It is currently Mon Mar 16, 2020 8:55 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 56 posts ]  Go to page 1, 2, 3, 4  Next
Go to page 1, 2, 3, 4  Next
Author Message
Post subject: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 7:00 am
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Hi guys,

I asking for help, please.
I'm building amps for my pleasure, I'm far from being an expert.
I'm just having fun, doing my best.
After building some 5f1, bassman etc ... I'm building a 6G15 Reverb.

I have an issue and the picture here will explain it all.
I have half the expected voltage on a turret. All the other surrounding points are ok.
Bad resistor ? I think I didn't make any mistake with resistor ...

I don't have yet the skills needed to make a diagnosis.

Here is the pic of the issue. Any help will be precious.
I also included a pic showing the entire project (I did everything, incuding the boards etc ...).

Image


Image


Thanks a lot

Vincent


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 8:22 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Are those two resistors 22 meg instead of a 2.2 meg? I can't tell if the third band is blue or green. :?:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 9:36 am
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Hi Shimmilou,
Thanks for your answer.
Well, the color is GREEN.

Vincent


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 10:11 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
OK, 5 it is, that's correct. Do they measure 2.2 meg on a meter? No need to remove them, you should be able to read very close to 2.2 meg on each. After checking the resistors, remove that 12AX7 and check the voltage with the tube removed. I would expect higher than 120 VDC with the tube removed, if it is a tube problem, and everything else is good.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 10:29 am
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Yes, they are both 2,2M, checked with the MM.
Now I'm running the second test you proposed.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 11:44 am
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Well ... I'm lost.
Even without the 12AX7, I still have 60 V instead of 120.
Same without the 12AT7 as well.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:18 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Wrong bias on your 12XX7 tube ?
Or short.
Remove tube , look if voltage go up


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:26 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Hi
I do it again, to be quite sure.
Last time I did it, still same voltage (60 instead of 120).
I'm building the 6G15 based on triode schema (http://site.triodestore.com/6G15ReverbLayoutV2.pdf) and I'm checking the values according the fender schema (http://i.imgur.com/8Ofqn.jpg) or the weber schema (http://www.diyrecordingequipment.com/wp ... layout.jpg). Both are showing 120V.

The only change I made is a full wave rectifier (diodes) and it works well (delivering the right DC voltage).

Rechecking the 12AX neighborhood now.

Thanks


Ps : should I install a 1,1M resistor in place of the 2,2 in order to jump the voltage to 120V (I'm currently having 60V).


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:31 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Remove the 12AX7 tube and read voltage
Bad solders, do a good ones ( many )

Do you have lots experience in soldering ?

Ps , NO


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:38 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Removed 12AX7.
Re checked all wirings connected to it.
Checked if short circuit between the tube socket (they are tiny) : no, clear. I spaced the wirings to be sure.

Voltage is the same : 60V instead of 120V
On the other resistor, at the right, I have 160V which is the expected voltage.
I already changed the 2,2M resistor and put a new one (same value).
Still 60V.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:41 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Regarding soldering, I think I do honest things.
You can have a overview of my solderings in the pics I enclosed.
If you consider this is crap, I add some extra soldering to all the turrets.

Btw, I soldered twice the turrets for the "faulty" 2.2M resistor. Giving extra solder in the turrets.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:47 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
vince_fr wrote:
Regarding soldering, I think I do honest things.
This do not answer to my question :(

You can have a overview of my solderings in the pics I enclosed.
Yes I do , poor :lol:

If you consider this is crap, I add some extra soldering to all the turrets.
I did not say that :lol:

Btw, I soldered twice the turrets for the "faulty" 2.2M resistor. Giving extra solder in the turrets.

Soldering the good way need lots of practice. We all begin like that .



Why don't you remove the *** tube and read voltage ?


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:55 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Apr 07, 2014 5:53 am
Posts: 32
Ok I'll practice !

I did remove the tubes and still read the same voltage.

What s curious is that I have exactly half the expected voltage : 60 instead of 120.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 1:59 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
vince_fr wrote:
Ok I'll practice !

Great , pratice on old pars , wire

I did remove the tubes and still read the same voltage.

Strange...there is a short there ???? Something wrong , look carefully .
remove all tubes

What s curious is that I have exactly half the expected voltage : 60 instead of 120.


Top
Profile
Post subject: Re: Home made 6G15 issue with voltage
Posted: Sat Jun 21, 2014 2:01 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Any drop of solder on tube's socket to chassis = short ?


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 56 posts ]  Go to page 1, 2, 3, 4  Next
Go to page 1, 2, 3, 4  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: