Yes the audio ground and mains safety ground should go to the same chassis ground point?
I think the main point about that single point earth connection for the chassis earth is to ensure that the connection cuts through the insulating film that develops on the anodized aluminium surface, hence the use of the 'star washer' to bight into the metal surface - the CL-60 connection is then added to this, and fastened by it's own nut/washer, or both of the CL-60s if you're going 'dual mono' - it can get rather confusing at times.
Just wanted to give a shout out to the diy audio store. Ordered the F6 parts kit, J-Fets and PSU last Saturday (6th). Arrived this morning in the UK! I think that's pretty outstanding, considering the estimate was early March.. Thanks very much. Now waiting on Mouser for my solder and PSU parts 
Mind you, I haven't ordered a case yet and the transformer is coming from Toroidy. How long do Toroidy usually take, anyone have any experience?
Mind you, I haven't ordered a case yet and the transformer is coming from Toroidy. How long do Toroidy usually take, anyone have any experience?
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Sorry guys and gals, yet more banal questions! As I’m in the U.K. I can’t order the back panel parts kit alone as the price isn’t above $200.
Could I ask what length of M3 bolts do I need and size of M3 standoff’s please? Any links to the best place to get them would be appreciated too.
As a complete noob, I also need hook up wire. So suggestions and links again would be most welcome. Thank you for all your help so far.
The 4U Deluxe case has been ordered now, so just these final few bits and I should be sorted... hopefully!
Could I ask what length of M3 bolts do I need and size of M3 standoff’s please? Any links to the best place to get them would be appreciated too.
As a complete noob, I also need hook up wire. So suggestions and links again would be most welcome. Thank you for all your help so far.
The 4U Deluxe case has been ordered now, so just these final few bits and I should be sorted... hopefully!
Cooler King,
My M3 bolts and standoffs are you referring to the parts needed to fix the PCB and MOSFETs to the heat-sink?
For amplifier projects I have used 6mm or 8mm brass standoffs - one end should be male, one end female (male female type). Regarding the M3 bolts, most of the times I use 6mm bolts for fixing the PCB to the standoffs, and for holding the MOSFETs to heat-sinks usually 8-10 mm bolts. It's also good to have a washer on the MOSFET to have pressure over a wider area. You can get all such hardware (bolts, standoffs, washers) online on Amazon. M3 bolts are available at Element14 (Farnell) too.
Hope this helps and please let us know if you have any questions.
My M3 bolts and standoffs are you referring to the parts needed to fix the PCB and MOSFETs to the heat-sink?
For amplifier projects I have used 6mm or 8mm brass standoffs - one end should be male, one end female (male female type). Regarding the M3 bolts, most of the times I use 6mm bolts for fixing the PCB to the standoffs, and for holding the MOSFETs to heat-sinks usually 8-10 mm bolts. It's also good to have a washer on the MOSFET to have pressure over a wider area. You can get all such hardware (bolts, standoffs, washers) online on Amazon. M3 bolts are available at Element14 (Farnell) too.
Hope this helps and please let us know if you have any questions.
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Cooler King,
Some examples and links:
Machine Screws/Bolts A2 Stainless Steel Pozi Pan Head Mch Screw M3 3mm x 6mm (Pack of 100): Amazon.co.uk: DIY & Tools
sourcing map M3 x 8mm Carbon Steel Phillips Pan Head Machine Screws Bolts Combine with Spring Washer and Plain Washers 50pcs: Amazon.co.uk: DIY & Tools
3mm Machine Screws/Bolts M3 x 10mm A2 Stainless Steel Pozi Pan Head Mch Screw (20 Pack) Free UK Delivery: Amazon.co.uk: Business, Industry & Science
Machine Screws/Bolts A2 Stainless Steel Pozi Pan Head Mch Screw M3 3mm x 10mm (Pack of 100): Amazon.co.uk: DIY & Tools
Yibuy 50 x Male Female PCB Thread Brass Standoff Pillars Standoff Spacers M3 8mm+6mm: Amazon.co.uk: Kitchen & Home
Some examples and links:
Machine Screws/Bolts A2 Stainless Steel Pozi Pan Head Mch Screw M3 3mm x 6mm (Pack of 100): Amazon.co.uk: DIY & Tools
sourcing map M3 x 8mm Carbon Steel Phillips Pan Head Machine Screws Bolts Combine with Spring Washer and Plain Washers 50pcs: Amazon.co.uk: DIY & Tools
3mm Machine Screws/Bolts M3 x 10mm A2 Stainless Steel Pozi Pan Head Mch Screw (20 Pack) Free UK Delivery: Amazon.co.uk: Business, Industry & Science
Machine Screws/Bolts A2 Stainless Steel Pozi Pan Head Mch Screw M3 3mm x 10mm (Pack of 100): Amazon.co.uk: DIY & Tools
Yibuy 50 x Male Female PCB Thread Brass Standoff Pillars Standoff Spacers M3 8mm+6mm: Amazon.co.uk: Kitchen & Home
What power supply board have you selected Cooler King?
For fixing the power supply PCB to the bottom of the chassis I prefer to use 10mm standoffs, both side female; however 8mm tall and male-female will also work. I prefer to make the holes on the bottom of the chassis slightly bigger than M3 bolts so that there is a little wiggle room, and then run the screws through the chassis floor and connect with the threads of the standoff. It saves me the burden of tapping very accurate holes on the chassis floor.
On the top side, the PCB can be fixed with screws if top side of the standoff is female, and with nuts if it is male.
P.S. If your chassis is coming with perforated bottom sheet, then no worries around drilling holes in the chassis floor.
For fixing the power supply PCB to the bottom of the chassis I prefer to use 10mm standoffs, both side female; however 8mm tall and male-female will also work. I prefer to make the holes on the bottom of the chassis slightly bigger than M3 bolts so that there is a little wiggle room, and then run the screws through the chassis floor and connect with the threads of the standoff. It saves me the burden of tapping very accurate holes on the chassis floor.
On the top side, the PCB can be fixed with screws if top side of the standoff is female, and with nuts if it is male.
P.S. If your chassis is coming with perforated bottom sheet, then no worries around drilling holes in the chassis floor.
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Funnily enough I've got some 10 mm standoff's in my checkout basket. The psu is the one from here. I've ordered the 4U Deluxe case, so that has the perforated bottom tray. I'm getting the gist of it I think!
Thanks very much for your input, it's greatly appreciated!
Just need to source some wire for the internals..
Thanks very much for your input, it's greatly appreciated!
Just need to source some wire for the internals..
For the power supply connections 12-16 gauge copper wire should be sufficient.
For connection to the speaker terminals, probably 18 ga is good enough. For input (connecting to RCA sockets) you can use the same or something thinner (any good quality copper cable will work). I use Mogami W2314 miniature instrument cable for input connections nowadays (I have some on hand), heard from others that Belden instrument cable is good too.
For connection to the speaker terminals, probably 18 ga is good enough. For input (connecting to RCA sockets) you can use the same or something thinner (any good quality copper cable will work). I use Mogami W2314 miniature instrument cable for input connections nowadays (I have some on hand), heard from others that Belden instrument cable is good too.
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Looking for a gain device between DAC and F6
I built an IRFP240-based F6 using to "Store" boards a year or so ago. Recently to loaned it to a friend to evaluate with some 87dB speakers. The F6 is driven directly from a DAC with a maximum out level of around 2Vrms, which is not enough to drive the F6 to clipping with only 5X gain.
What simple gain 2X-3X device could he use between his DAC and the F6, without introducing excessive distortion, noise, and cost?
I have encountered the same problem with some other low-gain amps (eq. F7) which I wanted to drive directly from a DAC, not using any preamplifier.
I built an IRFP240-based F6 using to "Store" boards a year or so ago. Recently to loaned it to a friend to evaluate with some 87dB speakers. The F6 is driven directly from a DAC with a maximum out level of around 2Vrms, which is not enough to drive the F6 to clipping with only 5X gain.
What simple gain 2X-3X device could he use between his DAC and the F6, without introducing excessive distortion, noise, and cost?
I have encountered the same problem with some other low-gain amps (eq. F7) which I wanted to drive directly from a DAC, not using any preamplifier.
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I was wondering about that very same thing, Lynn.
What attracted my attention was the various optional input stages that Mark Johnson has developed for the M2x amplifier - I had the idea that on the version 7 (IPS7), perhaps the board could be modified to allow the output IC to be configured for a 6dB gain instead of the present unity gain - these boards are quite small and fitting them as a substitute for the present input jfets in the F6 would be a bit of a 'hack' but ... - when the boards arrive, I will have a better idea of the options.
I have the 6/24 electronic Xover kit here awaiting assembly and it wouldn't be too hard to add a 6 - 10dB gain stage based around an IC chip to this unit too - I do like the flexibility of these optional input buffers and the clever thinking to develop them.
What attracted my attention was the various optional input stages that Mark Johnson has developed for the M2x amplifier - I had the idea that on the version 7 (IPS7), perhaps the board could be modified to allow the output IC to be configured for a 6dB gain instead of the present unity gain - these boards are quite small and fitting them as a substitute for the present input jfets in the F6 would be a bit of a 'hack' but ... - when the boards arrive, I will have a better idea of the options.
I have the 6/24 electronic Xover kit here awaiting assembly and it wouldn't be too hard to add a 6 - 10dB gain stage based around an IC chip to this unit too - I do like the flexibility of these optional input buffers and the clever thinking to develop them.
