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Leben CS300XS not working - Help please

post #1 of 12
Thread Starter 

Recently bought a Leben CS300XS (100v model using a good quality stepdown tranny from 230v) which has worked great. The amp came with the stock Sovtek EL84/6BQ5 and GE 5751. 

Decided to do some tube rolling so bought a pair of Amperex bugle boy ECC83 / 12AX7, a nice improvement in SQ.

Next I bought a quad of Baldwin (sylvania) 6BQ5 black plates and on inserting these this morning the there was a bit of a smell from the amp and the operation lamp went out.


I can hear music but it is very, very faint and crackly. Have put the stock tubes back in just incase but it seems like the damage has been done.

It is looking like this is going to cost a few quid to sort out. Just wondering if anyone else has had experience with this and what it may be?


Any help is appreciated, thanks in advance.



post #2 of 12

using Occam's razor:


my guess is that the last tubes you inserted had an internal short. the smell could have been a screen grid resistor that got burned out when the tube shorted. the current surge that ensued may have been responsible for taking out the power lamp.


this is just speculation based on the sparse information provided, but not an uncommon scenario.


in any case, i wouldn't power it up anymore, as you could destroy more tubes and even permanently damage the output transformers.


i see no harm in removing the top and bottom covers, and carefully scanning for any visible damage, but do not mess around in there unless you know what you're doing. even unplugged, there are lethal voltages lying in wait.



post #3 of 12

I had a similar accident, at least symptoms are similar but my power lamp survived. Probably a few components are burned. I had a resistor burned and a capacitor damaged. I knew a good repair shop for tube equipment and it was inexpensive.


You can probably see the damage by removing the bottom plate on the Leben, but be very careful not to touch any components because of risk of electrical shock. However, this is not necessary and only for curiosity.


Don't power it on again because it could become more damaged. Leave it to a repair shop, hope you can find a competent tube technician. A Leben amp should be easy to service. It is point-to-point wired and no expensive components (except maybe the transformers).



post #4 of 12
Thread Starter 

Many thanks guys for the useful input. Have taken the bottom plate off of the amp but there is no obvious burned out components.


Will have to find a competent repairer in the UK after I come back off honeymoon next week.

post #5 of 12

Why wait? cancel the honeymoon to get your amp fixed! Come on, get your priorities right! biggrin.gif

post #6 of 12
Thread Starter 

Yeah I know Miguel, i'm a disgrace to the head-fi community deadhorse.gif

post #7 of 12

I'll buy it off of you for a door stopbiggrin.gif

post #8 of 12
Thread Starter 


And what will I use for a door stop then!

Originally Posted by cifani090 View Post

I'll buy it off of you for a door stopbiggrin.gif


post #9 of 12

I'll send you a very high end maple door stopbiggrin.gif

post #10 of 12
Thread Starter 

Just an update, got my leben back from repair and she is singing beautifully.


Apparently a resistor had blown so they replaced it and gave the amp a service, very pleased.


For anyone in the UK who might be looking for a competent tech for this kind of work:The Vintage Wireless Co. 174 Cross street, Sale, Cheshire, M33 7AQ


                                                                                                                            Tel: 0161 973 0438.


Alan Marchant is the owners name and he is a friendly, helpful and knowledgable bloke.

post #11 of 12

Congrats, and thank gosh, now i can buy you a real door stop! biggrin.gif

post #12 of 12
Thread Starter 

You would have only stubbed your toe on the volume knob.

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