the Poor Man 660 support thread

[[silent:arts]]

a copy is already on its way

 

[melville]

Amazing! Thank you Volker. Wasn't sure if you'd seen my pm or not. Can't wait to get this finally built.

Thanks again

 

[melville]

Got the replacement poorman schematic through the post today. Thanks Volker. Speedy service. Now I can finally crack on with getting this built. No mods just stock as it was originally intended.

 

[dagoose]

Just wondering, if you would upgrade the input iron, what would you choose? The edcors are OK, but i'm not 100% satisfied with OK.
I'd like the sound of lundahls myself but like to try something else for a change..
anyone?

 

[noulou]

Just wondering, if you would upgrade the input iron, what would you choose? The edcors are OK, but i'm not 100% satisfied with OK.
I'd like the sound of lundahls myself but like to try something else for a change..
anyone?

I put utc a26s reversed in mine and LOVE it. MUCH better than the Edcors. quite a bit more gain though.
Works great in mine but I have upped the 6n5ps b+ voltage.

I have also been thinking of using the carnhill 2291 as a 8:1 stepdown to compensate for the increased gain

 

[skal1]

hi  lads just been checking the schematic around D1,D2,D3 and D4 four compared to the pcb ,it seems that either the schematic has an error or the the pcb has an error, which one is it

According to the schem D3,D4 cathodes are connected together , when looking at the pcb D3 and D4 anodes are connected .

Or i am i missing something .

Just want some clarification on this ..



still a newbee at heart

Cheers skal1

 

[[silent:arts]]

Cool, you are the first finding this out 8)

I just checked it: there is a little silkscreen error on the PCB:

D3 is in reality D1
D1 is in reality D3
D2 is in reality D4
D4 is in reality D2

since all are 1N4148 this doesn't really matter.
but good to know you are comparing the schematic with the PCB.

 

[skal1]

8)

skal1

 

[skal1]

ok just rebuild my psu after 2yrs it works with no load , then i connected the psu to the to 1 of the amp cards and hay presto it blow the power supply up .

so i have rebuilt it again and it works.

what on the amp card can keep blowing the psu, i have checked the switches and the tx op and sc they measure alright i think.

need some help on this lads

cheers

skal1

 

[king-rb]

hi all together. i rewired my poorman to make the error tracking easyer. now its working and i like what it does but there are problems with the frequency response. what can cause such a bad frequency response?
also what can cause this distortions in the signal?

 

[skal1]

ok i have made some head way with the psu it is now holding  up , but i have some sort of motorboating on the out put of the amp stage.

the only thing i have done differently is to mount the irf off board on to the case insulted of course.

Anybody got an idea

skal1

 

[radiance]

Just wondering, if you would upgrade the input iron, what would you choose? The edcors are OK, but i'm not 100% satisfied with OK.
I'd like the sound of lundahls myself but like to try something else for a change..
anyone?

Kingston got great results with the Lundahl  LL1676. You say you don't like the sound but maybe it's the "Lack off" sound?
I don't see any reason to make my poorman cleaner by adding Lundahls...the whole reason for building this was added distortion

 

[dagoose]

Just wondering, if you would upgrade the input iron, what would you choose? The edcors are OK, but i'm not 100% satisfied with OK.
I'd like the sound of lundahls myself but like to try something else for a change..
anyone?

Kingston got great results with the Lundahl  LL1676. You say you don't like the sound but maybe it's the "Lack off" sound?
I don't see any reason to make my poorman cleaner by adding Lundahls...the whole reason for building this was added distortion

I like the distortion indeed but there is something really subtle going on in the lowend that i don't like and i think it will be solved with different tranny's. I had the same thing with my d-aoc, edcors lacked some tightness in the low-end and that was totally different with lundahls on the input. It opened up the sound completely the way the edcors could not. Going to check the ll1676, always like the sound of lundahls

 

[coffeeman]

Any chance of buying a set of PCB's just for the Pm660 (actually 670 as mine is a dual channel). I recently bought this from someone in the black market 'with a fautly channel' but it seems the one pcb was kind of 'buthered' and the other has some issues that I fail to find. I have spent days checking every connection and every resitors, capacitor, tube socket, voltages ... you name it I have checkedit but I cannot find the fault anywhere... so I have decided to put the mainboards together myself and redo the stepped swiches (which also have issues) but I need new PCB's as I simply cannot use those that I have now.

Any remote chance of a pair? ??? Thanks for letting me know.
Cheers.
Craig

 

[radiance]

Going to check the ll1676, always like the sound of lundahls

Let me know when you're buying these...& if you've found a cheap source...man these ARE expensive:-(

 

[dagoose]

Going to check the ll1676, always like the sound of lundahls

Let me know when you're buying these...& if you've found a cheap source...man these ARE expensive:-(

wow... 125 euro for 1.. 

 

[radiance]

Going to check the ll1676, always like the sound of lundahls

Let me know when you're buying these...& if you've found a cheap source...man these ARE expensive:-(

wow... 125 euro for 1.. 

All other input options (except Edcor) are in this price range...I checked Sowter, UTC , Triad...

 

[Kingston]

Who says you have to run the input 1:4? All it does is artificially limit input impedance to 600 ohms and give you 12dB of gain you do not need. Input attenuator is right after the transformer so gain staging is a non-issue. Just give it a bit higher input signal with lesser ratios.

There are plenty of other very high quality options 1:2 and especially 1:1.

 

[radiance]

Who says you have to run the input 1:4? All it does is artificially limit input impedance to 600 ohms and give you 12dB of gain you do not need. Input attenuator is right after the transformer so gain staging is a non-issue. Just give it a bit higher input signal with lesser ratios.

There are plenty of other very high quality options 1:2 and especially 1:1.

Yes, but does that mean you'll have to rethink the attenuator resistance value to still have a sensible range?
Cause there's no way I'm going to redo those Elma's ..

 

[Moby]

Who says you have to run the input 1:4? All it does is artificially limit input impedance to 600 ohms and give you 12dB of gain you do not need. Input attenuator is right after the transformer so gain staging is a non-issue. Just give it a bit higher input signal with lesser ratios.

There are plenty of other very high quality options 1:2 and especially 1:1.

Yes, but does that mean you'll have to rethink the attenuator resistance value to still have a sensible range?
Cause there's no way I'm going to redo those Elma's ..

I run my PM660 with custom 1:3 input tx and it works like a charm without any attenuator mod