Bottlehead Crack built question

[Wplchou]

Hi guys, this is my first DIY electronic project and i have a ques re the res checks, so everything checked out except terminal 7 and B3, which is connected. I dont know if its my really cheap DMM, i realized for other terminals i need to hold the probe steady for a while (like 5 seconds) to get a reading. I did re-solder the joints at 7U and B3, i have a solder suction thing which im not sure if im using it correctly cos it cant really remove the solder on the joint too well, but still it doesnt check out. Think I will get shot saying this, but I went ahead with the voltage check, it was smoking , and had a few sparks coming off the unit when i first turned it on for the check, but after a while it stabilsed, and all the voltage actually checked out! and even better, it works and it sounds beautiful.

I am hesitant to go ahead with the speedball upgrade (partly cos it sounds so good already i dont wanna risk breaking it) which I also bought, so my question is, is it possible that the res check failed and voltage checks out and amp works? and i also notice the aluminium chassis gets really hot, like i know tube amps especially the tubes are meant to be hot but i think the chassis is almost too hot to touch is that normal?

[Thermioniclife]

Do not run an amp that has not passed a resistance check! What was the resistance from 7u to ground? what is the resistance from b3 to ground? they should be the same. 2.9k ohm. If shorted to ground this must be addressed. If the wire from b3 to 7u is not connected well it could arc and smoke and possibly make a temporary connection. Is this the area that sparked and smoked?
As I stated earlier you must address this issue before continuing.

[Paul Birkeland]

Please post some photos of your build. 

[Wplchou]

Thanks for the replies i have attached some  photos of my build

[Paul Birkeland]

The 10K/3W resistors are not properly connected.  I would suggest reviewing page 43 of the manual and the installation instructions. 

[Wplchou]

The 10K/3W resistors are not properly connected.  I would suggest reviewing page 43 of the manual and the installation instructions. 

actually just as i took those pics again i did the test checked out for those two terminals and the rest also fine... strange.

Paul thanks for the reply , on page 43 it says crimp the leads into place, doesnt it mean what i did there? but actually i realised in the photos looks like the leads on all 7L9L and 3U were "trimmed" as well after the resistors are in place, is that what you mean but not properly connected? should i just trim the leads on the 7L9L and 3U which are sticking out?

[Paul Birkeland]

From the bottom of page 43:

Gently pull the leads inserted into 7L and 9L
taught and crimp them into place on their
terminals.

You need to pull these leads tight, one of your resistors looks like it is very close to touching terminal 8.  If this happens, one half of the 6080 will attempt to draw as much current as it can until it melts down your amplifier.  You would also get a bad resistance reading at that terminal as a warning not to turn your amp on.

[Wplchou]

From the bottom of page 43:

Gently pull the leads inserted into 7L and 9L
taught and crimp them into place on their
terminals.

You need to pull these leads tight, one of your resistors looks like it is very close to touching terminal 8.  If this happens, one half of the 6080 will attempt to draw as much current as it can until it melts down your amplifier.  You would also get a bad resistance reading at that terminal as a warning not to turn your amp on.

you are right it does look very close to terminal 8 which is probably why initially the res chk didnt clear. but if it is now, and I am going to go ahead with the SB upgrade which i read on the manual says that i have to eventually remove the 2 resistors, i may as well go ahead with the upgrade.

on that note, can i also ask re the upgrade the 22.1K resistors and the 10k/3w resistors when i remove them i just clip the leads off instead of desolder them off correct?

Thanks

[kGlerup]

If it's your first build of this kind, then wait a bit with the SB upgrade.
Get the basics done first and enjoy the amp (you will!) for a while.
If you have any lingering issues caused by failing soldering joints, you would want to have that sorted before dropping in the SB!

[Paul Birkeland]

you are right it does look very close to terminal 8 which is probably why initially the res chk didnt clear. but if it is now, and I am going to go ahead with the SB upgrade which i read on the manual says that i have to eventually remove the 2 resistors, i may as well go ahead with the upgrade.

Please don't.  Is the amp even working?  I would suggest correcting the build issues you have and using the amp for a month to be sure it's working properly.  At this point if you install the Speedball and run into any issues, I will be suggesting that you remove it and reinstall the resistors to ensure that the stock build is working properly.

[Wplchou]

Please don't.  Is the amp even working?  I would suggest correcting the build issues you have and using the amp for a month to be sure it's working properly.  At this point if you install the Speedball and run into any issues, I will be suggesting that you remove it and reinstall the resistors to ensure that the stock build is working properly.

Yes the amp is working fine I will take your advice to use it for a couple of months before upgrading to SB. Thanks!