HOLDEN/WASP

[sluckey]

When the relay is off the LED is on and there is 18v across the switch

Are you sure? That's a lot of voltage to come from a 6.3VAC filament winding!

Remove the diode and cap that are parallel to the switch. Does that help?

[TIMBO]

Hey Sluckey, The power supply is tapped off the power tube heaters and measure approx. 13v. I thought this was a good source of power seeing that the relay doesn't draw much current.
Thinking that it was a problem to use the heater tap I used a small transformer and had the same problem.
I also removed the cap/diode and just had the LED and it presented the same problem.
Anyway i'll recheck things.

[sluckey]

Maybe try a different type relay?

[DummyLoad]

relay latches - won't release b/c of current flow thru LED, even when switched off. if i fiddle with 120R in your schema, i can get it to work in simulator, but not reliably.


--pete


EDIT: i used 56R for 120R and 220R for 470R.  assumed 100mA 5V coil w/ DCR of 50 ohms @ 110mH. 

[TIMBO]

Hey pete, these are the same relay I have used in all my builds. http://www.jaycar.com.au/productView.asp?ID=SY4052
With the 120r is pretty close to 12v across the coil when the relay is on.

[TIMBO]

Hey DL, Paralleled the 120r and it did nothing.
For what ever reason the LED/resistor is stuffing things up.

I increased the LED dropping resistor to 1k5 and this has done the trick, also there is no lost of brightness in the LED.

[DummyLoad]

Hey DL, Paralleled the 120r and it did nothing.
For what ever reason the LED/resistor is stuffing things up.

I increased the LED dropping resistor to 1k5 and this has done the trick, also there is no lost of brightness in the LED.

the trick was to get the relay OFF state current through the LED low enough for the relay to drop out. glad you got it sorted.


--pete

[DummyLoad]

sim of you problem. the first two screen captures show a working circuit with 1500ohm dropping R. the third screen capture show shows the latched state of the relay with a 470 ohm dropping resistor - i had already toggled the one the switches off to on to off - notice both LEDs stil it.


the relay values were estimates taken from an omron datasheet. i estimated the coil pickup at 75% of maximum and coil dropout at 20% of max. 42mA is maximum @ 12V.


--pete

[TIMBO]

WOW, that's impressive.

[TIMBO]

Hi guys, Down to the last few questions.
I noted that here http://el34world.com/Forum/index.php?topic=17556.0 the boys have adjusted the grid leak via the pot/resistor to match the resistors on the original major.
The Wasp had 100k resistors and the usual 250k pot/2.2m resistor combo is what I used, I have read that this could be a problem. Its seems to work as I have it.

After having the amp on for a good while I checked the main Ecaps after switching off. There was still voltage but if slowly bled of over a short time down to about 110v and the preamp Ecaps are down to 0v.
So 220k/3w across both Cap cans be enough?

The local guys also mention a 150k/3w across the standby sw. as a switch saver??

And that my friends is just about that.  

[DummyLoad]

So 220k/3w across both Cap cans be enough?

absolutely. use 330L or 470k as well if you wish - just a longer discharge time constant.

with 700V on the plates, i wouldn't even have bothered with a PPIMV. simple is best. 2.2M isn't going hold for long if one of the pots wiper opens.

use a 180K || with 250K pot. R is then ~105K full up (as it was) and if a wiper opens up it's 180K: much, much better than 2.2M grid leak.

no opinion on the standby saver.

--pete

[TIMBO]

Thanks DL, On it.

[TIMBO]

Hi guys, The Holden wasp is done.
I'm very happy the way it has turned out.
The two channels are very useable as they are.
Channel 1 is very clean even up to pretty max volume and could take a pedal in front well.
Channel also has a nice blues breakup at higher volume and the two channels can be jumpered to add some extra gain.
To OD kicks it up a notch and adds some great overdrive that is not too over the top.

I'm trying to convince someone local here to do a demo as I couldn't do it justice.

 

[DummyLoad]

very nice work! :-) 


--pete

[Willabe]

Looks great Timbo!!!!!


             Brad       

[terminalgs]

very cool.

[tubenit]

Very impressive and a great job!  THANKS for sharing the photos and info.

With respect, Tubenit

[tubenit]

I thought I'd try to convert this to an easy to read GIF file so others could see what a great approach Timbo took to this build.

With respect, Tubenit

[TIMBO]

Hey Tubenit, Thanks for that. Just a small change. I used a 180k with 250k pot for the PPIMV. This was a suggestion from DL, as this now makes the grid leak similar to the original 100k resistors.

EDIT: Corrected this in the above post


I also added 390p caps to the 100k plate resistors on the OD. This did add some smoothness as well reduced some ghosting of the notes. Thanks

[Ritchie200]

Wow!  That looks like it just came off the music store shelf new!  Very nice job!  You should be proud of this restoration.


Sound clips?  Go ahead, you can do it!  We have all made fools of ourselves in the Sound clip section, join the club!


Jim

[TIMBO]