Heres a photo of the offending relay.

It's really easy to get this the wrong way around - it fits both ways.

Spotted by Nik - I looked for hours 

But once I changed this the amp was basically running in less than 5 minutes except for lots of adjustments....

Anyway - see the pic....

Thanks Hired Hand I appreciate your comments - it was my first build....

But I am usually good with my hands...

But not as good as you with the voltages 

Ill keep you all posted on this topic if I find any more stuff going on.

I had a 'funny' last night with the amp. After about 3 hours when it was hot the notes became distorted and I lost preamp output.

Im going to check forstly the tubes then for a dry joint - I suspect a dry joint. It was repeatable - I turned off for just 30 seconds and on again and the volume was back - for just a while while the amp heated again and then it lost the preamp (I reckon) volume again - distortion on the bass notes and then loss of output.


Ill let you guys know what I find for the record.

OK to keep the thread up to speed here's what I did next:

I spoke with Nik who said that it could be the associated boards around the amp (power, relay etc) which have been overtightened - apparently if you tighten them too much then you can get a similar problem especially if you use too much solder on the connections - it 'blobs' through the tag on the board, creates a solder ball and proceeds to distort the board when you overtighten it!

However, after slacking off all the peripheral boards so they were loose, it made absolutely no difference.. 

So, heeding what Nik had said, I removed (at least took the screws out) and checked the connections at the BACK of the boards one at a time. It is correct that you can get this solder build up - I found one on the rectifier board, but it was not causing any problems. I cleaned off the excess solder anyway.

But when I got to the relay board (the one that had the relay wrong way round) I saw a connection underneath (it looked perfect from above) the one with the red wire you solder to it from the main board - see my picture..  that had excessive solder under the board. This connection has a wire under the board that connects to something else and that wire was not a good joint. It looked perfect from above.


I resolderd that connector and cleared off the excess from the joint and rebuilt the amp boards to their original positions making sure I did not overtighten the boards.

AND IT WORKS!

At least for now - but I'm going to test the amp further and see if it hangs in there for a longer time. It worked last night for about 1 hour.

Lastly, Ill update this thread to help others - after all that's what this board is for....

I trust anyone reading this at any time will benefit from the insight of the build - and don't forget I'm developing a website www.overtonehrm.com which will show the build from scratch, it will go in to depth about things to get right and things which typically go wrong. It will cover the order of install (in my view) and it will show you on the amp what adjusters do what! Also voltages and any other quirky stuff with words, images and video of the head, the tail - the whole damn thing  as they say.

If everything goes to plan there will be another post from me confirming the amp is good.

Hi Hired Hand,

You are exactly right. I have in front of me right now a JTM45 board from the boys in the USA and the wires are all on the top of the board but under the components - it would be much easier to solve the problems if the boards were made this way. But of course, the Overtone HRM is a much more complex amp in my view against the JTM45. It's all those little boards and some of the stuff is a little funny, like the solder balls that form if you use a little too much solder.

It was a real pain to find actually. The result was much the same as if that relay was not there (like when it was fitted the wrong way around) and you know what - even the wrong way around, or when the connection was bad after reversing the relay, it still worked for about 4-5 minutes for some reason. I never got to the bottom of why that was so. Someone will know...  but it won't be me 

Yes I reckon actually the website should be very useful for anyone building one of the HRM's. There's lots to get wrong if you're not careful, and lot's to get wrong if you are careful.. 

Anyway.. thanks for your input throughout the time....

tonym