the Poor Man 660 support thread

[emrr]

no output control on the original. Just input as here.

 

[Osse]

Then my question is:

Is there any benefit from doing this kind of design? 2x gain reductors and no make up? Seems very stupid if you ask me, but who am I to criticise the most attractive compressor around.

Could anyone give me some reasons to do a design like this?

Isn't the most effective way to have a fixed treshold, an input, and an output?

Thanks!

 

[khstudio]

HEATSINKS - MOUSER

Q4, Q5
Mouser Part #: 532-529902B25G
Manufacturer Part #: 529902B02500G
Manufacturer: Aavid Thermalloy
Description: Heatsink TO-220, VERT 3.5 TR
Case Type: TO-220
Dimensions: 41.91 mm L x 25.4 mm W x 50.8 mm H

IC1, IC2
Mouser Part #: 532-531102B25G
Manufacturer Part #: 531102B02500G
Manufacturer: Aavid Thermalloy
Description: Heatsink TO-220, VERT 10.4 TR
Case Type: TO-220
Dimensions: 12.7 mm L x 35.052 mm W x 38.1 mm H

 

[emrr]

[quote author="Osse"]
Is there any benefit from doing this kind of design? 2x gain reductors and no make up? Seems very stupid if you ask me, but who am I to criticise the most attractive compressor around.

Could anyone give me some reasons to do a design like this?

Isn't the most effective way to have a fixed treshold, an input, and an output?
[/quote]

Grouchy old curmudgeon checking in....:green:

You are right, you don't understand. The unit has gain; that's the same as make-up gain. 18 dB with max input setting and no limiting. Unity gain throughput at max input setting IF you are doing 18 dB of limiting. I'm not sure how you keep thinking there's no gain to play with; there is almost no such thing as a unity gain tube amp. There are several threads about threshold in tube limiters you should find; they will give you every reason. This thread is long enough already. Suffice to say if you want the ratio to be unchanged, you leave the threshold fixed and drive it more or less to achieve 'variable threshold'. The side chain has it's own gain knob called threshold. There are limiters with movable threshold and unity gain; this isn't one of them. Same outcome; all discussion is semantics. It's all there in the block diagram.

 

[khstudio]

Could I get an estimated value for R15
the "Off board 25/50W resistor" for the heaters

using the EDCORE Power Trans:

GROUP BUY - XPWR063
Dual 115V 50/60Hz to 250 200mA,
9 volt 6A, 15 volt center tapped 1A
15 volt center tapped 1A

I'm in the US & my wall voltage is pretty steady
Approximately = 120v AC 60Hz

 

[emrr]

[quote author="[silent:arts]"]
the value is around 1R for stereo, 2R for mono.
[/quote]

 

[flintan]

I believe there is no way to hook up this Poorchild for M/S encoding/decoding if using the Edcors that doesn't have dual windings?

 

[emrr]

[quote author="flintan"]I believe there is no way to hook up this Poorchild for M/S encoding/decoding if using the Edcors that doesn't have dual windings?[/quote]

nope. Have to use different transformers if you want that. On second thought, you could if you're willing to hack the transformers. It's not hard to separate the center tap connections. You'll just have to figure out what to do with the loose wire.

 

[flintan]

Ok, thanks! Is the two windings just soldered to the centertap lug? Then it would be quite easy. :grin:

But on second thought, i wonder if the Edcor windings are close enough matched for this type of application..

 

[mitsos]

[quote author="khstudio"]Could I get an estimated value for R15
the "Off board 25/50W resistor" for the heaters
[/quote]I too am wondering what to get, but I did not get a group buy power trafo because I thought it was a waste of $$ for only one channel (I am doing a 660). so I have a couple of questions..

1) What is Analag using for R15 in his 660?

2)Also, when did we go from 6.3 to 9V? Is this specifically for the 670?

This is what Analag said his power trafo is :
250V @ 80mA, 15V @20mA and 6.3V @3A.

Is Analag using the bypass boards?

Finally, the toroid I am looking at (Antek 1T250, someone mentioned this here or in the "should I" thread but gave the wrong specs) is 2x 250V, 250mA each ,2x 6.3V 3A each.

Can I get +18 and -18 from one 6.3V 3A secondary... or wiring the two together, but I think it~s not a good idea to mess with the heater voltage.. . I don't want to buy two toroids for this, so I may ask to build Antek if they can custom do one, but no idea if they do that. Unless you think it'll work with this one (with bypass) I will have to keep looking. Thanks for the ideas..


On a side note, I traded a few emails with Laura at TAW about their products in general and Wimas specifically. She will probably appear here herself at some point, but for the time being she has offered anyone from Prodigy their 100+ pricing on small orders... The 10uF MKP4's turned out to be $4.15. I ended up ordering all the Wima's I need now, for much less than Mouser, plus all the Panasonic electrolytics which are also a few cents cheaper than Digikey. I'm gonna post this in the BM for those who want to take advantage.

 

[emrr]

[quote author="flintan"]Ok, thanks! Is the two windings just soldered to the centertap lug? Then it would be quite easy. :grin: [/quote]

yes they are

But on second thought, i wonder if the Edcor windings are close enough matched for this type of application..

if they are close enough to be useful at all, they should do the trick. Maybe not ideal, but close enough for a PM. You could always go with an appropriate $$$ transformer set instead.

 

[khstudio]

2)Also, when did we go from 6.3 to 9V? Is this specifically for the 670?

It's for DC on the Heaters

CORRECTION!!!

Sorry... I was half right

 

[emrr]

2)Also, when did we go from 6.3 to 9V?

It's for 6.3 VDC, rectified from 9 VAC.

 

[shabtek]

those who have the boards:
those 10u caps are 10mm spacing? correct?

[silent:arts wrote:
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.
----------------------------

 

[mitsos]

Darn you people with your 1000+ posts! Who do I believe now?!?

[quote author="mitsos"]2)Also, when did we go from 6.3 to 9V? Is this specifically for the 670?

[quote author="khstudio"]
It's for DC on the Heaters... it gets rectified 9v x 1.4 = 12.6v[/quote]
[quote author="emrr"]It's for 6.3 VDC, rectified from 9 VAC.
[/quote][/quote]
Kevin's answer makes sense for the stereo (not my case). you'd need 6.3 per channel right? So 12.6?

But emrr got me thinking, after the 6.3 gets rectified, I'll have (let me pull out my complicator) 8.91VDC or so. Ok, that's where the 50W resistor comes in to drop the voltage? Am I on the right track? I've got a long ways to go. Lucky for me I don't have all the parts yet.
Well, tomorrow I will see about the custom toroid, if anyone has ideas on how to use that stock one, let me know.

Thanks!

 

[emrr]

It's 6.3 VDC no matter how many channels.

 

[mitsos]

[quote author="shabtek"]those who have the boards:
those 10u caps are 10mm spacing? correct?
[/quote]I don't have the boards. Mouser lists them at 37.5mm and when I checked Wima's site the only one they have is 37.5

Thanks for that quote.. It's hard to straighten things out since most people are doing stereo versions.. Anyway, I'll get there.

 

[emrr]

[quote author="shabtek"]those who have the boards:
those 10u caps are 10mm spacing? correct?
[/quote]

The Wima? 37.5 mm lead spacing, 19 mm body width.

 

[khstudio]

mitsos,
Sorry. Doug is right 6.3v DC.

I'm working on several projects here & got confused... one is a preamp with 12v DC on heaters.
Not to mention I don't even have a schematic yet, so...

Mouser is out of stock for the 10uf

Google - Search for TAW... find their site & call... they have them.

 

[[silent:arts]]

Doug is right :thumb:
thanks for your support, if there are some PCBs left I owe you a set for the support you do here :thumb:
easier to send then some :sam: :guinness: :sam: :guinness: :green: :green: :green: