dspruill

the Poor Man 660 support thread
« Reply #660 on: October 19, 2008, 03:51:04 PM »
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


shabtek

wow
« Reply #661 on: October 19, 2008, 04:21:05 PM »
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.
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

dspruill

the Poor Man 660 support thread
« Reply #662 on: October 19, 2008, 05:48:40 PM »
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.....

Moby

the Poor Man 660 support thread
« Reply #663 on: October 20, 2008, 07:06:24 AM »
Quote from: "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.

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:
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

dspruill

the Poor Man 660 support thread
« Reply #664 on: October 20, 2008, 09:03:50 AM »
Found my screw up. Bridge rectifier was connected incorrectly. I'll be calling Edcor today!

Its only money......

David

[silent:arts]

the Poor Man 660 support thread
« Reply #665 on: October 20, 2008, 11:02:17 AM »
Quote from: "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:

 :cool: cool - a Fairchild with Plug-Ins :green:

Moby

the Poor Man 660 support thread
« Reply #666 on: October 20, 2008, 11:45:58 AM »
Quote from: "[silent:arts
"]
Quote from: "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:

 :cool: cool - a Fairchild with Plug-Ins :green:

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:
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

CJ

the Poor Man 660 support thread
« Reply #667 on: October 21, 2008, 05:51:41 AM »
Cool idea on the socket.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Moby

the Poor Man 660 support thread
« Reply #668 on: October 21, 2008, 08:50:40 AM »
Quote from: "CJ"
Cool idea on the socket.

Thanks mate :green: Now , give some idea about possible diodes to experiment with....  :cool:
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

mikeyB

the Poor Man 660 support thread
« Reply #669 on: October 22, 2008, 10:22:43 AM »
Quote from: "Moby"
Quote from: "CJ"
Cool idea on the socket.

Thanks mate :green: Now , give some idea about possible diodes to experiment with....  :cool:


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:
making better music!


Moby

the Poor Man 660 support thread
« Reply #670 on: October 22, 2008, 01:09:23 PM »
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 :)
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

elektrovolt

the Poor Man 660 support thread
« Reply #671 on: October 22, 2008, 06:39:46 PM »
what would be the effect of placing different diodes ?

Moby

the Poor Man 660 support thread
« Reply #672 on: October 22, 2008, 07:21:25 PM »
Quote from: "elektrovolt"
what would be the effect of placing different diodes ?

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....
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

waldorfcave

the Poor Man 660 support thread
« Reply #673 on: November 01, 2008, 01:13:20 PM »
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







khstudio

the Poor Man 660 support thread
« Reply #674 on: November 01, 2008, 01:44:12 PM »
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.
Kevin ~ KHStudio

waldorfcave

the Poor Man 660 support thread
« Reply #675 on: November 01, 2008, 02:02:48 PM »
Quote
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.

Quote
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.

Quote
I Haven't laid out my front panel & love yours... looks like bernbrue's.

Its Bernds. :wink:

[silent:arts]

the Poor Man 660 support thread
« Reply #676 on: November 01, 2008, 03:44:52 PM »
: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:

Moby

the Poor Man 660 support thread
« Reply #677 on: November 01, 2008, 04:09:29 PM »
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:
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

Benny

the Poor Man 660 support thread
« Reply #678 on: November 02, 2008, 03:31:23 AM »
Wow, nice one Lars. :thumb:
I hope I'll find a few days off to work on my Pm670...

RedNoise

the Poor Man 660 support thread
« Reply #679 on: November 02, 2008, 05:05:32 AM »
:thumb:
If your neighbour is hunger : don't give him fish , teach him how to fish ...
if you don't like it don't buy it ;-)  [Wolker Texas Ranger] ( ;-) )


 

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