LEAK 20 VALVE MAINTENANCE

[Batman]

Hi Guys

I've finally made time to get my QED phono cables yesterday to connect the Leak 20 via pre-outs on my NAD receiver. The hum that I was getting from the ceiling fan is now gone, obviously due to better shielding on the phonos and not an earthing problem. Even if I put my nears next to the speakers there's no noise at all. This little amp is truly a gem. It hits well above its 20w power rating with ease and sounds wonderful

@ Peter, you'd mentioned that the left and right input were swopped around but I don't think it is. I'd spent most of the day untangling my cables behind the tv unit to make sure I'm not going crazy. I have pink noised and triple checked everything.

Now to the nitty gritty ...... how do I maintain and service a/this valve amp to keep it going for another 50 years. I'm in Durban so if you'll can help locate reputable technicians it'll be helpful.

[mafioso]

I don't think there was a Leak 20. You must have a Leak Stereo 20.

Very nice and famous little amp.

mafioso

[mahleu]

Steve Parish in Dbn North is apparently useful with valve, haven't tried him yet. I need to phone the guy I bought my Stereo 20 from who said he had someone good as well.

One thing is to check the 100ohm, three-watt safety resistor (normally green in colour) is still fitted at the base of the board near the transformers. If it has been bypassed or replaced with anything bigger, then it needs to be swapped back to original. It protects the main transformer if there is a major short.

One thing I want to do is replace the Pre-in plugs with some shiny new ones which I have. It looks like it might be a bit of work though as the main board is in the way.

[Batman]

Is there any indicators for the need of a service that I need to look out for?

I don't think there was a Leak 20. You must have a Leak Stereo 20.

Very nice and famous little amp.

mafioso

Lol

@Mahleu, I've still got the pm you sent me with his number.

[Kent Kassler.]

....i have a Jack Johnson cd that starts off on the left channel only and when i had the rca's connected left on the left and right on the right on that amp the cd would swop to the opposite channel when starting to play....i could be nuts though ;DEvery component with the exception of the input connectors was replaced on that unit so guess what.....she's ready for another 50 years already.....all parts were sourced from RS Components and they were precisely what the original was specced with.....enjoy! ;)I did not want to change the connectors for new ones....that would spoil the oldskool look for me.

[Batman]

Thanks Mahleu will have a look and see.

Peter, one of us is more nuts than the other but which one is it? I've connected everything as per their labels. Its a weird design on the back where the front and right speakers cables have to cross each other.

[Kent Kassler.]

Batman....i think we're confusing each other here....let me try and explain....i am assuming the amp is facing you front on!On the right,top front are the two input connectors to which you are running the rca's from your Nad.....assuming that you have connected the speakers left to the leftside rear of your amp and right to the rightside rear then the input rca furthermost left is actually the right input.....you with me?Even i'm confused.....this is fun in a sick,demented kinda way

[Kent Kassler.]

....just do a left right balance check or pop in a disc that starts on one particular channel then you'll know if you've got it right

[Batman]

Batman....i think we're confusing each other here....let me try and explain....i am assuming the amp is facing you front on!On the right,top front are the two input connectors to which you are running the rca's from your Nad.....assuming that you have connected the speakers left to the leftside rear of your amp and right to the rightside rear then the input rca furthermost left is actually the right input.....you with me?Even i'm confused.....this is fun in a sick,demented kinda way

Okay here's my view  ........................... I was looking at the amp from the front (i.e. transformer at far back). The top right corner as you'd said is the rca inputs. Left rca is on left and right rca is on right. Now, convention would lead us to believe that left input and left output should be on the same side of the amp but in this particular design its not. The left input has the right output on the same side and vice versa.

I've connected as per the labels all the way through and then pink noise tested to make sure. I was listening to an instrumental and I know for a fact it starts from the right and it was coming from the left so I found that odd and investigated.

[charles]

Dear Barman,

Glad to hear that your ST20 is now fully operational.

Regarding the 100 ohm green safety resistor. Ensure that it is soldered on the board in such a way that it can "unsolder" itself in case of a major short, etc. Do not twist the resistor's ends around the terminals. Hope this will help.

Regards

Charles 

[mahleu]

Dear Barman,

Oh no, you've revealed his secret daytime occupation. Batman will never be safe now.

[Batman]

Oh no, you've revealed his secret daytime occupation. Batman will never be safe now.

Lol

I'm a bit confused, how do I check the 100 ohm resistor to see if it'll solder off?

[charles]

Dear Batman,

I am not sure how to simulate such fault, that will ensure that the resistor de-solders itself. I will not be tempted to try it, as it could possibly damage the mains transformer. Best is just to inset the correct resistor.

Regards

Charles     

[mahleu]

Basically it should be able to drop off if the solder melts. The arms should just be straight so that it can fall unimpeded.

Lol

I'm a bit confused, how do I check the 100 ohm resistor to see if it'll solder off?

[Batman]

Basically it should be able to drop off if the solder melts. The arms should just be straight so that it can fall unimpeded.

Cool, will check