[GregVDS]

Thanks AMB,

I checked the spec sheet, I used a kemet tantalum T35 serie, and yes the upside down L is completed by a tiny + near one of the leg. Everything is ok at the moment

Tonight, I finish the PSU I think (heatsink, big caps and toroidal transfo, and cabling). I will maybe go slow, to avoid any stupid errors, as desoldering something gives me nightmares.

I realized I ordered 9 x 330µF nichicon UHE for M³ C7, hence I can have as much as 2970 µF (I know, +- 10%). Is this not too much? Should I put only 6 (1980 µF)?

I followed the C2 C8 discussion, I stick to the plan so, yep? There is no need to avoid or change these, maybe polypropylene 0.1µF in place of C2?

what's the name of the tiny bits that are pushed in the heatsink taping holes of the STEPS, that are used to be soldered on the pcb to fix the heatsink, and can I find these alone?

I read again the initial setup, is it not dangerous to lead-test R9 being so close to the heatsinks (V+ right?) What if a short between V+ and R9 either before or after?

Should I use multistranded wires for voltage and mains?

And how do you heatshrink the heatshrink? I always end burning it.

AMB, Close to the C8 close to the D1, there are two holes not used, one could take V+ and ground from there?

What is the best way to clean the solder iron tip, the humid foam - sponge, to sand it a little bit before heating it, a kind of white stone similar to Alun or something like that?

Thanks for all,

GregVDS

 

[Jazper]

Quote:

Originally Posted by GregVDS I followed the C2 C8 discussion, I stick to the plan so, yep? There is no need to avoid or change these, maybe polypropylene 0.1µF in place of C2?

if you followed my tip earlier, the capacitors you ordered for c8 and c2 will be 0.1uF polypropylene so you have nothing to worry about there

 

[amb]

Quote:

Originally Posted by GregVDS I realized I ordered 9 x 330µF nichicon UHE for M³ C7, hence I can have as much as 2970 µF (I know, +- 10%). Is this not too much? Should I put only 6 (1980 µF)?

9 x 330µF is fine.

Quote:

I followed the C2 C8 discussion, I stick to the plan so, yep? There is no need to avoid or change these, maybe polypropylene 0.1µF in place of C2?

1µF MKT or MKS will work fine, so will 0.1µF MKP.

Quote:

what's the name of the tiny bits that are pushed in the heatsink taping holes of the STEPS, that are used to be soldered on the pcb to fix the heatsink, and can I find these alone?

Those are pins. The heatsink that tangent specifies for the STEPS come with them pressed in, and you solder the heatsink to the board. For the M³, I supply heatsinks without pins. I suggest using M3 screws (either self-tapping or machine screws. If you use machine screws then you need to tap the heatsinks). Screws rather than solder makes the heatsinks easier to remove if you ever need to do so.

Quote:

I read again the initial setup, is it not dangerous to lead-test R9 being so close to the heatsinks (V+ right?) What if a short between V+ and R9 either before or after?

Just be very careful with your test probes when you do this.

Quote:

Should I use multistranded wires for voltage and mains?

I do, but it's up to you what you want to do. Just make sure to insulate all connections, leave no exposed high voltage AC mains anywhere. Use plastic-shrouded push-on lugs for the IEC AC module and power switch wiring (and/or heat-shrink tubing). Make sure everything is physically secure.

Quote:

And how do you heatshrink the heatshrink? I always end burning it.

There are special heat guns for this purpose. They look like hair dryers but produce a more focused flow of hot air. Some have a temperature adjustment switch.

Quote:

AMB, Close to the C8 close to the D1, there are two holes not used, one could take V+ and ground from there?

Those are large vias to connect traces between the top and bottom pcb layers. They are actually the V+ and V- lines, not ground.

Quote:

What is the best way to clean the solder iron tip, the humid foam - sponge, to sand it a little bit before heating it, a kind of white stone similar to Alun or something like that?

Don't sand your soldering iron tip if it's good quality. You'll ruin it. Just clean by wiping on a damp sponge when it's hot.

 

[GregVDS]

Thanks,

I finished the STEPS yestereve. All is working fine. I hope to begin the M³ this evening. The most annoying part was the soldering of the heatsink 'legs'. Heatsink actually sinks you guess what? Heat, so it's almost all the time not hot enough for correct soldering. I had also a hard time putting the common choke filter. I went for the big one (in tangentsoft website list), and with the Mouser C1/C3 just close, legs where not perfectly aligned, but pushing a little bit did it, though the choke is not perfectly levelled to pcb.

Is there an order to assemble the pcb? I mean, more detailed than from low profile to high profiles? I think mainly of access problem to holes while soldering. Some components are to be placed first to avoid their legs be behind other already soldered very close? I don't know if I'm very clear here, sorry for that.

I already tap the 6 heatsinks with a self-tapping screw 4-94 or something like that. I think this is safer to do that before assembly, in order to avoid ruining the almost finished M³ with a very long and hard screwdriver slip, SKKRATCH, oups .

I promise you I will try to post pictures, but I still don't understand how people here put in their message directly seeable pictures wider than 1000 pixels.

All the best,

GregVDS

ps Jazper: don't be angry for I stick to AMB specs, I think the best way to begin is to do the normal layout, listen to it long enough to know its characteristics, then go for modding, and compare and evaluate changes. If I straight go for 0.1µF, How can I say if it's better, or even worth it? Anyway thanks for advices and comments!

 

[amb]

Quote:

Originally Posted by GregVDS The most annoying part was the soldering of the heatsink 'legs'. Heatsink actually sinks you guess what? Heat, so it's almost all the time not hot enough for correct soldering.

I don't know what kind of soldering iron you have, but this is a good reason why a adjustable-temperature soldering station is a good idea. For fine PCB work you could use just enough heat to do the job without damaging the part of the board, while soldering big items like that you could crank up the heat.

Quote:

Is there an order to assemble the pcb? I mean, more detailed than from low profile to high profiles? I think mainly of access problem to holes while soldering. Some components are to be placed first to avoid their legs be behind other already soldered very close? I don't know if I'm very clear here, sorry for that.

Basically, the lowest profile parts go on first, then work your way up. Sometimes it helps to have a piece of foam or something that you could put over the part to keep it fully seated while you solder the part in with the board upside-down. If the part has more than two pins, you could lightly tack-solder just two opposing pins to "seat" the part all the way in, and then do the formal soldering of all the pins.

Quote:

I still don't understand how people here put in their message directly seeable pictures wider than 1000 pixels.

Don't post any images that wide, because it won't fit in the window completely on many people's computer screens. Shrink it down to 800 pixels or smaller.

 

[GregVDS]

Ok,

just to let you know, I nearly finished the amp. The STEPS is finished and works fine. I just have C4 and C5 to solder (and the crossfeed, but this can be done after initial setup).

I nearly died yesterday evening. I just had finished to solder the C7 and assembled and soldered the 6 mosfet. I smoke a pipe in the garden, simply happy (poor unknowing guy), when I suddenly remember the mosfets are not identical!! I had 3 time half the chance the 34N and the 24N being in the right places: Ground channel, ok, left channel, ok, could it be I have chance, right? Wrong!! I had to desolder (silver solder) the two right mosfet to exchange them. Now I will never let you see the bottom of the pcb! I was sad about that, for I knew it, I should have taken all the papers and reread them again, even to solder C7, or mosfet pairs. I only hope now I made it right, and everything is just fine. I hope tonight to put C4 and C5 in place, and make the initial setup.

AMB, if I burned a mosfet, how will the amp react, or how can I check they are ok now?

Many thanks, apart from this, everything just went fine.

All the best,

GregVDS

 

[amb]

Quote:

Originally Posted by GregVDS I smoke a pipe in the garden, simply happy (poor unknowing guy), when I suddenly remember the mosfets are not identical!!

You aren't the first to make this mistake.

At least you remembered and understood that there was the problem before you applied power... (or so your description seems to indicate)

Quote:

AMB, if I burned a mosfet, how will the amp react, or how can I check they are ok now?

If you never powered the amp on and fixed the mistake, then it's probably fine. Actually, the MOSFETs have internal reverse diodes between the drain and source pins, so if you had the wrong devices installed it will appear shorted across the power rails and cause your power supply to shut down. If any MOSFET is damaged then you won't be able to get a good DC offset measurement during initial setup.

 

[GregVDS]

No power applied, since C4 and C5 are still absent. And even at that point, now I know I will double-check everything, after having removed the rosin with isopropanol and teethbrush!

Can I majke the initial setup without the output jack soldered, nor the rca connectors, nor the crossfeed at the input? I mean, Can I make the setup with just the led and voltage supply evidently)?

I had also a question about the setup. Steps have to be done repeatedly for ground, left and right. For left, can I let the ground opamp in place, or should I remove it, and again, for the right, can I let ground and left in place, or should I again remove the others?

Thanks again.

GregVDS

 

[amb]

Quote:

Originally Posted by GregVDS Can I majke the initial setup without the output jack soldered, nor the rca connectors, nor the crossfeed at the input? I mean, Can I make the setup with just the led and voltage supply evidently)?

Yes.

Quote:

I had also a question about the setup. Steps have to be done repeatedly for ground, left and right. For left, can I let the ground opamp in place, or should I remove it, and again, for the right, can I let ground and left in place, or should I again remove the others?

Once you've completed setup of a channel, you don't need to remove the opamp for that channel.

 

[rreynol]

Just about done with my M3 amp.

All thats left to do is trim the pot shafts. I would have liked more lighting of the interior but I didnt feel like adding a 3rd or 4th LED. The two that are in there are 8000 mCD 3.5V 5mm's running with aboutr 13mA through each (they are rated up to 30mA). Its enough to let me know that the amp is powered on so they serve their purpose. I'll be putting together a matching STEPS in a 1455N16 but I think I'm gonna take a break from DIY-ing for a while.

P.S. pic quality isnt the best. My digital camera is old.

 

[Jazper]

Quote:

Originally Posted by rreynol Just about done with my M3 amp. All thats left to do is trim the pot shafts. I would have liked more lighting of the interior but I didnt feel like adding a 3rd or 4th LED. The two that are in there are 8000 mCD 3.5V 5mm's running with aboutr 13mA through each (they are rated up to 30mA). Its enough to let me know that the amp is powered on so they serve their purpose. I'll be putting together a matching STEPS in a 1455N16 but I think I'm gonna take a break from DIY-ing for a while. P.S. pic quality isnt the best. My digital camera is old.

Looks good, what do you think of how it sounds?

 

[Vladco]

Rreynol which case you are using? Is it standard hammond case?
Vlad

 

[amb]

Quote:

Originally Posted by Vladco Rreynol which case you are using? Is it standard hammond case? Vlad

Looks like a Hammond 1455T2202. The 1455T2201 will also work.

 

[rreynol]

Quote:

Originally Posted by Jazper Looks good, what do you think of how it sounds?

My good cans (DT770) are at work. Won't get to try those out til tomorrow. I'm sure my portapros don't do the m3 justice but it sounds excellent.



Amb is correct. Its the Hammond 1455T2202 (Mouser now stocks the larger sizes of Hammond cases)

 

[phobus]

I was re-wiring my M3, and put everything back together, but now...

With the Ground opamp out, the voltages measure fine. Once I put the opamp in, the voltage between pins 4 and 7 read 6.5 volts, and the power supply gets REALLY hot (its not the opamp, I tried other ones).... This doesn't happen with the L/R opamps so I'm guessing I blew something out in the ground channel. Is there anything to check for, or should I start replacing components?

Thanks