Salas hotrodded blue DCB1 build

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I've been asking around about that too. The suggestions I've had is to put it on the input of the F-5. I would prefer to leave the F-5 as is, and put it on the output of the B-1, although it wont be exactly DC then, which was the point, but I like a little insurance. The person who was commenting seemed to suggest it would be better on the input of the F-5, I'm not clear on why, so I continue to ask around. Nelson apparently chose to put the caps in the B-1 (standard non DC version of course) for what ever reason.

Russellc

What is the performance difference beyond physical location? None. I would stick 4 output RCAs in the DCB1's box, two straight, two C coupled. Choice for any amp or worry.
 
When I build my DCB1 to make things "safe" I will need to install a capacitor on the input of my yet to be built F5 [still waiting for the heatsinks; 6 weeks & counting] What value cap do people recommend and would it make any difference if I installed one on the F5 input or the output of the DCB1? I am reading through all relevant threads so hope I havent missed this bit of info.
Thanks.http://www.diyaudio.com/forums/images/smilies/confused.gif

I had also considered this and will be re-installing the input cap on my NCC poweramp. Something like a 3.3 - 10uF polyprop would do.

I recommend the K4700 speaker protection kit from Velleman. Very effective and no loss to sound quality as far as I can tell:

ESR Electronic Components - Velleman Kits

Decent kits are also avilable from SKA Audio and ebay -

SKA sponsored Audio Forum - Products

Stereo Speaker protection kit components DIY NEW A16 on eBay (end time 26-Aug-10 10:15:24 BST)

Speaker protection circuit dual mono 30A BTL /stereo ! on eBay (end time 03-Sep-10 15:07:48 BST)
 
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Salas; thanks for the suggestion regarding having dual outputs on the DBC1. I will do it that way.

Richlund; my F5 will initially have a common supply so I will use one Velleman kit; but who knows if I really like it I may well go dual mono.

A question for AndrewT; do you still suppl matched 2SK170's?

Keith.
 
Salas; thanks for the suggestion regarding having dual outputs on the DBC1. I will do it that way.

Richlund; my F5 will initially have a common supply so I will use one Velleman kit; but who knows if I really like it I may well go dual mono.

A question for AndrewT; do you still suppl matched 2SK170's?

Keith.

I recommend the last DC protection on that list, from eBay seller Jim's Audio. It can be supplied from 1x transformer for single case use, but is dual mono too, for down the road.... I have used this guy's stuff before and it is very well put together indeed.
 
If the audio quad JFETs are very closely matched per pair its good for offset, and I recommend best match possible especially in the Blue. If tight, an average DVM will not be dependable to show 2 times which one is slightly less Idss anyway, and if you blow over or touch they will jitter. But if they have a slight and reliable difference, use the lesser one for inner position per pair.

Thanks for making that clear. I had not understood that correctly. And thank you for all that you have done to help make this project a reality. I have enjoyed building the DCB1 and am impressed by how good this preamplifier is. It fits in perfectly between my DAC and electronic crossover. I am a bit surprised to find out that the DIY side of doing this is as fun as it has been.
 
What is the performance difference beyond physical location? None. I would stick 4 output RCAs in the DCB1's box, two straight, two C coupled. Choice for any amp or worry.

Hi Salas -

Excuse the dumb question... so you're saying just split the outputd from the 'Blue' - 1st direct to RCAs and 2nd through Capacitor to separate RCAs??? Am I understanding that correctly???
 
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I had also considered this and will be re-installing the input cap on my NCC poweramp. Something like a 3.3 - 10uF polyprop would do.

I recommend the K4700 speaker protection kit from Velleman. Very effective and no loss to sound quality as far as I can tell:

ESR Electronic Components - Velleman Kits

Decent kits are also avilable from SKA Audio and ebay -

SKA sponsored Audio Forum - Products

Stereo Speaker protection kit components DIY NEW A16 on eBay (end time 26-Aug-10 10:15:24 BST)

Speaker protection circuit dual mono 30A BTL /stereo ! on eBay (end time 03-Sep-10 15:07:48 BST)

To make the protection kit recommendations complete:

Aussie Amp´s LSP-1 ;)


Cheers,
Oliver
 
Irfp240

Looking at the Blue Board their is no indication as to where the N-Channel and P-Channel are placed.


The only indication of polarity is the V+ and V- printed on the board next to 3 holes marked "G" and 10 20 30 and J2.

Is this the indication to place the N_Channel mosfets on the V- and the P_Channel on the V+ side of the Blue Board?
 
Looking at the Blue Board their is no indication as to where the N-Channel and P-Channel are placed.


The only indication of polarity is the V+ and V- printed on the board next to 3 holes marked "G" and 10 20 30 and J2.

Is this the indication to place the N_Channel mosfets on the V- and the P_Channel on the V+ side of the Blue Board?

It gives the numbers IRFP 9240 for P channel and IRFP240 for the N channel (note the number 9 in the middle of the P channel number!)

Also, yes, the P channel is on the + side of the reg.
 
May I ask why if they are not going to be connected simultaneously? The other end of the cap would hang off disconnected
I would not leave the other end disconnected. I would use a 1M0 or 2M2 to DC reference the Hot to audio ground.

If I have two outputs, one AC coupled and one DC coupled, I would be very tempted to try a bass or sub-bass amp/speaker on the DC coupled output and reserve the AC coupled output for Mid and/or Treble amp/speaker. That way I can put in a low value, high quality, coupling/DC blocking cap that is affordable.
 
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J1 is used always. J2 is used always. The ''NOTE'' resistor is replaced with a jumper when having a 12V relay as it is explained under ''NOTE:Replace...'' on the board itself. If with 5V relay its 2 600R resistors side by side.

There is no build ''manual'' that I am aware of.