the Poor Man 660 support thread

[Kingston]

Anybody find a suitable output transformer replacement yet? One that does not break the bank he he....

LL1676 is great. Breaks bank, yes. Very little modern transformers out there suited for this task with enough headroom AND center tap for primary.

 

[radiance]

Ah, I see. I was confused since rrs said he will use the LL1676 on the input.
The LL1676 can be used both ways I guess.
I'm planning to use the Haufe T5223 (reversed) on the input.
Not sure it will work. Maybe some of you can look into the data sheet attached. These Haufe data sheets are confusing somehow.


EDIT: reading to this thread again  I saw I've asked about using the T5223 earlier in this thread. My build is taking so long that I forgot about that...

 

[analag]

That's why I chose the Edcor for this design...cheap yet good.

 

[horvitz]

It's worth mentioning that Edcor have packages "PT-660" and "PT-670" which are everything you need for this project, discounted 20% over their already good prices.  Don't think I've seen that mentioned here on the thread.  The nice girl there who took my order was kind enough to tell me when she realized what I was working on.  $128 for all 9 pieces is pretty good!

  Brian

 

[kazper]

Silent:arts, are there sockets that fit these boards without modification?

sure - they are called "miniature 9pin tube sockets" and look like this:

however, don't ask me for an US based source, and they really should be ceramic and not plastic.
since a lot of these sockets have been bought for this projects someone should be able to provide a US part number and supplier ...

Ebay or Cascadesurplus.com

 

[mitsos]

thanks kazper. I already rigged mine up another with resistor leads like I said before, but I'm gonna pick some up for the future.

I got mine wired up, but have some issues. At first I had no sound (and no purrty heater glow) then, after it had been on for a few minutes I got some kinda crappy distorted sound out of it. The sidechain attenuator(threshold?) control didnt do anything, but the 5687's didn't even remotely light up (the 6bc8s were just slightly lit) and the input atten and attack kinda had some effect. Two things, PSU related, and maybe one not PSU related.

My heaters are only 3V! So there's the obvious problem. The trafo I am using is only 6VAC or so, (I'm getting 8.7VDC with no load after rectification) so I'm gonna pull out the 2R 50W resistor 1R, 15W wirewound resistor like the ones in crossovers (My ideal number is 0.92R but I haven't found on yet).  If my quickie calculations are correct it should be enough to take the heater down to 6.1V while dissipating about 6W.

The other thing is that the 245V and 136V, which were just fine a minute ago (since then I powered down, bled caps, and powered up but forgot to remove my bleeder resistor (47K I think) from my DMM (I had them connected together so I could watch the voltage dropping)  so when I went to measure voltages with the unit on again, I measured with the bleeder resistor in parallel to my DMM. I'm not sure if this might have blown up the second IRF (I hope not) but I am now getting less than 13V instead of 245 and 4 instead of 136. I'm guessing Q5 is done, because I'm getting 13V on the cathode side of D9 (protection diode for Q5?) and 4V on the anode side.

I used two IRF820 on this PSU (I got them when the boards were first offered) so maybe that's the problem? Anyway, that's going to take me at least a month to get, so that sucks, but I guess I'll pick up 2 840s.  Anyway, it's going to take that long to get the case done, but I did want to hear this thing working.

the third problem I won't know if it's actually a problem until I get the supply working but I used an OLD mallory 500 Ohm T-pad attenuator on the input and I'm not sure what state it's in. I thought I tested it ages ago, but who knows anymore.

Volker, do you have the exact dimensions of the holes on the PCBs? I'd like to get my case with holes pre-punched/threaded and would rather not measure myself so it will be more exact (I was a bit off on my GSSL case : ).

So that's it for me for now..

cheers!

 

[loopermc5]

thanks kazper. I already rigged mine up another with resistor leads like I said before, but I'm gonna pick some up for the future.

I got mine wired up, but have some issues. At first I had no sound (and no purrty heater glow) then, after it had been on for a few minutes I got some kinda crappy distorted sound out of it. The sidechain attenuator(threshold?) control didnt do anything, but the 5687's didn't even remotely light up (the 6bc8s were just slightly lit) and the input atten and attack kinda had some effect. Two things, PSU related, and maybe one not PSU related.

My heaters are only 3V! So there's the obvious problem. The trafo I am using is only 6VAC or so, (I'm getting 8.7VDC with no load after rectification) so I'm gonna pull out the 2R 50W resistor 1R, 15W wirewound resistor like the ones in crossovers (My ideal number is 0.92R but I haven't found on yet).  If my quickie calculations are correct it should be enough to take the heater down to 6.1V while dissipating about 6W.

The other thing is that the 245V and 136V, which were just fine a minute ago (since then I powered down, bled caps, and powered up but forgot to remove my bleeder resistor (47K I think) from my DMM (I had them connected together so I could watch the voltage dropping)  so when I went to measure voltages with the unit on again, I measured with the bleeder resistor in parallel to my DMM. I'm not sure if this might have blown up the second IRF (I hope not) but I am now getting less than 13V instead of 245 and 4 instead of 136. I'm guessing Q5 is done, because I'm getting 13V on the cathode side of D9 (protection diode for Q5?) and 4V on the anode side.

I used two IRF820 on this PSU (I got them when the boards were first offered) so maybe that's the problem? Anyway, that's going to take me at least a month to get, so that sucks, but I guess I'll pick up 2 840s.  Anyway, it's going to take that long to get the case done, but I did want to hear this thing working.

the third problem I won't know if it's actually a problem until I get the supply working but I used an OLD mallory 500 Ohm T-pad attenuator on the input and I'm not sure what state it's in. I thought I tested it ages ago, but who knows anymore.

Volker, do you have the exact dimensions of the holes on the PCBs? I'd like to get my case with holes pre-punched/threaded and would rather not measure myself so it will be more exact (I was a bit off on my GSSL case : ).

So that's it for me for now..

cheers!

I have 2 extra IRF840 if you need them I can put them in the post pm me.

 

[mitsos]

Thanks for the offer man, I appreciate it! But I'm gonna be traveling quite a bit this month so I don't realistically foresee getting to this before I get my IRFs. Plus I need to get the new high watt / low R resistor for the heater, so it's gonna be a little while.  But thanks, really. very cool.

cheers!

 

[kazper]

Volker, do you have the exact dimensions of the holes on the PCBs? I'd like to get my case with holes pre-punched/threaded and would rather not measure myself so it will be more exact (I was a bit off on my GSSL case : ).

I really should do a metal work meta.....

Figure out about where you want to place the pcb and place it on the case. I use a L shaped square and align it so that it's straight to the metal work edge. I sometimes use other small pcb's to help space the pcb i'm trying to secure out when marking. There is a couple ways to make sure you holes align up..

A) Use a center punch that fits the pcb hole and place a starting punch in the metal in all the holes.
B) Drill one hole and then fasten the pcb snug but loosely to the case and with out a standoff. Align up the other holes, then drill.
c) Use a sharp pencil, mark and then carefully use a hand punch and set your starter holes.

Always check before you drill and use a flash light to verify the mark through the pcb mounting holes. You may need to use a spring loaded centering tool and repeat the punch to correct an off marked hole. In starting the drill, place a stopped bit in the hole. If making a large hole start with a small bit to center the larger hole.

A couple tips, use small screws I use 4-40, you can drill the holes oversized (1/8") so you have a little play. I prefer to tap my cases holes and thread in the bottom screws. Even if there slightly off, tightening them up fully will cause them to straighten out in the thin sheet metal.


I typically don't measure much when laying stuff out like this past making sure the board is square to the sheet metal. Iv'e done far to much layout work so It's more of a bother unless you don't have something in stock yet. I tend to wait till it's in my hands before I spend the effort.

 

[mitsos]

as my 3 year old likes to say. "Aaaaaaah  NO!" 

I know this is DIY, but I've started preferring doing it myself in CAD and having a machine punch the holes ;D

It's just that metalwork takes me soooo long and it's cheap to put some PEM fasteners in a case, when I have to get them custom anyway (no parmetal in my neck of the woods).

that said, someone should do a metal work meta.

 

[[silent:arts]]

from the first post of this thread

PM660 Component Placement and Dimensions
PSU660 Component Placement and Dimensions

hole diameters are 3,1mm

 

[TheGuitarist]

Hey guys, just wondering if you can help me trace down what i think is a short. The power transformer is audibly buzzing a little bit, not as bad as a direct short, but buzzing quietly with that same sound.

The compressor IS passing signal, but its very quiet and distorted, i have to max out the gain on the compressor to hear it.

Any thoughts on where this would be happening? I had a look at all the solder joints and couldnt see any shorts. Any specific points i should be checking voltages at?

If it helps i have the slow start heater and time constraint mod boards. Even with flicking all the switches it doesn't help.

Any help would be much appreciated.

 

[crisotop]

Would check all the psu voltages first without attaching the audio board. If you get correct voltages at the psu, then connect one audio board at a time. Is the psu trafo buzzing even with just the psu board connected?

good luck!
Christoph

 

[TheGuitarist]

Ok going through the voltages, found the problem pretty quickly, even removed off the audio board.

Its the 245v, any thoughts on where to probe next? I still can't see any shorts, but not sure what to check next. Also getting some weird voltage readings off my toroid. i'm getting 8.17v off one of my secondaries instead of 15v. But even with all those disconnected, its still buzzing faintly.

 

[crisotop]

is it a rondo-müller torroid from a groupbuy? does it have 115+115 primaries? Are they wired correctly?

hth, christoph

 

[TheGuitarist]

Not sure, i got it from another forum member, the voltage are written down on some masking tape on the side.

Red and black wires for 115v primaries. Should be wired correctly, middle red and black wires are connected to put it in series.

I just checked now, the wires that are supposed to carry 250v are only carrying 140. I'll attatch a picture of how i've wired the primaries.

Its strange, i could have sworn i checked all these voltages last time i was working on this... Always the most basic things i suppose.

http://img704.imageshack.us/f/image1qlu.jpg/

 

[crisotop]

Did you measure the secondary voltages with nothing connected to them? Otherwise it could be a short/error on the psu board.

christoph

 

[TheGuitarist]

Ok disconnected all the secondaries, and its a bit odd. the transformer is STILL buzzing.

The grey 250v cables read 275 unloaded when testing both cables, but around 130 when one is referenced to ground.

Now i didn't this transformers were supposed to audibly buzz... but it isn't connected to anything else.

 

[crisotop]

What are your readings on the other secondary windings? But buzzing sounds without any load is not a good sign - I guess you don't have a replacement for comparisons?

 

[TheGuitarist]

No i don't unfortunately, All the voltages are close enough, 17v for the 15v and 10v for the 9v.


It couldn't be that i've gotten the AC wires around the wrong way? Like blue instead of brown etc. I didn't think it could make a difference. Could it be insufficient insulation anywhere? I do have that shielding strip wrapped around it.