..... more later.
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Post by minivan on Mar 1, 2008 19:34:10 GMT
may be the lip can act as a grounding for the amp? i discovered by chance if i put my solo on top of a metal case, in this case, my other amp or dac, the hum and vibration from the solo reduced dramatically, still can hear hum with low impedance headphone w5000 if i touch the amp with volume turn to the max ,but will high impedance i can hear no more hum.
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