audio-talk

Them laws of physics getting in the way again.

Have a lot to answer for ..

.

Assembly Hint #2

Square pads indicate the cathode ends of diodes (stripe on body).



#

Assembly Hint #1

Just a thought, when you put the resistors on might be advisable to not let their bodies rest directly on top of the top track. Dunno how good the insulation is. P'raps leave a small gap underneath.


#

A-ha! A cunning plan. I'm interested what happens. Yes if the anode Volts drop then so will the cathode Volts, hence the current. In light of what Nick suggests about the valve power dis, might be a good idea to leave that 30k resistor in there and then insert the choke below it twixt that and anode...

= option #3

which I've not actually tried yet


#

Dave the bass wrote:Conclusion, with 6DN7 I don't really need 400H do I? 200H would do really.

Using 6EM7 using 1 200H choke gives a f-3dB of 31.8Hz and 2 chokes gives 15.9Hz.

Hmmmm.

DTB

How about that.

Dave the bass wrote:good lord! We're still on topic!

Nothing is without change ..


#

That, of course, is the ultimate limiting factor

#

Hold on I'm talking about the simple EL84 amp at the mo? With the ECC99 input stages? The TX was quite chunky so probs could be better than 160mA, depends on wire size. That's the trouble with full-wave, the space the wire takes up. IIRC it was: 275-0-275V @ 160mA (it sez on label) 3.15-0-3.15V @ 3A...

Germany though What sort of current for the HT winding? Funnily enough I was down at Danbury this morning and looking at a 275-0-275, with 6.3 + 6.3; 160mA though for the HT IIRC. I was saying do we need to "stock" summat like this cos this kind of thing does come up in queries. But as 5V ...

Priorities, priorities!

Have a nervous breakdown or pick up boards, a quandary indeed


#

Now, when a transformer saturates what does it sound like. Is it 'distorted' or as you say just mush comes out? Yes it's usually like clipping (overload) distortion, one half of the waveform might come out OK but the other will be just a flat line, perhaps steeply sloped. That being the direction i...

Ta Nick, yes forgot to mention the gap thickness can be critical, you have to imagine it's like two electro-magnets with their opposite poles placed together. If the gap is too thin the attraction is too great and the single direction magnetization is too strong, so the bass goes off. Conversely if ...

Because without the gap the magnetic field has an uninterrupted path through the core, and the DC sets up a permanent field in one direction which is quite strong. This leaves very little "headroom" for AC to operate in, hence the core saturates easily, which means it's magentized as far a...

All packets posted, except Phil cos he's going to collect I believe.


#