[mboxler]

Here's a thought, and forgive me because I don't have a board or chassis to check with. But can the PS Board be rotated 90 or 180 degrees to give more clearance to the IEC connections?

Good thought, but case is too small for 90 degree and 180 degree would make the other wiring almost impossible.  However...a 5 or 10 degree pivot might move the offending cap enough from the IEC to eliminate the grinding I did to shorten the disconnect.  I didn't want to drill any more holes...but.

Neville, bummer on the flag disconnects.  Even with a minor PS adjustment, a regular disconnect will be tight.  When this is over, I think I'll recommend to Tom to supply the disconnects with the kit.

Regarding the toggle switch...is your issue which pins/connectors to use, or how to make those connections?

Mike

[vinylb]

Here's a thought, and forgive me because I don't have a board or chassis to check with. But can the PS Board be rotated 90 or 180 degrees to give more clearance to the IEC connections?

Barry thats exactly what I am doing now....finding a better location for it. So far it appears best location in terms of wiring is to have the ps board
adjacent to transformer and then the amp board between ps board and rear plate.  I could move the ps board (in its current location) about 2 inches further away from rear plate but the caps still prevent easy access to it. Rotating so caps to the left are better but you have a lot of wiring going across. So its one or the other

[justinm]

Good thought, but case is too small for 90 degree and 180 degree would make the other wiring almost impossible.  However...a 5 or 10 degree pivot might move the offending cap enough from the IEC to eliminate the grinding I did to shorten the disconnect.  I didn't want to drill any more holes...but.

Neville, bummer on the flag disconnects.  Even with a minor PS adjustment, a regular disconnect will be tight.  When this is over, I think I'll recommend to Tom to supply the disconnects with the kit.

Regarding the toggle switch...is your issue which pins/connectors to use, or how to make those connections?

Mike

How about soldering wires directly to IEC at an angle?

[vinylb]

Justin I thought about that but went for the new layout.




Those rear "screws" are really a pain. I only have the size a notch or two up from it.

I am confused about how to wire the the toggle, 3 rows of 2 lugs or 2 rows of 3 lugs......one side has 1,2 & 3 on it. Toggle is either on or off so I don't understand the middle lugs unless I should be looking at it from 2 rows and 3 lugs.

Was hoping to get this done tonight because of travel over next few days....oh well it will have to wait until I return.

[mboxler]

Think of it as two rows of two lugs (the top two pairs of lugs).  Wire the top  lug on one side of the switch to pin 2 of J1, wire the middle lug on that same side of the switch to pin 3 of J1. Wire the top and middle lugs of the other side the same way to pins 2 and 3 of J2.  When the toggle is down (RCA), the top and middle lugs on both sides of the switch are closed (ON).  Connect a mult-meter to them...you should get 0 ohms.  This connects pins 2 and 3 on the amp's J1 and J2, putting it into RCA mode.  When the toggle is up (BAL), the middle and bottom lugs are closed (ON).  However, the top and middle lugs (where you have connected the wires) are open (OFF).  The multi-meter will show no connection...pins 2 and 3 are not connected...the amp is in BAL mode.  The bottom two lugs on the switch are not used (see pictures).

Tom could have just used a 4 pin switch, causing both sides to be open or closed, and reversed the inputs on the back.  Then when the switch were flipped up, a normal ON position, the amp would be in RCA mode.  I assume the thinking was that the switch could be mounted upside down, causing damage to the amp.

Mike

[Æ]

Radioshack and HDepot dont carry any right angle connectors. What has become of RShack?

I bought some at my local ACE Hardware store.

[Æ]

bummer on the flag disconnects.

I bought some at my local ACE Hardware store.

[Barry_NJ]

Justin I thought about that but went for the new layout.

The only thing that makes me nervous about that layout is the lack of venting under and over the PS Board as there would be with the stock layout(?)

[mboxler]

I bought some at my local ACE Hardware store.

Yea...they are everywhere (almost).  The point I want to make to Tom is that he probably gets them for pennies each (I saw 1000 for $149 on EBay).  Most people don't have them in their stash at home, and the cost and inconvenience of tracking some down can be frustrating.  With the flag disconnects, the original layout works very well (I agree on the cooling issue), as long as you don't solder yourself into a corner. 

[vinylb]

Thx for heads up on Ace, will check when I get back. As for heat
I am planning on adding a 12v fan later on. Will test it before going with fan.

As much as I like case I too have found it very frustrating and plan to send tom my recommendations from a noob point of view.

[.Marcus.]

Hello,
i want to share some possible recaping for everbody who have fun to experience with tweaking the  SDS board. The caps are all placed in the input stage of the board.

On the right side there are two smd caps which are using as PS caps for the input stage circuit, in the middle there are two smd caps which are using as bootstraping / filter of the input stage.

I changed the caps to panasonic FC caps. The recap is no game changer but for me it sounds more "powerful" / "muscial".

Note : Please double check the polarity, there is a small dot on the assembly printed of the pcb, they marks the postive side of the caps.




Regards
Marcus

[matt_garman]

Mike, did you use thermal paste on the underside of the "pontoons"? I am referring to the heatsinks that almost touch the bottom of the enclosure.
I could have it touch if I add a washer or two but not sure if there will be any benefit to it.

Take a look at my build back on page 152.  I've been having some overheating problems with my amp.  However, I'm using a significantly smaller enclosure, plus a switch-mode power supply that is less efficient than the default linear PS (i.e. puts out more heat).

The first time I put my system together, I didn't have a good mating between the chassis and the "pontoons" of the SDS-470.  The system would overheat quite readily.

I then rebuilt the system, after using a grinding bit on the standoff holes (to effectively "countersink" them), and also put some washers on the standoff screws.  This ensured that my pontoons were fully mated to the chassis and I could apply a lot of pressure to them.  I also put some CPU thermal paste between the chassis and heatslugs.

I thought I was in the clear, as I could only get the unit to overheat if I wrapped it in a fleece blanket... but we've had a string of unseasonably warm weather here in Chicago.  And my wife said that during the day, it got to be around 80 deg F in the house, and the amp started overheating.

Now Tom wants me to drill some ventilation holes in the bottom of my chassis.  I haven't had a chance to do that.

Despite these problems, I have a fully-built SDS-470 on order.  I don't expect to have any heat problems, since it will be a much bigger chassis with a more efficient (i.e. less internal heat) power supply.

Anyway, based on the issues I've had, I would definitely use thermal paste between the chassis and pontoon heatslugs.  I don't know if Tom does on his prebuilt ones or not.  But I can't imagine doing so would negatively affect anything.

[roymail]

Matt, have you tried leaving the top off or using a heavy screen type top or adding a small fan to the mix?

Your layout is nice, just needs adequate venting.  Thanks!

[matt_garman]

Matt, have you tried leaving the top off or using a heavy screen type top or adding a small fan to the mix?

I have not tried either of those, but I'm quite confident that they would solve the problem.  For a while there, whenever the overheating issues started, I would pull the top off so I could use my temperature gun.  But within seconds of pulling off the top, the issues went away.  Based on that alone, I'm sure having no cover or a mesh/screen cover would definitely help.  But I'd really like to keep the case as-is, if possible.  My next plan is to try Tom's suggestion of adding vent-holes to the bottom.

I've thought about using a fan, and really don't want to go there.  From my experience with computers, small fans need to spin rapidly to actually move any air.  And given the size of my case, I'd have to use a small fan.  If I had room for a decent-sized fan (92mm or bigger), I could get one that is slow enough to be silent, yet still move a reasonable amount of air.

[vinylb]

Take a look at my build back on page 152.  I've been having some overheating problems with my amp.  However, I'm using a significantly smaller enclosure, plus a switch-mode power supply that is less efficient than the default linear PS (i.e. puts out more heat).

The first time I put my system together, I didn't have a good mating between the chassis and the "pontoons" of the SDS-470.  The system would overheat quite readily.

I then rebuilt the system, after using a grinding bit on the standoff holes (to effectively "countersink" them), and also put some washers on the standoff screws.  This ensured that my pontoons were fully mated to the chassis and I could apply a lot of pressure to them.  I also put some CPU thermal paste between the chassis and heatslugs.

I thought I was in the clear, as I could only get the unit to overheat if I wrapped it in a fleece blanket... but we've had a string of unseasonably warm weather here in Chicago.  And my wife said that during the day, it got to be around 80 deg F in the house, and the amp started overheating.

Now Tom wants me to drill some ventilation holes in the bottom of my chassis.  I haven't had a chance to do that.

Despite these problems, I have a fully-built SDS-470 on order.  I don't expect to have any heat problems, since it will be a much bigger chassis with a more efficient (i.e. less internal heat) power supply.

Anyway, based on the issues I've had, I would definitely use thermal paste between the chassis and pontoon heatslugs.  I don't know if Tom does on his prebuilt ones or not.  But I can't imagine doing so would negatively affect anything.

Matt, sorry to hear you still having problems. I recall reading your posts earlier but thought you had it all sorted out. Are you able to get a reading of the temps below the ps board? If so, what are they?

Nice to hear somebody also implemented thermal paste below the pontoons. Do you have any temp or data to indicate how beneficial thermal paste and mating the pontoons with the chassis was?  Looking at the screws attaching the pontoons to the amp board's heatsink does not look like there is enough "bonding" to allow sufficient distribution of heat from board heatsink to pontoons. But I could be wrong. Any advice you have will be appreciated.

If Tom, wants you to drill holes/air vents in the chassis, how would you do it? I guess I am a ludite when it comes to this unless you have the tools create rows where heat escapes. I own bare minimal tools although I sure wish I had a hardware store in my store room, thats not going to happen.

Mike, I see on ebay, a seller selling that lot of flag disconnects, but I really dont want 1000' of them I emailed another seller selling lot of 20 for $6 if they would fit IEC. Waiting to hear back from them. After driving nearly 650 miles, one way, I don't have the energy to drive to ACE, at least not today or tomorrow.

.Marcus, nice layout with double decker amp boards Reminds me of the bus I use to take when I was a young lad, but that was in a different country and era. What values and make are the caps you replaced with ? From what you said, you found it powerful and musical, can you elaborate a little on that ?

[matt_garman]

Matt, sorry to hear you still having problems. I recall reading your posts earlier but thought you had it all sorted out. Are you able to get a reading of the temps below the ps board? If so, what are they?

No, things are packed in there too tightly to get any temperature reading under either the PS or amp board.  IOW, I'd have to completely dis-assemble everything to take that kind of reading.

Nice to hear somebody also implemented thermal paste below the pontoons. Do you have any temp or data to indicate how beneficial thermal paste and mating the pontoons with the chassis was?  Looking at the screws attaching the pontoons to the amp board's heatsink does not look like there is enough "bonding" to allow sufficient distribution of heat from board heatsink to pontoons. But I could be wrong. Any advice you have will be appreciated.

Unfortunately, I do not have any hard data on this.  My temperature gun was a gift that I received after I had already re-mounted the board with better mating and the thermal compound.

All I can say, in a very informal sense, is that with the poor mounting and no thermal paste, the amp would readily overheat on its own.  And with the improved mounting and thermal paste, it would not overheat unless wrapped in a fleece blanket or the ambient temperature in the house was over 80 deg F.

But, as you can see, I changed two variables (better mating, thermal paste), so it's impossible to say how much each contributed to the better cooling.

If Tom, wants you to drill holes/air vents in the chassis, how would you do it? I guess I am a ludite when it comes to this unless you have the tools create rows where heat escapes. I own bare minimal tools although I sure wish I had a hardware store in my store room, thats not going to happen.

I never posted pictures of the top of the case, but that already has vent holes.  I did take pics of the top cover (with the vent holes) and sent them to Tom.  He said they are adequate, but I should add holes to the bottom of the chassis.  Since it's the bottom, where I don't care about looks, I'm just going to take the whole thing apart, and go to work with my drill.  I don't really have any plan; I'm just going to do it by feel (unless someone suggests a better method!).

[corndog71]

This all makes me glad I went with the bigger case.

[mboxler]

This all makes me glad I went with the bigger case.

I'm sure the details are buried in this thread somewhere, but what size and brand of case did you use? 

Thanks, Mike

[matt_garman]

I'm sure the details are buried in this thread somewhere, but what size and brand of case did you use?

The one I used I found on ebay, and it continues to re-appear (presumably the seller has a lot or is making them himself): "#### HiFi Audio DIY Aluminum Chassis Aluminum Case B", seller ericyam.

Dimensions:
External: W 200 mm x H 85 mm x D 330 mm = 7.9" x 3.3" x 13"
Internal: W 175 mm x H  63 mm x D 320 mm = 6.9" x 2.5" x 12.6"

See pictures of my build back on page 152.

By the way, the ebay listing has a picture where you can see what the top vent holes of my case look like.

[.Marcus.]

.Marcus, nice layout with double decker amp boards Reminds me of the bus I use to take when I was a young lad, but that was in a different country and era. What values and make are the caps you replaced with ? From what you said, you found it powerful and musical, can you elaborate a little on that ?

Hi Vinylb,
you are a funny guy by thinking about double decker bus If the double decker amp play they take me away also 

Original PS Caps are 10µF / 16V, i had replace them with 470µF / 25V 

Original Bootstrap / Filter Cap is 220µF / 4V, i had replace them with 220µF / 10 V.
I recommended to keep the capacity value of the Bootstrap / Filter Cap.

Please find some additional information about the input stage here :

http://www.thatcorp.com/datashts/Galo_THAT_Line_Dr_%20Rx.pdf

Especialy Page E13 / E14 describe which componets are used for the test circuit.

btw.. i will change the 100 Ohm resistors of the signal input path with some higher grade (e.g. TX Foli) stuff.

For me the bass has more bunch and the sound are more accurate. The music plays more free.

Regards
Marcus