k12-m amp not working

[arairkar]

Hi Guys,

I am new here and am a novice at this. I have a S5 electronics tube K12-m tube amp , the right side of which has stopped working. I am sure it has been discussed here before and in parallel I'll search the forums, but thought I'd post as well to get some input.

My friend gifted me the kit and I put it together as-is in the basic form and connected it to a pair of Quad 21L speakers with blue heaven nordost cables about 3 years ago. It sounded pretty good for a year or two and then I had to move a few times. I now tried to assemble it again and the right side has stopped working. All 4 tubes glow , so I am inclined to not suspect the ceramic holders but could be so. I am thinking that one of the caps or resisters is busted or I short-soldered something (my rookie bad)

Here are few problems I'd like to solve towards attaining music Nirvana-

1. I'd like to figure out and fix what is wrong with the right side and fix it.
2. I'd like to add a remote digital volume control to it
3. I'd like to add functionality to do multiple inputs with a digital or analog switch (dvd player, ipod, computer etc) so that I don't have to disconnect and reconnect the input cables everytime.
4. I'd like to better its low frequency range. I read somewhere that beefing the capacitors helps
5. Built a basic but nice looking enclosure for it and make it safer
6. Get a DAC to connect computer / dvd player digitally /optically?

Lastly, do you guys think I should start over with a new kit rather than try to troubleshoot this one.

Really appreciate your input/tips and time.

[Pano]

Welcome to the forum. To address a few of your concerns.

1. There will be plenty of troubleshooting help here, but tell us more about the amp and provide some info in links if you can
2. Get a preamp
3. Get a preamp
4. Maybe you can help with caps, but you'd better know what you are doing. You may be bass limited by the output transformers
5. Good idea!
6. There are plenty to choose from. Got a budget?

Other members will soon chime in with help and suggestions.

[arairkar]

Thanks Pano,

Here is the amp I am talking about

S-5 Electronics K-12M Tube Amplifier Kit

I would hope to have a budget of $200 or less for the DAC. Is there a kit that has a preamp/dac built-in.

-Asit

[Soonerorlater]

1. I'd like to figure out and fix what is wrong with the right side and fix it.

Need to know for sure you don't have a faulty tube. Try swapping the right hand pair of tubes with the left. If the fault moves with the tubes then one at least is faulty and will need to be replaced. Have you any spares?

Brgds Bill

[chrish]

Not sure about the trouble shooting, but if you are going to put it in an enclosure, these links to some epay items might help you make it in to an integrated amp:

eBay Australia: Buy new & used fashion, electronics & home d?r

http://www.ebay.com.au/itm/320771322...ht_4237wt_1114

eBay Australia: Buy new & used fashion, electronics & home d?r

[arairkar]

I moved the tubes and speakers/wires. The problem didn't move with any of those indicating that it is something wrong with the right side of the circuit.

Thanks for your fast responses

[Soonerorlater]

A visual inspection would be my next move, particularly resistor R8, is it discoloured or burnt compared to resistor R17. If nothing unusual turns up then you might have to take some measurements with a multimeter if you have one.

Schematic - post 5 K-12M Enclosure + Upgrades. Finished!

[Richard Ellis]

Roll some tubes in these...........It is just so cool to swap out tubes & watch systems fail. My first , swapping TV tubes . I had a good lock on the signal , but no color. The 12AX7 was common, so I traded a lock for color.........So here was this color signal just floating . Out of lock for horizontal & vertical...showing multiples...*************

__________________________________________________ __Rick...........

[chrish]

Did you re-solder any components when you took apart and re-assembled? Look for unintentional solder bridges. Also check that any components on wires that the wire has not frayed/broken - check with meter. Also, I just spent hours trouble shooting an active crossover that had a broken trace on the PCB, but it looked normal. After you have done this, next thing will be to check the voltages comparing the good side to the bad. Do you have a multimeter? Troubleshooting without at least a meter is going to be difficult if it is not an obvious broken wire/trace/solder bridge.