the Poor Man 660 support thread

[skal1]

any one know where i can buy the 1/2 watt resistor for psu and audio stage this diy , i have checked a number of suppliers , but they only do one or two values needed for this project.

Bless up

skal1

 

[veermaster]

What do you think of these:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=130241150982&ssPageName=STRK:MEWA:IT&ih=003

He does have 10Ks, maybe he is willing to do custom 15Ks if enough people are interested?
emre

 

[kazper]

Not sure if the 1/4 W resistors on the switches will cause you problems with this build and if it's MBB or BBM type of switching.

Otherwise it looks great.

 

[veermaster]

Hm, just saw that these are "linear ladder style" but we need log right?
Maybe these ones:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=300245229284&ssPageName=STRK:MEWA:IT&ih=020

One would have to ask the seller what kind these are... (well, I will)

 

[rrs]

About to make mouser order but have one question.
I am ordering the Omron G5v-2 relay it's 12V yeh.
There are 3 I can choose from (Solder pin or PCB Terminal)+ (High sensitivity or Non Latching)
what do I go for??

 

[schmidlin]

Hi All,
I recently discovered this post and have read most of the 14 pages. Very impressive. I hope you all take some time to reflect on how much of a blessing this internet thing is. I remember the days when Hamvention or a local guru was the only source for good parts/advice.
First, I am impressed with how affordable the Edcor transformers are, yet surprised at how many folks chimed in to buy some. I could never find them using regular search techniques, so I wonder about their quality. Does anyone have any experience with these? If they are good, I'm down for plenty.
Also, do any of you plan on nixing the 6386 for a less expen$ive 6BA6 or 6BJ6? Or? If so, how are you implementing them?
Thanks gang, keep up the great work,
-Schmidlin

 

[3phase]

Yep..i also discoverd the thread...
impressive projekt...

I havent found the schematics of the thing yet... is this only via the pcb´s?

and are there any ready yet? how is the result?

 

[cannikin]

you guys really reading the thread? it doesn't use 6386 tubes.... and the schematics .... well.... do some searching in the should I? thread and all will be revealed to you.

 

[3phase]

should I? yep..i ve read the thread..but i ve overseen any links to the schematics...

 

[cannikin]

[quote author="3phase"]should I? yep..i ve read the thread..but i ve overseen any links to the schematics...[/quote]

OK read this one:

http://www.groupdiy.com/index.php?topic=28586&highlight=pm660

 

[schmidlin]

I feel a little crunchy, like I am butting into a conversation and asking dumb questions, so my apologies and please bear with me.
I think I get what is going on now. I read the parts list
I don't plan to tackle this project, but am dying to hear the results: looks like you are firing on all cylinders as a team.
But I still would like any feedback on the Edcor's. For those prices, I suppose I should just try some, but am still curious.
Thanks All.

 

[Rob Flinn]

Schmidlin

If you do some searches about Edcors you will find that they are quite well thought of round here, particularly by Analag who designed this project & also the DOAC.

Like I said with some searching you should find sevral opinions.

 

[tommypiper]

[quote author="[silent:arts]"]HEATER PSU

the Heater PSU is a rectified, unregulated one.
the bridge rectifier should be a 12A or more, mounted off board to the chassis. they look like this:
...
we want to be as near as possible to 6.3V, this is done by the value of R15.
again: this resistor is mounted off board and gets very hot. a 50W resistor is a good idea, something like this:
...
one problem we have with the "right" value of R15:
- mains voltage will vary
- the secondary of each transformer will vary
- the consumption of each tube will vary

best thing is to have a few values handy to test it.[/quote]

With all those issues... Wouldn't it be easier to use a regulator?

 

[emrr]

[quote author="tommypiper"][quote author="[silent:arts]"]HEATER PSU

the Heater PSU is a rectified, unregulated one.
the bridge rectifier should be a 12A or more, mounted off board to the chassis. they look like this:
...
we want to be as near as possible to 6.3V, this is done by the value of R15.
again: this resistor is mounted off board and gets very hot. a 50W resistor is a good idea, something like this:
...
one problem we have with the "right" value of R15:
- mains voltage will vary
- the secondary of each transformer will vary
- the consumption of each tube will vary

best thing is to have a few values handy to test it.[/quote]

With all those issues... Wouldn't it be easier to use a regulator?[/quote]

No. The only issue is that no one has figured out the 2 possible values and ratings (mono or stereo) for each possible power transformer. We have, what, 3 different group buy transformers in play, and the value/rating may vary slightly between them. Someone will undoubtably experiment and find good values, and hopefully post them. Otherwise we buy a selection, find the right one, and save the rest for something else.

Mains AC and tube current consumption variation aren't real issues. Secondary AC and current RELATIVE to tube draw will be.

 

[Nele]

[quote author="tommypiper"]With all those issues... Wouldn't it be easier to use a regulator?[/quote]

my thoughts as well. Why not use a 317 with a TIP2955 for instance...

 

[[silent:arts]]

emrr is right.

until know my heater tests are done with an extra 9V/6A transformer.
since I haven't received my final PSU transformer either (bernbrue group buy), and won't get the models from codered, Kid Squid or Edcor I can't give you the exact values.

the value is around 1R for stereo, 2R for mono.

remember, for stereo we need nearly 6A for the heaters, and a 6A regulated PSU would be a little bit oversized in my opinion.
anyway, it is what analag did in his unit, so why change it.

 

[Moby]

Analag & Valker, how complicated will be to add makeup gain for PM? Valker did you received my email?

 

[[silent:arts]]

Moby, 18dB gain should be enough for a Compressor.
btw, your PCBs and schematic are shipped.

 

[Moby]

Cool, then I will wait to see schemo... thanks ;-)

 

[emrr]

[quote author="Nele"][quote author="tommypiper"]With all those issues... Wouldn't it be easier to use a regulator?[/quote]

my thoughts as well. Why not use a 317 with a TIP2955 for instance...[/quote]

You want to regulate a lightbulb? :razz: Keep it simple.....