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Post by Rabbit on Mar 29, 2013 16:50:57 GMT
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Post by Deleted on Mar 29, 2013 19:16:52 GMT
Hi Ian That's from Oliver, who when only 19 tried to use R.G. as a springboard for fame and fortune, and BS about his technical qualifications. He then arranged group buys in DIY Audio for this. However, his group buys appeared to go alright, although I suspect he was more about trying to make money by selling assembled units for those who didn't wish to build the kits, and building himself a reputation. We used to joke about the designer being Frans's evil twin. Regards Alex
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Post by Rabbit on Mar 29, 2013 19:46:02 GMT
Now you mention the name, Oliver .... I remember him now!!! Whoops .........
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pingu
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Post by pingu on Mar 29, 2013 21:10:38 GMT
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Post by Deleted on Mar 29, 2013 22:34:12 GMT
Martin In all seriousness it's just another well performing opamp based headphone amplifier. There is nothing too special about it's design. Frans de Gruitjer's design was far more comprehensive, and also had user controls such as gain adjustments, bandwidth adjustments and was better able to match different types of, and different impedance headphones due to internal user selectable switches.That guy's main claim to fame was being banned from HeadFi. That's nothing special either, as Mike managed to do the same long before him! Regards Alex
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Post by PinkFloyd on Mar 29, 2013 22:40:12 GMT
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oldson
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Post by oldson on Mar 29, 2013 22:56:16 GMT
That's nothing special either, as Mike managed to do the same long before him! Regards Alex[/quote] SPILL
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Post by Rabbit on Mar 29, 2013 23:20:59 GMT
It's basically a CMoy isn't it? There's something odd going on with the gain though which could mean some distortion creeps through from high output devices!!
He claims though, that this has a 'see through' sound. Amazing eh?
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pingu
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Post by pingu on Mar 29, 2013 23:39:12 GMT
Martin In all seriousness it's just another well performing opamp based headphone amplifier. There is nothing too special about it's design. Frans de Gruitjer's design was far more comprehensive, and also had user controls such as gain adjustments, bandwidth adjustments and was better able to match different types of, and different impedance headphones due to internal user selectable switches.That guy's main claim to fame was being banned from HeadFi. That's nothing special either, as Mike managed to do the same long before him! Regards Alex LoL banned from Head Fi....... my daughter got banned from the local deaf club when she was learning sign language ...... for shouting. (got a bit carried away with her arguement , arts graduate too) Looked at his web site and I thought it was a bit "too good" especially the ordering times. Seems he can make a bit on the money in the bank for a few weeks and a "proper" supplier can send by return, just struck me as a bit of a chancer, and wondered who/where it was being put together. No offence to anyone intended just my impressions. I'll stay with the JLH H/A Thanks all for the info Martin
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Post by Deleted on Mar 29, 2013 23:42:45 GMT
It's basically a CMoy isn't it? There's something odd going on with the gain though which could mean some distortion creeps through from high output devices!! He claims though, that this has a 'see through' sound. Amazing eh? Ian This design is helped by using an I.C. buffer stage at the output , so it should outperform a normal CMOY into medium to low impedance headphones, at the expense of higher quiescent current drain. Regards Alex
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Post by Rabbit on Mar 30, 2013 9:51:59 GMT
Hi Alex, It's this bit I was wondering about: 'Significantly reduced Johnson Noise by placing the first gain stage before the potentiometer'.
I didn't know Mr Johnson was so noisy!!
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Post by Deleted on Mar 30, 2013 10:48:44 GMT
Hi Alex, It's this bit I was wondering about: 'Significantly reduced Johnson Noise by placing the first gain stage before the potentiometer'.
I didn't know Mr Johnson was so noisy!!
Hi Ian That is an old technique to improve S/N ratio. Electronics Australia used that in a preamp years ago, and went into great detail about the improvement in S/N. Silicon Chip also did similar in their Studio Series preamp, from which the SC ( Jaycar) HA came. It comes down to whether you would prefer as small improvement in S/N for an impeccable low noise source, and possibly hear the small audible degradation and sound signature of 2 of the same type opamps in tandem. ( I can ) OR sacrifice a little S/N that may not be noticed , by having the volume control at the input to the I.C./amplifier. It's always best to use no more gain than necessary, so that maximum usable volume is with the volume control almost at minimum attenuation. (almost fully clockwise setting) Regards Alex en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise
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Post by Rabbit on Mar 30, 2013 12:56:26 GMT
Thanks Alex. Interesting about the gain, since I read on some review that the O2 was better at low gain rather than high. (as most amps seem to be) Some people even have them set a 1X gain on low and 2.5 at high. I have my Neco at about 3, I think it is. It is very low in the noise department. (By ear anyway). There's also something about the ground and the use of two batteries rather than one. I'm just curious because he made so many claims about this amp. Maybe that's why he made the claims
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chris1967
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Post by chris1967 on Mar 30, 2013 19:14:22 GMT
I have this amp from the time it became available... mine is from JDSlabs...
There is another thread somewhere about this amp in here but not much interest in the thread at the time...
I feel (now that i have many listening hours with it), that it is very transparent, analytic, but lacks in body... and therefore it may be perceived as thin sounding or bright...
It is powerful and it drives all my headphones with ease, although the more difficult ones it might be a tad on the thin/bright side.
This is going to be worse if it is partnered with less than good equipment... inferior cheap DAC's etc...
The review in headfonia although at the time i thought that it was biased against this product, was in fact very accurate in describing it.
If you have a Neco or any decent portable, there is no need to purchase one.
It may be a good starting point for someone just getting into headfi...
Some of my experienced diyer friends tell me it can be improved by getting rid of the battery power and (with minor modification) installing permanent external power... but this doesn't interest me... it is already in my headamp museum...
Retrospectively i find it a decent buy... i have no interest in debating the person that designed it... he has done a decent job, and that is it... no more no less... it is a good budget amp, it is nowhere near some of the well known amp designs.
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Post by Rabbit on Mar 30, 2013 20:26:37 GMT
Thanks Chris. It's quite puzzling since he makes such big claims about it and the fact that it's even good with a K701/K702; with a very low output impedance and batteries to power it. He even claims it sounds better than much more expensive amps as well.
The reviews are all over the place and as I said earlier, the idea of putting 'gain stage before the potentiometer' which suggests that a high output device could perhaps have distortion all the way through the travel of the pot - regardless of what volume you listen at; although Alex says it's an old tried principle to reduce noise.
I wonder whether people are worried about writing what they hear?
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Post by Deleted on Mar 30, 2013 20:56:07 GMT
Hi Ian Yes, it does seem a bit silly having something like a CD player with an output of 2V RMS being amplified before being reduced at the potentiometer again, especially as lower output levels from the opamp are likely to be in Class A.(load resistance permitting) However , they usually split the desired gain between the 2 opamps, and use a much lower resistance potentiometer in between them.. Years ago they used such techniques to help with lower output level devices such as R.I.A.A. phono preamps and tape decks, and used resistive attenuation to pad back the level of a CD input. Perhaps Marc has a few comments here from the perspective of an E.E. ? Regards Alex
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ronzo56
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Post by ronzo56 on Mar 30, 2013 21:03:42 GMT
Hi Alex, It's this bit I was wondering about: 'Significantly reduced Johnson Noise by placing the first gain stage before the potentiometer'.
I didn't know Mr Johnson was so noisy!!
Johnson Noise. I didn't know they could be noisy! onlineslangdictionary.com/meaning-definition-of/johnson A lot of the fuss over this amp were due to the claims the designeer was making on his website. Many people became followers and others started to slam him and his followers. Then came claims that this amp sounded as good as any multi-thousand dollar amps from high end companies, etc. etc. Then the war started over here. People loved this guy or hated him. If you liked the amp, you had bad hearing. And so forth and so on. I spent some time at a meet with a couple of these amps. They were OK. Not the end of the world good. Just OK. From speaking to people who know about design, not anything breakthrough either, but better than some of the new stuff that is out there. Since he vanished almost a year ago, some folks are speculating that he might be posting under an alias. Sounds like an old cold war story.
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Post by Rabbit on Mar 30, 2013 21:12:01 GMT
I guess it's the equivalent of getting the signal to noise ratio as good as possible and then reducing via the potentiometer so the noise is reduced even further? Just guessing here. However, I'm wondering just how much you can put in before low levels of distortion could creep in on peaks if the gain before the potentiometer is a little too high. I guess it's always possible to put attenuators in.... I had an amp similar in that it seemed too high on the input side, so that everything kind of bordered on distortion at every volume setting. Well, the guy who designed it is an EE so I guess he knows what he's doing!! Most people have reported extremely low noise and black backgrounds. Chris, the Headfonia review is curious. It kind of stands out and isn't too rosy is it? Says it's thin and lacks mids? Funny, because with amps, I find that differences nowadays are pretty small and it's quite difficult to find a 'bad' amp really. Headphones are another thing altogether, but amps are pretty good generally.
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Post by PinkFloyd on Mar 30, 2013 21:33:12 GMT
"Oliver" was the 19 year old guy Alex....... NWavguy is a lot older and from the US....... Oliver is the guy who is distributing the amp in the UK.
Just thought I'd clear that up.
Mike.
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Post by PinkFloyd on Mar 30, 2013 21:35:18 GMT
@ £99 it would be a good idea to TRY it rather than speculate
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Post by Deleted on Mar 30, 2013 21:52:55 GMT
"Oliver" was the 19 year old guy Alex....... NWavguy is a lot older and from the US....... Oliver is the guy who is distributing the amp in the UK. Just thought I'd clear that up. Mike. Hi Mike I had better check what I actually wrote, because that is what I meant. 19 yo "Ollie" boasted about his technical background in RG, when he was of course too young to have had any real formal training. That was before he had anything to do with NWavguy's design, and before we sent him packing. When he put his hand up in DIYAudio to host the G.B. of NWavguy's design, I contacted a U.S. DIYAudio moderator to warn them to keep a watch on the G.B. because of his age, inexperience, and boasting here. NWavguy was of course the guy we used to refer to as Frans's evil twin. IIRC, he was kicked out of HeadFi because of his criticism of the Schiit H.A., which put out a rather high level of D.C. when switched off. Kind Regards Alex P.S. Alzheimers hasn't kicked in yet!
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Post by PinkFloyd on Mar 30, 2013 22:12:32 GMT
"Oliver" was the 19 year old guy Alex....... NWavguy is a lot older and from the US....... Oliver is the guy who is distributing the amp in the UK. Just thought I'd clear that up. Mike. Hi Mike I had better check what I actually wrote, because that is what I meant. 19 yo "Ollie" boasted about his technical background in RG, when he was of course too young to have had any real formal training. That was before he had anything to do with NWavguy's design, and before we sent him packing. When he put his hand up in DIYAudio to host the G.B. of NWavguy's design, I contacted a U.S. DIYAudio moderator to warn them to keep a watch on the G.B. because of his age, inexperience, and boasting here. NWavguy was of course the guy we used to refer to as Frans's evil twin. IIRC, he was kicked out of HeadFi because of his criticism of the Schiit H.A., which put out a rather high level of D.C. when switched off. Kind Regards Alex P.S. Alzheimers hasn't kicked in yet! 100% correct
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Post by Rabbit on Mar 30, 2013 22:28:40 GMT
Alzheimers hasn't kicked in yet! I might have a touch of it 'cos I forgot all about him!!!
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Post by Deleted on Mar 30, 2013 23:02:35 GMT
Solderdude perhaps ? Perhaps Frans has a wife and family in the U.S.A. too ? TBH though, I think that Frans is even smarter than NWavguy.
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pingu
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Post by pingu on Mar 30, 2013 23:10:58 GMT
Having had a look at this amp on u tube it certainly looks a tiny bit of kit and is well presented. HFW usually do good reviews on the stuff, I would be inclined to trust their view more than other mags, and 5 globes is good. However the long lag between order and shipping is a worry for a mass produced item (at least from my point of view), it could be your young lad is financing his orders from customers payments?? (just under the credit card grt limit too ) But as Mike says £99.00 it is certainly a good price Martin
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