the Poor Man 660 support thread

[[silent:arts]]

The Elmas are a good choice.

 

[wmarden]

The Elmas are a good choice.

I thought the Elma's were the ones that failed?

 

[[silent:arts]]

My Elmas never failed, but I can't talk for everybody.

 

[HerbertR]

Hi, can anyone confirm if I can also use for the Poorman Filament Heater PSU as for the "Tweak" Voltagedrop Resistor R15 two Voltage Divide-Resistors?
Is there a disadvantage to use Resistors in this way instead of serial use in this simple unregulated 6.3V PSU Circuit? I think my calculations should be correct...
And I have this Resistors laying around...Thank you for your help

 

[HerbertR]

My Poorman Baby is ready. Its running pefectly. It works from the first Minute perfectly. I ve expanded my Unit with Wayne Kirkmans M/S Matrix PCB - first class...Fantastic sounding piece on nearly everything - especially on Sum/Bus applications. The signal stays clean, gets gentle density, nearly always excellent results Awesome. I have not testet the Lundahl 1540 as for InTX I have laying around - only with Edcors till yet. Amazing piece. Big thanks to SilentArts, Analag and Wayne Kirkwood...

 

[HerbertR]

I want to share my efforts I ve done to get my Poorman at the first moment without any problems working:

-I am employing an extra 50VA 9V secondary PSU terroid including the same unregulated Filament/Heater 6.3VDC PSU Circuit for each channel seperate. I ve solderd this easy Circuit on a Blank PCB. It consists only from 5 Parts. Trace the Components on the PCB or search for this easy "standard" unregulated Heater Schematic in this thread. Every channel pulls about 3 A. As for R15 "Tweakresistors" I am using 1.3 Ohms divided in two 100W resisitors for external mount on the case. And they also get really warm to get the Voltage from about 9,8 VDC after the bridge-rectifier to about 6.3 VDC. If you use only a 25W Resistor it gets really hot - but its also enough not to override this resistor. But I would not use value. I have also increased the two ripple Caps C21 and C22 from 4700uF to 10000uF for each channel to achieve a smoother ripple

-my RCA 6BC8 are a matched quartet, also the Sylvania 5687 are a matched quartet - its really hard to find some sources out there nowadays - mine are from DB Tubes in Canada - no noise, very close Outputlevel / Compressionlevel on both Channels

-I replaced the wrong Cap C6 in the HT B+ Rail from 47uF to a 0,56 uF (Analag said 0.47 to max 1.0uF ) Film Cap with 630 Volts

-R1"Tweak Resistor" in the HT B+ after the Rectifier should be Offboard. The 47Ohm 2W were way to low to tweak the the Voltage from about 360VDC after the Diode Rectifiers to about 310-320 VDC. I ve needed 700 Ohms and used this divided on three 10W Resistors to decrease the Voltage for booth Channels to about 315 VDC down. Then the first IRF 840 gets only warm with the standard heatsink - I am useing also on Q4 the recommended IRF840 instead of the IRF 820 including Ceramic Insulators between the regulators and the heatsink. Safety first...

-I really recommend a MS Matrix... Its amazing! Wayne Kirkwoods Version employs not less than 16 THAT IC Opamps to compensate all Leveldrops during the summarize and subtraction processes due encoding and decoding. To switch the Output correctly between M/S and L/R and additionally directly "encoded" M/S out I ve used 16 Relays on cheap Relayboards. This 150 Bucks Upgrade is worth every penny

Have a nice

 

[fragletrollet]

Very nice build HerbertR!

Are you using the MSMini from KA? I got one of these boards to use in my D-AOC, and am curious how you implemented in your build. Is it always M/S, or is it switchable L/R and M/S? I am wondering how I should perform the switching between the two, if It's necessary to switch both inputs and outputs from the MS board to the bypass boards, or just the input to either MS board or direct, and leave the outputs permanently connected to the bp boards (effectively connecting two outputs together (bad?)). A little drawing would be helpful!

 

[HerbertR]

Very nice build HerbertR!

Are you using the MSMini from KA? I got one of these boards to use in my D-AOC, and am curious how you implemented in your build. Is it always M/S, or is it switchable L/R and M/S? I am wondering how I should perform the switching between the two, if It's necessary to switch both inputs and outputs from the MS board to the bypass boards, or just the input to either MS board or direct, and leave the outputs permanently connected to the bp boards (effectively connecting two outputs together (bad?)). A little drawing would be helpful!

Hi,
It is really easy and yes it is the MS Mini Board from KA. The LR->MS Encoder and the MS->LR Decoder are independed on the MS Mini Circuit. Make all In/Out Signals from Hot/2/+ and all Signals from Cold/3/- with a Relayboard full of SPDT's.... switchable. As Example ...without Trigger Voltage on the Relays feed the external In LR Signals directly through as Bypass to the Compressor PCB and the LR Output from the Compressor to the XLR Outs. Or feed the MS Board inbetween with them and convert the signal . You can also switch In and Out independed like you want and so you can also use only the Encoder or only the Decoder. So you could have the oportunity to feed the Compressor with an MS Signal at the Input XLR or send the MS Signal without Decoding to the Output XLR ... There are a lot of options...
The Board addtionaly has Jumpers directly to decrease or increase the Mide or Side Level on some points with +6 or -6dB. Make the Jumpers switchable with simple Toggle SPDT Switches on the Frontpanel. So you can increase or decrease drastically the M or S Signal and go as example hotter with the Side Signal in the Compressor....
Ready built Relayboards can be bought on EBay, Amazon... for about 20 Bucks with 8xSPDT Relays or more ...As for the trigger Voltage it depends on the available Voltsges. I ve used the 12V DC Rail - 12V Relays feeded to a Lorlin 4X3 Rotary Switch (called AGC on my Frontpanel) . I am Switching with one Pole of the four Poles of the Lorlin directly 2x4 shorted/connected Relays or 2x8 shorted/connected Relays at the same time. It is so easy and cheap. The used THAT ICs are also a class itself, .... You have so a lots of possibilities....

 

[fragletrollet]

Thanks a bunch.

 

[FarisElek]

I'm very impressed with the results of your build. I'm tempted to restart this project

 

[Bernardo]

Hello, does anyone know where I could buy the pcb v.2 and the psu?maybe some gerber??Thank you

 

[BGroen]

Hello, does anyone know where I could buy the pcb v.2 and the psu?maybe some gerber??Thank you

Any luck? I'm also interested !

 

[idylldon]

A quick question. When in stereo mode, which set of controls are used, left or right?