Hi,
A relay solution is the best way to do that, I think so!
You can find a exemple here:
http://www.apoxcontrols.com/apox.htm
Alex
A relay solution is the best way to do that, I think so!
You can find a exemple here:
http://www.apoxcontrols.com/apox.htm
Alex
gchrist said:
That depends on how many items you'll be wanting to switch.
If you only have one item, you wouldn't need the switch. Two
and you could perhaps get by with some type of toggle switch
(ON-OFF-ON).
It also would depend on whether any of them would be balanced
inputs.
Mine is based on a Greyhill switch, I think. It was a surplus Sonic
Frontiers part that I had picked up at one of their "Garage Sales".
(Works okay.)
Erik
I have been thinking quite a bit about attenuation, and feel like a "switched relay" solution may be good. I am thinking about using a single-wafer switch of maybe 12 or more positions, that would drive four sets of relays from each position - in parallel. This way the switch would not have to be of signal quality, just good enough to turn on a relay. Also synchronising four sets of resistors will be easy, because they are relay driven. This can be repeated for P3 and P4, while P5 can be implemented using a set of only two relays from each position. Another benefit is that all the resistors can be placed on a board, instead of jerry-riged to the switch. What do you guys think? Also, what is the difference between BOSOZ and x-BOSOZ?
amo said:
x-BoSoZ is basically a BoSoZ, BUT.... with X-feedback employed to the original Bosoz circuit. X-feedback was patented and invented by Mr. Pass, and it basically feeding + output to - input... more or less like that.
If you want to see the x-Bosoz, try Henrik's X-Bosoz:
http://www.diyaudio.com/forums/showthread.php?postid=67322#post67322
Mad_K has also tried Henrik's circuit, and he seemed well satisfied with the modification.
Cheers,
Grayhill input selector
I was searching for a good input selector other then the DACT CT4. I have found at digikey a Grayhill selector GH7104-ND. This selector has 2 poles, 2 decks and 6 positions per pole. Does this mean that it is an equivalent selector as a single deck 4 pole?
Can I use this selector for the BOSOZ. The first deck with 2 poles will change the +In and -In and the second deck will change the same for the other channel.
Other suggestions?
George
I was searching for a good input selector other then the DACT CT4. I have found at digikey a Grayhill selector GH7104-ND. This selector has 2 poles, 2 decks and 6 positions per pole. Does this mean that it is an equivalent selector as a single deck 4 pole?
Can I use this selector for the BOSOZ. The first deck with 2 poles will change the +In and -In and the second deck will change the same for the other channel.
Other suggestions?
George
I have no answer to youre quest. above, but wanted to add, what would be considered a transformer "upgrade"? I've searched and read various things about higher current transformers sounding better, ect. forgive my ignorance on this, im learning alot, but am totally confused about the transformers.
Parts
I've been reading up on this topic for quite a while. Here are my thoghts on parts. I've got the BOSOZ working, but have not listened to it seriously, I'm still fitting everything into the case and trying to find some switches.
The standard 750 ohm resistors get hot. Its not a problem, but you could spend extra money and use TO-220 style thick film resistors with heat sinks. These weill take up more room on the board than the standard resistors, and are much more expensive.
http://dkc3.digikey.com/PDF/T033/0812.pdf
I used MUR820 high speed rectifier diodes in the power supply (cheap but good). Am using 2 power supplies instead of one, separate power supplies for each channel.
I used two Plitron transformers, one for each channel. This could be considered a transformer upgrade. (See www.plitron.com). Plitron just raised their prices.
I used solid silver wiring for the signal path, some silver plated wiring in other areas; copper for the power supply.
I am doing relay switching of inputs using NAIS DS series relays.
http://www.naisweb.com/e/relaye/mech_eng/mech_eng_ds/mech_eng_ds.html
People talk about upgrading the DC blocking capacitors. If you are going to to this (I have not tried it yet) realize that substitute capacitors are very large physically, so save room.
For volume, I am using an stereo ALPs blue volume POT (really a switched attenuator) on each channel. I don't think that these are made in 5k so I'm still trying to tweak the ouput circuit using a 50K ALPs instead of 5K as instructed in the article. I kept the other 3 conductive plastic pots in the circuit.
I've been reading up on this topic for quite a while. Here are my thoghts on parts. I've got the BOSOZ working, but have not listened to it seriously, I'm still fitting everything into the case and trying to find some switches.
The standard 750 ohm resistors get hot. Its not a problem, but you could spend extra money and use TO-220 style thick film resistors with heat sinks. These weill take up more room on the board than the standard resistors, and are much more expensive.
http://dkc3.digikey.com/PDF/T033/0812.pdf
I used MUR820 high speed rectifier diodes in the power supply (cheap but good). Am using 2 power supplies instead of one, separate power supplies for each channel.
I used two Plitron transformers, one for each channel. This could be considered a transformer upgrade. (See www.plitron.com). Plitron just raised their prices.
I used solid silver wiring for the signal path, some silver plated wiring in other areas; copper for the power supply.
I am doing relay switching of inputs using NAIS DS series relays.
http://www.naisweb.com/e/relaye/mech_eng/mech_eng_ds/mech_eng_ds.html
People talk about upgrading the DC blocking capacitors. If you are going to to this (I have not tried it yet) realize that substitute capacitors are very large physically, so save room.
For volume, I am using an stereo ALPs blue volume POT (really a switched attenuator) on each channel. I don't think that these are made in 5k so I'm still trying to tweak the ouput circuit using a 50K ALPs instead of 5K as instructed in the article. I kept the other 3 conductive plastic pots in the circuit.
kevyjo said:
I am also new to this, so here is my very limited understanding of the transformer issue: You need to match the voltage of the transformer to what is specified to make it easier on yourself. The current rating, I think, indicates UP TO how many amps you can draw at the voltage specified. I think the problem with using one that is too small by trying to draw too much current, is that it will start physically vibrating causing the dreaded transformer hum (not to mention not providing enough current when needed). Not sure if there is a problem with using one that is too big, aside from it being a huge waist of money. By having two separate power supplies (4 transformers total), your are, besides many other things, lowering the load on each of the transformers...... I think a really cool upgrade is getting one that is encapsulated in a metal can. Besides looking very good, this prevents stray magnetic field from interfering with other components that are sensitive to this kind of thing. If you will put everything in one chassis, then this is highly recommended.
I read about someone using two 160VA transformers and a 16000mf bank of capacitors, and saying the sound was more "effortless", I have no idea. Would any of the surplus transformers from apexjr. work? www.apexjr.com
It was mentioned in some BSOZ thread that if you use a hugely oversized transformer, it's better to spec it at lower than 60 volts, cause with such a low load there is no voltage drop.
I got the impression that 55 volts would work. The advantge of Plitron is that they make a transformer of this output so you don't have to use 2 Avel transformers per channel (the way NP does it- actually he powers both channels from one supply in his write up)
I got the impression that 55 volts would work. The advantge of Plitron is that they make a transformer of this output so you don't have to use 2 Avel transformers per channel (the way NP does it- actually he powers both channels from one supply in his write up)
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