the Poor Man 660 support thread

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OK, I tried power up. No tubes installed. Voltages looked ok, bridge rectifier got HOT, then transformer started to smell and get very warm. Bam! fuse blew. Now I have no resistance between the primary and secondaries. Blown transformer?
I am using the Edcor these are my connections:

Primary: blk/grn blk-white/ grn-white

15 volt -centertap-15 volt from transformer connected to AC in on board.
250 AC from transformer connected to 250 in on board
9 volt AC from transformer connected to AC in on bridge rectifier
DC out of rectifier connected to "from rectifier" on board
1 ohm 50 watt resistor connected off board fastened to chassis.

I don't see any blatant mistakes but there must be one!
Help!

David
 
0 ohms 'tween primary and secondary?
thats not good.
try disconnecting all power trans leads and 'ohm them out' --that is, determine what the heads and tails (and center tap) of each winding is. and if the leads are'nt just colored wrong.
 
Disconnected transformer, this is what I got...

Primary to 15volt leg 1.5 ohm
primary to 15 volt centertap 1.5ohm
primary to 2nd 15 volt leg 1.5 0hm
primary to 250 leg infinity
primary to 2nd 250 leg infinity
primary to 9 volt leg 1 ohm
primary to 2nd 9 volt leg 1 ohm

hope this sheds some light.....
 
[quote author="CJ"]Has anybody tried Schotky diodes to rectify the DC control voltage?

We were talkin this up at AES with the Fairchild guy.
He might be using them in the new 670, I forgot.

The original diodes were a pain to source.
In fact, that is one of the few parts that I know nothing about.
I asked Rein about them, but he could not remember.
Diodes were changing quickly back then, there were many more choices by the time the 670 came out, as opposed to the 660.
Germanium?
I do not know.
Nothing on any of the schematics I have seen.
Maybe Alexandervich might know.[/quote]
Thanks Volker for designing the diode part of pcb like this :idea: You did perfect job for dropping DIL Socket 8-Pin :grin: So, I prepared for the possible change or experimenting. Of course first set of diodes are 1n4148 as stated but I will try some Shotky's or whatever later... :green:
pm660-diodes.jpg
 
[quote author="Moby"]You did perfect job for dropping DIL Socket 8-Pin :grin: So, I prepared for the possible change or experimenting. Of course first set of diodes are 1n4148 as stated but I will try some Shotky's or whatever later... :green: [/quote]
:cool: cool - a Fairchild with Plug-Ins :green:
 
[quote author="[silent:arts]"][quote author="Moby"]You did perfect job for dropping DIL Socket 8-Pin :grin: So, I prepared for the possible change or experimenting. Of course first set of diodes are 1n4148 as stated but I will try some Shotky's or whatever later... :green: [/quote]
:cool: cool - a Fairchild with Plug-Ins :green:[/quote]
Plug'n play ;-) yes, I will continiue that under http://www.groupdiy.com/index.php?topic=28274&start=666 Now it's time to finish the beast :cool:
 
[quote author="CJ"]Cool idea on the socket.[/quote]
Thanks mate :green: Now , give some idea about possible diodes to experiment with.... :cool:
 
[quote author="Moby"][quote author="CJ"]Cool idea on the socket.[/quote]
Thanks mate :green: Now , give some idea about possible diodes to experiment with.... :cool:[/quote]

Possibly try "Geranium" :razz: diodes - is it OA81 OA91?
What about diodes used in other compessor bridge ccts like the neve stuff - I think they were something like BAT42 or BAW62 - something like that - check on the 33609 build thread :thumb:
 
thanks, just keep comming with ideas, right after I finish my units I will start with experimenting and I will do the samples for every diode competitor. So, we are be able to judge together about :)
 
[quote author="elektrovolt"]what would be the effect of placing different diodes ?[/quote]
I'm not sure about but I'm curious. I doubt that it will be any difference but ears can say something else. 1n4148 are pretty fast and maybe some slower (older) ones can do the difference....
 
Hi Folks,

finally i´m ready. Tata :grin:
My PSU Trafo have to go outside the box. With open case i have no hum.
With closed case i have hum @ 88db fs. Strange isn´t it :?:
But i can live with such s/n ratio.
Muchos Gracias, to Volker, Analag and Bernd for such a great project...
I love you all....Lars
fstotal.jpg

fslinks.jpg

fsrechts.jpg

fsrohre.jpg

fsrorhre2.jpg

fsinnen.jpg

fs.jpg
 
Lars,

KILLER! :thumb:

What resistor Value did you end up with for the Heaters/Filaments ?
...using what Power Transformer?

Also... how does it sound... do you like it?

Just curious to here how different guys like the unit... there's not too many built yet so feedback is cool.

I Haven't laid out my front panel & love yours... looks like bernbrue's.
 
What resistor Value did you end up with for the Heaters/Filaments ?
0,5R for 6 volts, on monday i will try 0,47r....psu is from rondo.

Also... how does it sound... do you like it?
I only did a quick test, i can tell more later. I do not know if i like it.
it sounds diffrerent, then my other compressors.

I Haven't laid out my front panel & love yours... looks like bernbrue's.
Its Bernds. :wink:
 
:shock: :shock: :shock: :shock: :shock:
Lars, fast as always :wink:
great work :thumb:
I'm sure you will like it.
but I think you need some more rackspace ...
too much successful DIY :green:
 
Lars, it's looking amazing. Congratulations :guinness: Please do some listening tests and tell us about sound... As always, it will be great to hear some clips :wink:
 
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