Torpedo Posted February 20, 2009 Report Share Posted February 20, 2009 Recently I purchased a B22 from Spritzer. The unit was built by Nate, so it's a nice Nugget Audio 3 boards + 1 Sigma 22, single ended, 8x gain unit, made to work on 230VAC. Apart from exquisite care to avoid hum and lower the noise floor, it features a dual input to select from two sources from a rear switch. Spritzer had changed this feature to a loop, so the switch was disabled and while one of the inputs is used, the other one works as an output. I point this because that switch resulted a handy addition. The amp works very well and sounds great with all of my cans, but as time living with it passed, I started to feel annoyed for the fact that being my source 3V output and the gain 8x, it was very difficult to get a comfortable listening SPL when using phones with more than 97dB/mW sensitivity, so almost everything in my stash but the Fostex T30. The volume pot is a nice Noble which Spritzer used to replace the original Alps that Nate mounted, which had become noisy according to Spritzer. This Noble is a 10KOhm pot, quite well matched in all of its range but very low level when high attenuation is used. So my problem was that to get a comfortable SPL I had to get it working at a point a bit above the minimum, passing the point where the right channel sounded louder than the left one. But that was a very narrow spot, a bit above that, or when listening to recent recordings (the ones being very compressed and produced at almost 0dB all the time) sound became to be too loud for me. To be more descriptive, I'd say that my usable range with most cans was between 6:30 and 7:15, and with the T30 from 6:30 to 9:00 depending on the recordings. Otherwise I was listening too loud and after a couple of discs, tinnitus appeared I'm no DIYer and have little electronics knowledge, so I contacted n_maher and Spritzer to advise me about which of these choices would be preferable: - Lowering the whole unit's gain to 4x or 2x - Changing the volume control for a stepped attenuator which customized, provided more attenuation than usual in the 5-10 first steps of its range. - Adding extra attenuation at the input. The first choice, lowering the gain is a lot of work. You need to change 4 caps and 2 resistors on both channel boards, and then adjust a trim resistor to get 0 DC offset on each board. It's doable, but still could be not enough and would leave the unit less practical for speakers use or if using very insensitive cans like K1000. Not one of my plans but who knows. The second choice was quite interesting, but a custom attenuator would be rather expensive. So it seemed the third option was the easiest and more affordable. While thinking about it, Spritzer suggested me to contact Ti at AMB Labs so maybe he could advise other alternatives or how implementing them. Ti replied really fast and very helpfully that an interesting work around would be implementing a switchable attenuator, so in one position I would leave the signal untouched and the gain set at 8x, while at the other position, the signal would undergo attenuation provided by one in series resistor and other paralleled resistor. Their values should be calculated depending on the volume control's impedance and desired level of attenuation. The scheme is this: The explanation was posted by Ti at Headwize some time ago. I told all this to my friend Juan Ramon (Hitoridekimasu here) then he came to my place with some parts, his own diagram on how to implement it, and his multimeter which is way better than mine, to match the resistors and check everything was right. By applying this formula: . Rb At= -------------------------- *(see foot) . ( Rb Quote Link to comment Share on other sites More sharing options...
Beefy Posted February 20, 2009 Report Share Posted February 20, 2009 I was completely confused for a while there, because the switch wasn't drawn as I expected. I should really learn to read schematics better But all clear now...... it is basically a voltage divider before the pot, and the switch just shorts it out or engages it. Quote Link to comment Share on other sites More sharing options...
aardvark baguette Posted February 20, 2009 Report Share Posted February 20, 2009 wow, this amp has been all over the world Quote Link to comment Share on other sites More sharing options...
Torpedo Posted February 20, 2009 Author Report Share Posted February 20, 2009 wow, this amp has been all over the world Yep, I don't know if it's because it's good enough to make previous owners to wish getting a balanced one with "moar blackgates", or because it sucks and everybody gets rid of the poor thing Quote Link to comment Share on other sites More sharing options...
grawk Posted February 20, 2009 Report Share Posted February 20, 2009 I frequently sell the better of 2 things, if the lesser of the two fills my needs. I don't feel a compulsion to own the best. Maybe that's what's going on here too... Quote Link to comment Share on other sites More sharing options...
aardvark baguette Posted February 20, 2009 Report Share Posted February 20, 2009 I sold it based out of stupidity and the need for cash. Quote Link to comment Share on other sites More sharing options...
Torpedo Posted February 20, 2009 Author Report Share Posted February 20, 2009 I sold it based out of stupidity and the need for cash. You're going to make me feel a lucky guilty bitch Of course it's clear I was joking, this puppy doesn't suck at all. Probably the best headphone amp has visited this place so far. If overkill has a paradigm, a B22 definitely is. Quote Link to comment Share on other sites More sharing options...
aardvark baguette Posted February 20, 2009 Report Share Posted February 20, 2009 If overkill has a paradigm, a B22 definitely is. Thats it in a nutshell, for me. I was using it at the office. Some days I can listen to music for hours, but more often than not I get interrupted by this or that, and only get in maybe 2-3 hours of music. Quote Link to comment Share on other sites More sharing options...
deepak Posted February 20, 2009 Report Share Posted February 20, 2009 You're going to make me feel a lucky guilty bitch Of course it's clear I was joking, this puppy doesn't suck at all. Probably the best headphone amp has visited this place so far. If overkill has a paradigm, a B22 definitely is. I still haven't heard one, but I've started to want a Beta22 again now that I have some hard to drive headphones (orthos) Quote Link to comment Share on other sites More sharing options...
Torpedo Posted February 20, 2009 Author Report Share Posted February 20, 2009 Start hunting Deepak. I only have the T30s orthos. They sound quite good from the Gilmore Ref, but the B22 really drives them, stopped thinking about damping them. If I could only get the right pads for these things... Quote Link to comment Share on other sites More sharing options...
spritzer Posted February 20, 2009 Report Share Posted February 20, 2009 The T-50v1 was awesome with that amp... Quote Link to comment Share on other sites More sharing options...
deepak Posted February 21, 2009 Report Share Posted February 21, 2009 If I can get a modded YH-100 to sound a level above the HP-1 I think a 2 ch Beta22 is in my future. Quote Link to comment Share on other sites More sharing options...
Torpedo Posted February 21, 2009 Author Report Share Posted February 21, 2009 Yep, just for your information, when using the T30 I'm better served using the B22 in the no attenuated mode and I don't listen loud. Those things eat power like Apogees. Quote Link to comment Share on other sites More sharing options...
deepak Posted February 21, 2009 Report Share Posted February 21, 2009 Yep, just for your information, when using the T30 I'm better served using the B22 in the no attenuated mode and I don't listen loud. Those things eat power like Apogees. Yup, even with my unmodded HP-1 (more efficient than modded ) there were only maybe 2-3 amps at the NY meet that could really drive them. Quote Link to comment Share on other sites More sharing options...
Torpedo Posted February 21, 2009 Author Report Share Posted February 21, 2009 Which were the others? just in case Quote Link to comment Share on other sites More sharing options...
deepak Posted February 21, 2009 Report Share Posted February 21, 2009 Which were the others? just in case WA5, for sure. I can't remember the others Quote Link to comment Share on other sites More sharing options...
Smeggy Posted February 22, 2009 Report Share Posted February 22, 2009 (edited) They are wee terrors that eat most amps for breakfast! I still find it amazing that the mini3 can do such an awesome job of driving orthos. All except for the most difficult orthos sound really good with it. Superb bass control and power with the T50RP and SFI 120s though the 120s have the volume at 2/3 as opposed to 1/2 for the T50. I'm not even going to try the Wharfedales on it though, they need shitloads of power which is why they came with speaker adapters. I imagine the Beta22 will do them all justice Edited February 22, 2009 by Smeggy Quote Link to comment Share on other sites More sharing options...
Kabeer Posted February 22, 2009 Report Share Posted February 22, 2009 They are wee terrors that eat most amps for breakfast! I still find it amazing that the mini3 can do such an awesome job of driving orthos. All except for the most difficult orthos sound really good with it. Superb bass control and power with the T50RP and SFI 120s though the 120s have the volume at 2/3 as opposed to 1/2 for the T50. I'm not even going to try the Wharfedales on it though, they need shitloads of power which is why they came with speaker adapters. I imagine the Beta22 will do them all justice yup its great with orthos! And its a decent price. Dbel is giving me a speaker adapter to try my wharfedales with my speaker amp. Quote Link to comment Share on other sites More sharing options...
deepak Posted February 22, 2009 Report Share Posted February 22, 2009 Are you guys sure it isn't just the gain being set high on your mini3s? I have a hard time believing battery power could drive a tough load like the ortho presents. I'm convinced they need really powerful amps after hearing most fail horribly. I have a very high gain tube amp (gain 22 I think?) that gives the illusion of driving the Yamy properly, but it's a whole different beast on powerful amps. Quote Link to comment Share on other sites More sharing options...
Smeggy Posted February 22, 2009 Report Share Posted February 22, 2009 (edited) My gain is set high, however it does a damn good job driving them, as good as my speaker amps. The mini seems to put out plenty of clean power that does a very nice job driving them with no trouble at all. Many complain of a lack of deep powerul bass with orthos, this always confused me because I was getting earth grumblingly powerful bass. Once they tried more powerful (speaker) amps the sound blossomed. You need an amp with reasonably good current delivery and the mini seems to be quite happy doing that. At the expense of batter life that is. I only average about 6-7 hours on a charge I was very surprised and pleased at the results from it. The T50RP isn't too difficult a load but the SFI 120 is a pig and the Yammy orthos are middling. I'm pretty sure the B22 will be in a whole different league. Just in case you were wondering, it's not a case of them just going loud, it's loud, clean, no clipping/distortion or strain of any kind right down to <20 hz. I'm not sure how the mini3 does it but I suspect it's the speed it can drain a battery into my phones Edited February 22, 2009 by Smeggy Quote Link to comment Share on other sites More sharing options...
deepak Posted February 22, 2009 Report Share Posted February 22, 2009 Good god the SFI 120 must be a beast if the Yamy is middling in comparison My stock HP-1 made most of the amps I tried cry, and in modded form... Quote Link to comment Share on other sites More sharing options...
Smeggy Posted February 22, 2009 Report Share Posted February 22, 2009 Yep, the Yammys are right in the middle of the orthos drive-wise. My 120s are made worse because I have them mounted in such a way that you need even more power to drive them. Ericj has my Wharfedales and he says they are the least efficient orthos he's come across. I suspect most headphone amps are much happier putting out volts into efficient loads, not what you'd want for an ortho. Quote Link to comment Share on other sites More sharing options...
Kabeer Posted February 22, 2009 Report Share Posted February 22, 2009 I think the mini3 high performance model (higher current output), is set somewhere around the 4.5-5.5x gain mark. So nothing amazingly high. I dont have any monster amps to test with so Im just going by my experience of the Starving Student and the other portable amps i'v had before. I guess smeggy has some nice old receivers to power stuff so he knows what he is talking about . When you get your b22 smegg it will be interesting to hear how well it does with orthos. edit: Btw, the hardest thing to drive at the moment in my stable is the HP-50S, and thats because iv damped it soooo hard its crazy. Quote Link to comment Share on other sites More sharing options...
deepak Posted February 22, 2009 Report Share Posted February 22, 2009 Hehe the little HP-50 is an awesome headphone Quote Link to comment Share on other sites More sharing options...
Smeggy Posted February 23, 2009 Report Share Posted February 23, 2009 I've still never heard one though Colin said he'd send his over for a listen so that should be fun. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.