Building a symmetrical PSU B1 buffer

Can anyone point me to the BOM for the Hotrodded DCB1.

The thread has got so long that it takes forever to read through all the catty comments.

I'm making board changes anyway so any component changes will be minor.

First off I'm changing the relay drive to a TO220 TIP122, not for any other reason than I've got a pile of TIP122's.

I did ask the question. I'm going to use BYW80-150 purely because I've got a pile of them too. They do seem better in every respect than the MUR840 anyway.
 
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First point me which one schematic you refer to.

Hypnotize-2 Dated 13/May/2010


If this isn't the best option then please advise.

I've already got a BRILLIANT B1 and I'm just experimenting to see how much better I can get.

I'm going to need the Obbligato 10uF output caps though as I'm driving the DC coupled Aleph 4.
 

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TIP122 is a Darlington like BC517, I hope it will work the same but its never tested there before. If the relay won't click, or will emit mechanical ''chatter'' noises, use BC517.
Here is the BOM of the Hypno2 Hot-Rod ''Blue'', that one had either 2x47R or a single 5W 10R positions, should be the one you are looking for?
 

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Hypnotize-2 Dated 13/May/2010


If this isn't the best option then please advise.

I've already got a BRILLIANT B1 and I'm just experimenting to see how much better I can get.

I'm going to need the Obbligato 10uF output caps though as I'm driving the DC coupled Aleph 4.

Its the right option, only ground the rest position of the relay as we did in a next batch of PCBs. Its better for noise immunity on the signal cables when high impedance is driven. Also use 200-300mA standing current, some heat but you will appreciate the sonics. A couple of 6.8R 5W will get you there. Using the output capacitors isn't best for signal purity, but if your Aleph does not have DC sensing output relay protection, you do very well to use output capacitors. Its for the loudspeakers safety.
 

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I opted to have NO protection on the Aleph 4, it relies purely on the solid design. And I have shorted the ouitputs without any damage to the amp - Well done Nelson on the design.

I am therefore stuck with having to have the output caps but I do have the excellent Obligatto 10uF PIOs from my B1.

I've got some nice 2E heatsinks that will ditch the Power FET heat but I'll need to mount the IRFP's remotely.

As far as I can recall this doesn't have a detrimental effect as long as the gate resistors are close to the FETs.

I'll work with 300mA if that is best ??

Will the 2SK170s need heatsinks at this current ?
 
The DC blockers can be fitted at the output of the Source or at the input of the Receiver.

Since your Alephs could be used with a few different Sources, I'd suggest you fit the DC blockers to the Alephs.

You could go further and have two sets of inputs. One as currently, DC coupled.
The second set would have the DC blocking cap between this "extra" input and the normal input.

That gives you a choice, whenever you change equipment, to go for fully DC coupled or for DC blocked.
 
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I opted to have NO protection on the Aleph 4, it relies purely on the solid design. And I have shorted the ouitputs without any damage to the amp - Well done Nelson on the design.
I am therefore stuck with having to have the output caps but I do have the excellent Obligatto 10uF PIOs from my B1.
I've got some nice 2E heatsinks that will ditch the Power FET heat but I'll need to mount the IRFP's remotely.
As far as I can recall this doesn't have a detrimental effect as long as the gate resistors are close to the FETs.
I'll work with 300mA if that is best ??
Will the 2SK170s need heatsinks at this current ?

Hmm, remotely mounting the MOSFETs and relying only to gate resistors proximity bears a logical chance, but I would use oscilloscope to confirm that the rails are oscillations free. The regulators are faster than most amps you see. Some go even higher, but 300mA is good enough. You will judge your roof by the heat you can afford on the final build's sink by experiencing it. K170s need no sinks. If one rail goes out in DCB1's life, or a source gives DC to it, there will be DC on its output, so there you must have at least one capacitor in the chain since you got no power DC protection. The relay is there not so much for muting powering up pops but to prevent a DC rise and fall circle while DCB1 is powered down by the way. You may consider avoiding it all together if you will never hook it up to a DC coupled amp. Since you are making your own board that is. Else do as Andrew wrote. Make it two outputs, and have DC and AC RCAs.
 
Hmm, remotely mounting the MOSFETs and relying only to gate resistors proximity bears a logical chance, but I would use oscilloscope to confirm that the rails are oscillations free. The regulators are faster than most amps you see. Some go even higher, but 300mA is good enough. You will judge your roof by the heat you can afford on the final build's sink by experiencing it. K170s need no sinks. If one rail goes out in DCB1's life, or a source gives DC to it, there will be DC on its output, so there you must have at least one capacitor in the chain since you got no power DC protection. The relay is there not so much for muting powering up pops but to prevent a DC rise and fall circle while DCB1 is powered down by the way. You may consider avoiding it all together if you will never hook it up to a DC coupled amp. Since you are making your own board that is. Else do as Andrew wrote. Make it two outputs, and have DC and AC RCAs.

Its a weigh up situation.

Keeping the board as-is and fitting heatsinks.

I can keep the FETs cool with four of these sinks but I cant keep the layout if I use them.
 

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The board I'm playing with is an exact copy of the DCB1-Blue with changes only to the relay driver at the moment.

I might play with keeping the board layout - as it's a proven design, and just mount two of the heatsinks horizontally above the MOS-FETs .

Until I start playing I've got little idea as to how much heat I am trying to shed.
 
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I consider there are 4 design situations to be taken into account.

Normal operation and normal temperatures.
Highest mains voltage and slightly above normal temperatures.
Highest mains voltage and shorted output, circuit survives without damage.
Normal operation and zero load current, circuit survives without damage.