Recommend tutorial on testing ss parts

**Dave Plowman (News)** · March 8th 07, 11:44 PM posted to uk.rec.audio

In article .com,
Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit? That's a
PNP transistor - the 546 and 549 are NPN. The 546 and 446 are
complimentary pairs.

Typing slip - should read 546, 549 etc. All NPN

Right. Just as well - I'm not sure a 549 exists. ;-)

--
*Money isn't everything, but it sure keeps the kids in touch.

Dave Plowman London SW
To e-mail, change noise into sound.

**Dave Plowman (News)** · March 9th 07, 09:24 AM posted to uk.rec.audio

In article ,
Dave Plowman (News) wrote:
In article .com,
Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit?
That's a PNP transistor - the 546 and 549 are NPN. The 546 and 446
are complimentary pairs.

Typing slip - should read 546, 549 etc. All NPN

Right. Just as well - I'm not sure a 549 exists. ;-)

I mean, of course, 459. It's not in my copy of Towers.

--
*Sorry, I don't date outside my species.

Dave Plowman London SW
To e-mail, change noise into sound.

**Andy Evans** · March 9th 07, 09:52 AM posted to uk.rec.audio

On Mar 9, 10:24ï¿½am, "Dave Plowman (News)"
wrote:
In article ,
* *Dave Plowman (News) wrote:

In article .com,
* *Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit?
That's a PNP transistor - the 546 and 549 are NPN. The 546 and 446
are complimentary pairs.
Typing slip - should read 546, 549 etc. All NPN
Right. Just as well - I'm not sure a 549 exists. ;-)

I mean, of course, 459. It's not in my copy of Towers.

--
*Sorry, I don't date outside my species.

* * Dave Plowman * * * * * * * * London SW
* * * * * * * * * To e-mail, change noise into sound.

Here's another CCS which works - tried it last night. A lot closer to
Don's idea.
http://www.vacuumstate.com/schematics/pp-1c_ps_s.gif

**Don Pearce** · March 9th 07, 10:01 AM posted to uk.rec.audio

On 9 Mar 2007 02:52:51 -0800, "Andy Evans"
wrote:

On Mar 9, 10:24ï¿½am, "Dave Plowman (News)"
wrote:
In article ,
* *Dave Plowman (News) wrote:

In article .com,
* *Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit?
That's a PNP transistor - the 546 and 549 are NPN. The 546 and 446
are complimentary pairs.
Typing slip - should read 546, 549 etc. All NPN
Right. Just as well - I'm not sure a 549 exists. ;-)

I mean, of course, 459. It's not in my copy of Towers.

--
*Sorry, I don't date outside my species.

* * Dave Plowman * * * * * * * * London SW
* * * * * * * * * To e-mail, change noise into sound.

Here's another CCS which works - tried it last night. A lot closer to
Don's idea.
http://www.vacuumstate.com/schematics/pp-1c_ps_s.gif

You're getting there! Next good mod is to replace those triodes with a
couple of nice BJTs....

d

--
Pearce Consulting
http://www.pearce.uk.com

**Andy Evans** · March 9th 07, 03:38 PM posted to uk.rec.audio

On Mar 9, 11:01ï¿½am, (Don Pearce) wrote:
On 9 Mar 2007 02:52:51 -0800, "Andy Evans"

wrote:
On Mar 9, 10:24ï¿½am, "Dave Plowman (News)"
wrote:
In article ,
* *Dave Plowman (News) wrote:

In article .com,
* *Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit?
That's a PNP transistor - the 546 and 549 are NPN. The 546 and 446
are complimentary pairs.
Typing slip - should read 546, 549 etc. All NPN
Right. Just as well - I'm not sure a 549 exists. ;-)

I mean, of course, 459. It's not in my copy of Towers.

--
*Sorry, I don't date outside my species.

* * Dave Plowman * * * * * * * * London SW
* * * * * * * * * To e-mail, change noise into sound.

Here's another CCS which works - tried it last night. A lot closer to
Don's idea.
http://www.vacuumstate.com/schematics/pp-1c_ps_s.gif

You're getting there! Next good mod is to replace those triodes with a
couple of nice BJTs....

Yes - passing quickly over that idea, I've rigged up a test setup for
CCSs and I'm churning them out. Did 16 today. Only tested the first
pair, so I hope the rest are OK. Haven't had a listen yet. the IRF820
is a simpler design and a faster build so hope it sounds good. Andy

**Andy Evans** · March 11th 07, 11:57 AM posted to uk.rec.audio

On Mar 9, 4:38?pm, "Andy Evans" wrote:
On Mar 9, 11:01?am, (Don Pearce) wrote:

On 9 Mar 2007 02:52:51 -0800, "Andy Evans"

wrote:
On Mar 9, 10:24?am, "Dave Plowman (News)"
wrote:
In article ,
? ?Dave Plowman (News) wrote:

In article .com,
? ?Andy Evans wrote:
You've mentioned BC 459 - this is another part of the circuit?
That's a PNP transistor - the 546 and 549 are NPN. The 546 and 446
are complimentary pairs.
Typing slip - should read 546, 549 etc. All NPN
Right. Just as well - I'm not sure a 549 exists. ;-)

I mean, of course, 459. It's not in my copy of Towers.

--
*Sorry, I don't date outside my species.

? ? Dave Plowman ? ? ? ? ? ? ? ? London SW
? ? ? ? ? ? ? ? ? To e-mail, change noise into sound.

Here's another CCS which works - tried it last night. A lot closer to
Don's idea.
http://www.vacuumstate.com/schematics/pp-1c_ps_s.gif

You're getting there! Next good mod is to replace those triodes with a
couple of nice BJTs....

Yes - passing quickly over that idea, I've rigged up a test setup for
CCSs and I'm churning them out. Did 16 today. Only tested the first
pair, so I hope the rest are OK. Haven't had a listen yet. the IRF820
is a simpler design and a faster build so hope it sounds good. Andy- Hide quoted text -

- Show quoted text -

Well, all 16 working - eventually. A few dodgy capacitors from the
depths of drawers (probably up to 20 years old or maybe more) - I
inherited a whole wodge of componants from Beard Audio when it stopped
production and these have been very useful, apart from the fact that
Bill hadn't thrown away a lot of stuff that didn't work. The bin is
there for a purpose!!!