Torpedo

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.

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...

Have a great one mate!!!!

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.

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

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

Yep, I can receive the boards and parts for the Spanish team and deliver them to Hitoridekimasu and Picaudio, or maybe it's more sensible Picaudio receives them (since he's building my boards) and just sends to Hitori his share. No worries, we'll try to make things easier for you Also if you are sourcing parts from Europe which we are using too, we could order and get them, then sending the US part to you, perhaps that saves you shipping costs or custom duties. Even if we weren't using any of them, if some of you needs parts from this side of the pond and we can be of any help, just let us know.

Very good option. I'll wait for Picaudio's comments since he'll be building my amp. Maybe the spanish group sums to it.

Sure, I took some pics of the works. When I upload them I'd open a thread at the DIY forum. It may take a few days though.

Thanks for the comment j4cbo. If the controller board compares that favorably price wise and includes the resistors for the volume control, it makes sense. However dealing with smd soldering can be a problem for some. Maybe leaving that optional if possible might be interesting.

Hitoridekimasu came to my place and we implemented on the B22 a switched attenuator which allows to choose to leave its 8x gain untouched or drop it down to 1.5x (more or less). Fantastic results now I can listen to the PS-1 and other sensitive cans at comfortable levels having the volume pot away from its unbalanced lowest range (right channel louder than left one) and where it allows very fine loudness adjustments. Surprisingly, perhaps for the pot working in a range where it's more lineal or has better channel balance, it sounds a tad bit more open. Thanks to Nate and Birgir who suggested the solution, and to Ti who provided the circuit diagram. Hitori calculated the resistor values to have the gain at the desired level. This B22 sounds damn good

How much raises cost having the controller board for monitoring temperature, selecting source and controlling the volume stepped attenuator compared to mounting a good volume pot and analogue selector switch? Not very worried about the raw cost, but for the noise and additional circuitry and complication it means.

^ Funny

Definitely, if it weren't for my friendship with PICaudio (Rodrigo) I could only participate in the non-Diyer version which just required soldering a few connectors and screwing boards in place. But I think this was the original idea, that people not being skilled DIYers themselves could get the tough work done by someone else, while the pure DIYers could get every single bit and piece apart to build the whole thing by themselves.

Very Happy Bday

It's not very much what I can comment or help since my boards would be built by PICaudio and somehow my participation is linked to his willing to stick into the project. I believe the built amp would be worth those 1300-1500 bucks, probably more considering the prices commercial products carry. Still a lot of money and we'd have to clear up a few things yet. Maybe we'd need to know how many of us are still in it, and if most people want to build their boards and PS or having them built by someone else but mounting them into a chassis, or even if some prefer having the whole thing built by other person. Also if we'd have the same enclosure for all to make cost lower (which maybe wouldn't be that interesting for the ones of us living outside the US), hence if everyone wants a single chassis amp or prefer a two chassis one. It also would be good knowing if everyone will use S22 power supplies or someone is willing to build the original PS Kevin designed for the Dynafet. Once we know all this and have a recount of all variables we'd see if it's still feasible.

Yes and no. It's very sad and quite tough when you face the moment of realizing nothing else can be done, and telling so to the relatives or the own patient. But it also has a good part which is reminding you how damn lucky you are. Kinda makes you appreciate better what you have and enjoying it while you have it. Who knows, maybe this little girl can go through a few weeks more and in the meanwhile a kidney for her arises.

Yep, the poor wee girl has other conditions which don't help to let her grow up as much as she should. She'd need a kidney transplant to survive. Life sucks sometimes

Couldn't find the exact match, the most likely candidates are the 4101-NT or the 4101-SPL-NT Look very nice, with rosewood fretboard, sapelli sides and back... one seems a dreadnought with spruce top and the other a classic shape all in sapelli (Entandrophragma cylindricum, whatever it is in English), so I was wrong in my reference coding guess. I hope she likes the guitar

Made a tracheotomy on a 9 month old, 12 pounds weight baby in the yesterday on-call shift Fortunately she had a secured airway, otherwise it had been a real nightmare.

I'm late. Happy belated Birthday, or should it be belated Happy Birthday? I hope you had a great one mate.

I think it should be a Gold Formosa. Those guitars are manufactured in Taiwan. Have been searching their website but couldn't find the 4104 model, though they have others being quite close like 4101 and 4102. Not sure about their model coding, but seems 41xx are dreadnoughts. Maybe you can contact them and asking about it.

The pre-emphasis was something they designed to "prevent" a damage to the high frequencies for the use of brick wall filters in the early RBCD era. It's just EQ and can be reverted by applying the same curve as it's done for the RIAA curve in vinyl. I read somewhere that the EQ curve comes from applying a time constant of 15/50 μS depending on frequency. In fact I've found the source of that and I post here what someone who seems knowledgeable wrote about it:

Hey, that castle is in Manzanares el Real, a village at about 40 miles from Madrid. I used to spend the summer holidays there with my grand parents when I was a child. World is damn small hahahaha. Funnily enough in that town and the mountains around some Hollywood movies were produced. I think Charlton Heston's "El Cid" was filmed over there.

Glad to know you received attention in time. Get better