[MrMajestic2]

Just got my new HD650s and I just had to balance them right away. Listening now on my B22 and it sounds fantastic

Can you spell synergy, amazing.

 

[fault151]

Id love to hear that! I have some hd600's and i bet they would sound very nice balanced. I cant wait to make mine!!!

 

[MrMajestic2]

Quote:

Originally Posted by fault151 /img/forum/go_quote.gif Id love to hear that! I have some hd600's and i bet they would sound very nice balanced. I cant wait to make mine!!!

Come over to Stockholm and have a listen

 

[el_matt0]

@ fault, just out of curiosity what amps / etc DIY stuff have you built in past, just for a point of reference? I'd just like to know so I can give you my own advice, because about a year or so ago I was in exactly the same position as you, fairly new to DIY, and that was the stage that I had contemplated building my balanced b22. However I had at that stage already built at least 4 or 5 cmoys, 1 millet max, and a soha with jisbos, along with an alien dac. Even with those earlier builds, I still ran into some troubleshooting issues with my beta22 that took an extremely long time to work out due to my inexperience, and that was even WITH the help of all these fantastic forum members. With the 4 board b22, the inability to use e22's really adds to the wiring mess/complication, and especially if your fairly inexperienced, this could lead to some major headaches and confusion. As others have stated earlier, theres really a lot more to building one of these than simply following step by step instructions and stuffing components into a PCB (which a trained monkey could do). I'm just really interested to know what DIY you've got under your belt before taking up such a major project, it would be nice to know!

 

[bperboy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif For β22 serving as a headphone amp, I do not recommend putting the transformer(s) there. Too close to the amp boards and you'd hear hum/buzz.

A little off topic, but is having a transformer in the same case as amp boards not such a huge deal with hum in the case of a speaker amp as opposed to a headphone amp? And if so, why, and if not, why not?

 

[amb]

Quote:

Originally Posted by bperboy /img/forum/go_quote.gif A little off topic, but is having a transformer in the same case as amp boards not such a huge deal with hum in the case of a speaker amp as opposed to a headphone amp? And if so, why, and if not, why not?

Headphones are much, much more efficient than speakers. Grados, for example, are said to be 98dB SPL at 1mW, which corresponds to about 178mV into 32 ohms. Contrast that with a fairly efficient speaker at 90dB SPL at 1W and 1 meter distance, which is 2.83V into 8 ohms. To get to the equivalent of 98dB SPL, you'd have to drive that speaker with a bit over 7V of voltage. 7V vs. 178mV is almost 40x difference, so given these two examples, a hum problem in a speaker amp will have to be 40x stronger in voltage amplitude than that in a headphone amp to be perceived as equal in loudness.

Headphone transducers sit right next to your ears. Even a small amount of hum will be easily audible. The same small magnitude of hum will be difficult to hear even if you put your head up next to the speaker, and will certainly be inaudible at normal listening distances (which is usually much farther than 1 meter). Add to this the fact that headphone earcups tend to isolate ambient noise to some degree (even open air types), but there is no such effect with speaker listening. So a small amount of hum through speakers will likely be masked while it would be quite distinct in a headphone.

 

[bperboy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif Headphones are much, much more efficient than speakers. Grados, for example, are said to be 98dB SPL at 1mW, which corresponds to about 178mV into 32 ohms. Contrast that with a fairly efficient speaker at 90dB SPL at 1W and 1 meter distance, which is 2.83V into 8 ohms. To get to the equivalent of 98dB SPL, you'd have to drive that speaker with a bit over 7V of voltage. 7V vs. 178mV is almost 40x difference, so given these two examples, a hum problem in a speaker amp will have to be 40x stronger in voltage amplitude than that in a headphone amp to be perceived as equal in loudness. Headphone transducers sit right next to your ears. Even a small amount of hum will be easily audible. The same small magnitude of hum will be difficult to hear even if you put your head up next to the speaker, and will certainly be inaudible at normal listening distances (which is usually much farther than 1 meter). Add to this the fact that headphone earcups tend to isolate ambient noise to some degree (even open air types), but there is no such effect with speaker listening. So a small amount of hum through speakers will likely be masked while it would be quite distinct in a headphone.

Thanks, that helps a bunch!

 

[fault151]

Quote:

Originally Posted by MrMajestic2 /img/forum/go_quote.gif Come over to Stockholm and have a listen

I would if i could

 

[fault151]

Well iv built a grado amp (very similar to a cmoy), i bought a millet max and changed a load of parts and designed a custom panel at FPE, i upgraded my x-can v3 with all capacitors and resistors and with the help of a friend i built a John Broskie, Aikido valve amp. the valve amp was a fairly difficult build as it involved a lot of calculating what resistors + capacitors i needed and making sure the valves and heaters ran at the correct voltages.It uses 4 valves and a rectifier valve. By no means am i an expert, but I'm learning all the time and I'm bloody determined to make a b22.

Quote:

Originally Posted by el_matt0 /img/forum/go_quote.gif @ fault, just out of curiosity what amps / etc DIY stuff have you built in past, just for a point of reference? I'd just like to know so I can give you my own advice, because about a year or so ago I was in exactly the same position as you, fairly new to DIY, and that was the stage that I had contemplated building my balanced b22. However I had at that stage already built at least 4 or 5 cmoys, 1 millet max, and a soha with jisbos, along with an alien dac. Even with those earlier builds, I still ran into some troubleshooting issues with my beta22 that took an extremely long time to work out due to my inexperience, and that was even WITH the help of all these fantastic forum members. With the 4 board b22, the inability to use e22's really adds to the wiring mess/complication, and especially if your fairly inexperienced, this could lead to some major headaches and confusion. As others have stated earlier, theres really a lot more to building one of these than simply following step by step instructions and stuffing components into a PCB (which a trained monkey could do). I'm just really interested to know what DIY you've got under your belt before taking up such a major project, it would be nice to know!

 

[el_matt0]

@ fault, dont get me wrong, i mean either way its DEFINITELY a fantastic learning experience, just if you are leaning towards the side of inexperience, keep your fingers crossed you dont run into any major troubleshooting issues!

best of luck, im sure ull be fine

 

[fault151]

Quote:

Originally Posted by el_matt0 /img/forum/go_quote.gif @ fault, dont get me wrong, i mean either way its DEFINITELY a fantastic learning experience, just if you are leaning towards the side of inexperience, keep your fingers crossed you dont run into any major troubleshooting issues! best of luck, im sure ull be fine

Cheers, I think the wiring will definitely be the hardest bit. I could almost do with a wiring diagram to follow.

 

[drc73rp]

From our experience it is better to have separate casing for amp section and power supply. Its always nice not to have to worry about hum or any noise due to proximity to the torroidal transformer, and the umbilical with neutrik power connectors look cool too.

With extra space in the PSU casing, i have an option to upgrade to dual Sigma 22 for whatever reason( O yeah.

)

Just make sure to provide enough space at the front for the switches and vol control esp when using stepped attenuators or Joshua tree types. Same case at the back for the rca, speaker and power connectors. I modelled the layout in CAD with the actual board footprint and i still missed out on the extra space for the stepped atten. We almost had to settle for an Alps to keep the knob at the middle center of the fascia, but i couldnt take not having the stepped atten so i settled for slightly offset position.

Im definitely hearing the effect of burn in with the amp at almost 200 hours. The AKG 601's are definitely singing now. Mahler symphonies have become wider and the sound has more weight. There is also better extension in the highs. Whether this is indeed burn in or some other factor, the amp is definitely living up to its reputation now. Now stop reading and build your own.

 

[fault151]

My kit arrived today, can't wait to put the boards together. Hope i can do it!!!!!

 

[fc911c]

Just take your time and don't rush it, I know it's hard not too. Make sure all the right parts are in the right places double check everything, you will be happy you did later on. Also check the polairities and read the instructions a couple of times before you even start.

good luck with the build


Quote:

Originally Posted by fault151 /img/forum/go_quote.gif My kit arrived today, can't wait to put the boards together. Hope i can do it!!!!!

 

[fault151]

Quote:

Originally Posted by fc911c /img/forum/go_quote.gif Just take your time and don't rush it, I know it's hard not too. Make sure all the right parts are in the right places double check everything, you will be happy you did later on. Also check the polairities and read the instructions a couple of times before you even start. good luck with the build

Cheers, i will do. I'm a bit nervous. I think im going to have a trial run with all the parts first, place them on the board, check them, then solder them after.