BeePre Build Complete - Questions.

[Chris65]

Hi,
Just finished my BeePre build. All resistances were within spec.
Voltages were exact or within 2-3% except C3/Kreg at 5.1Vdc (spec is 3.5-4.5Vdc). D3 was 4.1Vdc. Swapped the stock EL84's over & the higher voltage changed sides.
Then tried a new pair of EL84's (Gold Lion) & got 4.6Vdc both sides.

Also one of the LEDs on the C4S board glows but nothing like as bright as the other 7 LED on the boards.

Any issues with these? Not had a chance to put it into the system to listen yet, will do that tomorrow.

Btw, measured filament current across the .62ohm resistor & get 1.19A 'A' side & 1.18A on the 'B' side.

Thanks.

 

[Paul Birkeland]

All those voltages look good.

The C3/D3 voltage isn't particularly critical, as long as you see more than 3V. 

Which LED isn't glowing as brightly?  If the voltages are all correct coming from the C4S board, this may not be anything you need to worry about.

-PB

 

[Chris65]

Thanks Paul.

The less bright LED is on the A side C4S board, 'B' side of the board, position D2 next to Bb.
C4S voltages on that side:
T2  OL        (OL)
T6  145kΩ  (more than 30kΩ)
T9  0Ω        (0Ω)
T10  rises above 20kΩ

So all correct. Be nice to get it glowing the same, are there any joints I could touch up that might help.

 

[Paully]

How does it sound?

 

[Paul Birkeland]

Thanks Paul.

The less bright LED is on the A side C4S board, 'B' side of the board, position D2 next to Bb.
C4S voltages on that side:
T2  OL        (OL)
T6  145kΩ  (more than 30kΩ)
T9  0Ω        (0Ω)
T10  rises above 20kΩ

Those are resistances.

-PB

 

[Chris65]

Ooops, sorry...try again:

T2    100.8V  (90-110V)
T6    145.8V  (146V)
T9    0V        (0V)
T10  181.2V  (186V)

Other side is virtually the same. 230V area btw.
Anyway, plugged it into the system & been playing Lp's all day, sounds great Paully.

My first experience with 300B's, boy they do ring a bit! With no signal & turning the BeeQuiet switches it chimes quite nicely (& I've removed the springs from one side of the switches). No problem with music playing.

 

[Paul Birkeland]

I wouldn't sweat the LED differences, your voltages are about as spot on as they could be.  (100V is the design center for the 300B plate, and you're right there)

-PB

 

[Chris65]

Yeah thanks, I'm thinking the same now - if it ain't broke....

Next question ;D - put in 6A3's (2 pairs) & get 5.9V 6.2V on the filament one pair, 6.2V & 6.5V on the other, plates vary between 94V & 117V. Any problem with those voltages. Tubes are a mixture of NOS & used.

One pair work ok as I'm listening to them now.

 

[Paul Birkeland]

The 6.2/6.5 is great!

5.9V is 7% off, not too bad either. 

If 117V on the plate doesn't go with the 5.9V tube, I would be wondering how dead that particular specimen was.

-PB

 

[Chris65]

Of course I didn't note which measurements related to which particular tube! 
I'll check more carefully again. Just to confirm that I'm measuring the plate voltage correctly - T2/T17 to ground?

A couple of photos (custom base in progress):

 

[Paul Birkeland]

Of course I didn't note which measurements related to which particular tube! 
I'll check more carefully again. Just to confirm that I'm measuring the plate voltage correctly - T2/T17 to ground?

Man, that's a clean build!

I think of the 300B plate voltage as being OB on each of the big C4S boards, or the end of each 10uF cap closest to the edge of the chassis.  I've only built 3 or 4 BeePres, so the terminal numbers aren't quite etched into my brain.

 

[Grainger49]

That looks very neat.  I am a fan of flying arcs for the signal wires.  Not that I think a 90 degree turn is hard on the signal, it just makes sense to me.