VBITNGC building & comment

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I'm a little at my patience's end....

I can not get the voltage doubler to work properly....
I have a small traffo which is marked 2 x 22V, unloaded it measures closer to 26VAC, connecting the secondaries in series gives me 51VAC... when I connect this to the voltage doubler I get about 300VAC from rail to rail, with only one secondary connected I am getting 77VAC per rail (155V rail to rail)...

What did I miss? why no work? will make tube go boom?

EDIT:
Just had the thought to actualy measure DC... whell it still gives about 70VDC per rail.... is that ok?



I think this is the last thing, apart from refinishng the case, that needs sorting out... I had to make custom PCB's to fit everything in the amp's case (refurbishing) also the buffer is teamed up with a lm3886 in inverted config (courtesy of digi's pcb's - ya sorry I copied it with mah evil coki pen....)

Also is a 25second delay softstart enough? thats more or less what I get from my relay... Modification of the circuit includes 2 pilot lights which shows warmup and active status, by wiring 240V pilot lights to the dpdt relay. Input selector and LED display is done, and I believe the VU meter section should work, as I relaced all opamps and transistors on it... (acctualy I still need to figure out a powersource for it, but we are at 3 transformers allready....
 
My PSU in a Conrad enclosure with transparant cover (the child in me). tested and good. The amp is ready too, not tsted yet.

Gewa, how is your board doing?
 

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Hi Wim

Looks good so far. I'm curious how the amp testing will progress.
About my board: hmmm....., I binned the project to be honest.
Mainly because of the lack of intrest and secondly because I first want to finish all the rest I've got going on.

Regards
 
Nordic said:


EDIT:
Just had the thought to actualy measure DC... whell it still gives about 70VDC per rail.... is that ok?

.......

Also is a 25second delay softstart enough? thats more or less what I get from my relay... Modification of the circuit includes 2 pilot lights which shows warmup and active status, by wiring 240V pilot lights to the dpdt relay. Input selector and LED display is done, and I believe the VU meter section should work, as I relaced all opamps and transistors on it... (acctualy I still need to figure out a powersource for it, but we are at 3 transformers allready....

Hi,
provided your caps can take it +/- 70V are fine.

Also 25 sec should be enough to let the tube warm.

I have mine waiting to be encased but I've been delayed by my Aikido preamp (after all I already have a Amp3 and 2 My_Refs, so I wasn't so in a hurry).

Cheers

Andrea
 
Lol, wel I started on the 13th of Dec, and I'm only finishing now...
Cant wait to have easy source selection again.... 🙂

Caps are all 100V, I'm sure the rails will drop a bit under load, the 70V is what I get straight from the PSU with nothing connected...

Getting everythng in the case looked so easy at first, but its a nightmare... I'm pretty worried about my ground stars etc...as I was a bit ambitious in adding features, but I will cross that bridge when i get there...
 
hello all,thanks for your unremitting tryout🙂
I am going to arrange a customize kit now,it will include all hard to buy parts.
I have do a remodify of the old board,still no idea if go with GeWa or mine.when the new board will available soon and will be combo offered with the kit.
thanks again,
Zang
 
Oh the frustration!

The 6.3V heater lines only give 3.8V when I actualy have the tube in there... this also causes the relay not to switch the amp part on...

If I pull out the tube the pins measure 6.3V and the relay swithces...

It is powered by a 7.2VAC 1.5VA transformer... only other things on the thransformer is 2 leds, the NE555 and a 5V relay.

Apart from this I should be done.

Need help... close to tears now. 😕
 
Nordic said:
Oh the frustration!

The 6.3V heater lines only give 3.8V when I actualy have the tube in there... this also causes the relay not to switch the amp part on...

If I pull out the tube the pins measure 6.3V and the relay swithces...

It is powered by a 7.2VAC 1.5VA transformer... only other things on the thransformer is 2 leds, the NE555 and a 5V relay.

Apart from this I should be done.

Need help... close to tears now. 😕

Your trafo is way too small. 1.5 VA is close to nothing.... especially if you want to regulate.
You'd better use at least a >10VA trafo (the filament asks for about 300-350mA, plus you have the regulation losses and the relay consumption).

Cheers

Andrea
 
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