Caps after regulator
I have built the B1 and recently added my version of σ11 regulated linear power supply to it.
Would you share your thoughts on the C1 and C2 (currently Mundorf MLytic AG 20K each)? Could their high capacity cause any harm in case of a good power supply before them or I should not be bothered?
Btw replacing my previous LT1084 based LPS with the σ11 shunt regulator, did not make any difference to my ears. That is why I am wondering if the big MLytics are messing something or that is just the limit of B1.
I have built the B1 and recently added my version of σ11 regulated linear power supply to it.
Would you share your thoughts on the C1 and C2 (currently Mundorf MLytic AG 20K each)? Could their high capacity cause any harm in case of a good power supply before them or I should not be bothered?
Btw replacing my previous LT1084 based LPS with the σ11 shunt regulator, did not make any difference to my ears. That is why I am wondering if the big MLytics are messing something or that is just the limit of B1.
Hello everyone,
I'm planning to build a B1 preamp as well. Unfortunately I'm not that deep into electronics and this would just be my second hifi electronics diy project. My first was a SymAsym poweramp which I plan to combine with the B1. My goal is a build that has at least four inputs (preferably more) and an automatic volume control. My first step would be to setup the basic build on a wooden board and than add everything I want step by step before I put it into its final compartment.
So, here are my first questions:
1. The only source of a B1 PCB with matched transistor I found here: PassDiy. As far as I see this is the original PCB with only 2 inputs, right? Is there any comparable alternative that would suffice my requirement of the number of inputs? Btw I am from Germany.
2. Which would be the best choice for a high quality motorized poti with a simple volume control?
3. Is there a source of good volume/source selection knobs?
4. Is it possible to have balanced as well an unbalanced inputs and outputs? I think I saw preamps that combine both.
I'm grateful for any helpful information!
I'm planning to build a B1 preamp as well. Unfortunately I'm not that deep into electronics and this would just be my second hifi electronics diy project. My first was a SymAsym poweramp which I plan to combine with the B1. My goal is a build that has at least four inputs (preferably more) and an automatic volume control. My first step would be to setup the basic build on a wooden board and than add everything I want step by step before I put it into its final compartment.
So, here are my first questions:
1. The only source of a B1 PCB with matched transistor I found here: PassDiy. As far as I see this is the original PCB with only 2 inputs, right? Is there any comparable alternative that would suffice my requirement of the number of inputs? Btw I am from Germany.
2. Which would be the best choice for a high quality motorized poti with a simple volume control?
3. Is there a source of good volume/source selection knobs?
4. Is it possible to have balanced as well an unbalanced inputs and outputs? I think I saw preamps that combine both.
I'm grateful for any helpful information!
GB For Salas I-Select Mesmerize Type input selector and volume control
I-Select will give you the inputs you want. Just bypass the switch on the B1 pcb.
Knobs come in many shapes and sizes (and prices). Check out conrad.de or reichelt.de or ebay. Modushop.biz in Italy do some very nice ones and shipping is not so bad for Germany. You can also buy them from eltim.eu and may combine with other parts to save on shipping.
B1 is single ended only. If you want balanced you could build a BB1 (balanced b1) which simply is 2 b1's, one for each channel. Or you could look at Aleph P1.7, Zen Mod's Pumpkin and many others.
I-Select will give you the inputs you want. Just bypass the switch on the B1 pcb.
Knobs come in many shapes and sizes (and prices). Check out conrad.de or reichelt.de or ebay. Modushop.biz in Italy do some very nice ones and shipping is not so bad for Germany. You can also buy them from eltim.eu and may combine with other parts to save on shipping.
B1 is single ended only. If you want balanced you could build a BB1 (balanced b1) which simply is 2 b1's, one for each channel. Or you could look at Aleph P1.7, Zen Mod's Pumpkin and many others.
Hello everyone,
I got my DCB1 and I-Select last week and started to put them together. Four questions arose so far:
1. When using the "Hot Rod" variant with a 10 Ohm resistor, which parts will need additional cooling? I guess the large MOSFETs IRFP240 and RFP9240, but also the MUR820 diodes and L7812ACV regulator? The regulator has this small "cooling clip" so far.
2. When cooling the parts mentioned above with a 17*10cm aluminum cooler can I also go one step further with the "Hot Rod" by using the 5 Ohm resistors or would this need some kind of active cooling? I don't want to take a risk that the DCB1 will blow up later on.
3. If I use the "Hot Rod" variant with the 10 Ohm or 5 Ohm resistors, do I need a stronger transformer or is the 50Va 2x15V still sufficient?
4. Just to be sure, when using the 7812 regulator I place a jumper over the 600 ohm resistor, right?
Thanks!
I got my DCB1 and I-Select last week and started to put them together. Four questions arose so far:
1. When using the "Hot Rod" variant with a 10 Ohm resistor, which parts will need additional cooling? I guess the large MOSFETs IRFP240 and RFP9240, but also the MUR820 diodes and L7812ACV regulator? The regulator has this small "cooling clip" so far.
2. When cooling the parts mentioned above with a 17*10cm aluminum cooler can I also go one step further with the "Hot Rod" by using the 5 Ohm resistors or would this need some kind of active cooling? I don't want to take a risk that the DCB1 will blow up later on.
3. If I use the "Hot Rod" variant with the 10 Ohm or 5 Ohm resistors, do I need a stronger transformer or is the 50Va 2x15V still sufficient?
4. Just to be sure, when using the 7812 regulator I place a jumper over the 600 ohm resistor, right?
Thanks!
Okay, so I will only place the IRFP240s and RFP9240s on the cooler.
Any thoughts on my other questions?
The transformer needs to be assessed for the continuous DC output current.
A 50VA dual 15Vac has a maximum continuous AC current rating of 50/{15+15} = 1.66Aac
After a capacitor input filter this gives a maximum continuous DC current of ~ 900mAdc
This will run hot and that will have an effect on long term reliability.
I have advised dozens of times that for cool running and long term reliability that only 50% of this DC current capability be used, i.e. ~450mAac
The quick way to arrive at this cool current is 25% of the AC rating, i.e. 25% of 1.667mAac = 417mAdc
A 50VA dual 15Vac has a maximum continuous AC current rating of 50/{15+15} = 1.66Aac
After a capacitor input filter this gives a maximum continuous DC current of ~ 900mAdc
This will run hot and that will have an effect on long term reliability.
I have advised dozens of times that for cool running and long term reliability that only 50% of this DC current capability be used, i.e. ~450mAac
The quick way to arrive at this cool current is 25% of the AC rating, i.e. 25% of 1.667mAac = 417mAdc
Okay, so the 50Va 2x15V transformer is oversized? Still when I use the Hot-Rod variant? What would you say about my second and third questions:
Thanks!
Does mains power enter the enclosure?
Then you NEED the mains PE wire directly and permanently connected to the enclosure.
no, there is no need to connect the Power Zero Volts to the enclosure.
That safety feature will be back at the PSU where you should comply with:
All exposed conductive parts should be connected to the protected chassis.
Hey everyone,
can I use the Vout of my DCB1 Board to power the I-Select board? If so, is there still need to put the caps C1/C2 and IC1 and the Diodes on the I-Select board?
Does anyone know where to get an extending rod for the alps poti? Or is the local hardware store the best place to look?
Thanks
can I use the Vout of my DCB1 Board to power the I-Select board? If so, is there still need to put the caps C1/C2 and IC1 and the Diodes on the I-Select board?
Does anyone know where to get an extending rod for the alps poti? Or is the local hardware store the best place to look?
Thanks
I just bought 6mm diameter brass rod on 'bay. To join it with the pot shaft look for the flexible shaft couplers (for 6mm diameter shafts).
Regards,
Oleg
