"Keith G" wrote in message
...
Apologies for the delay for this 'joint reply' - interrupted by a little
post-prandial 'digestif' by way of a spot of Delius and VW (Larka Sending
and Symphony No. 6 - still playing! :-)

*Massive thanks* to *all* who responded and were, between you, just about
right on the money, from what I can see of it!! (Fekkin' valvies - too
damn sad/skint to be out on the ****/tiles/razzle on a Saturday Night!!
:-)

(I dunno!!)

OK. First up, the valves read as follows (Test voltage, amp on /
Resistance, amp off - the DVM wuz under me bed!!)

V1 = 0.317 V / 10.2 ohms (10R2 ??)

V2 = 0.303 V / 10.0

V3 = 0.322 V / 10.2

V4 = 0.318 V / 10.5

(I'll check tomorrow, but I thought the voltage readings were all "+"
???)

Next, the valve labels are all as follows:

http://www.apah69.dsl.pipex.com/keit.../valvebase.jpg

Now, call me a bluff old cove, but this looks to me a bit like we want
is -37 VDC on the grid (am I right?) - ie. the 'test' voltage?? If so the
valves are all(consistently) 'underbiased?

What do each of these figures mean? (I understand about the valves being
'matched' but I thought was mA / V or summat??)

Many thanks, once again.





Hi Keith,

I'm just wondering if they supply the amplifier with brand new but tested
valves i.e. not burnt in for say 10 hours to allow anode current to
stabilise. If this is the case they may supply the amplifier underbiased
with instructions (if you had them!!) to run it for a while then increase
the bias point to the correct anode current when all the output tube anode
currents are stable (i.e. the bias reading at test points are finally static
and settled down) Just a thought - I'd still get back to the supplier.

Cheers

Mike

"Mike Gilmour" wrote in message
...

"Keith G" wrote in message
...
Apologies for the delay for this 'joint reply' - interrupted by a little
post-prandial 'digestif' by way of a spot of Delius and VW (Larka Sending
and Symphony No. 6 - still playing! :-)

*Massive thanks* to *all* who responded and were, between you, just about
right on the money, from what I can see of it!! (Fekkin' valvies - too
damn sad/skint to be out on the ****/tiles/razzle on a Saturday Night!!
:-)

(I dunno!!)

OK. First up, the valves read as follows (Test voltage, amp on /
Resistance, amp off - the DVM wuz under me bed!!)

V1 = 0.317 V / 10.2 ohms (10R2 ??)

V2 = 0.303 V / 10.0

V3 = 0.322 V / 10.2

V4 = 0.318 V / 10.5

(I'll check tomorrow, but I thought the voltage readings were all "+"
???)

Next, the valve labels are all as follows:

http://www.apah69.dsl.pipex.com/keit.../valvebase.jpg

Now, call me a bluff old cove, but this looks to me a bit like we want
is -37 VDC on the grid (am I right?) - ie. the 'test' voltage?? If so
the valves are all(consistently) 'underbiased?

What do each of these figures mean? (I understand about the valves being
'matched' but I thought was mA / V or summat??)

Many thanks, once again.





Hi Keith,

I'm just wondering if they supply the amplifier with brand new but tested
valves i.e. not burnt in for say 10 hours to allow anode current to
stabilise. If this is the case they may supply the amplifier underbiased
with instructions (if you had them!!) to run it for a while then increase
the bias point to the correct anode current when all the output tube anode
currents are stable (i.e. the bias reading at test points are finally
static and settled down) Just a thought - I'd still get back to the
supplier.

Cheers

Mike
Another thought, if the cathode resistor is 10 ohms then the output valves
are under running by about half (I guess...not gospel) so you should be able
to get an idea by the envelope temperature of the valves i.e. are they
running less hot than you'd nornally expect?

I know VTL amp output valves generally run cool cos de man sez keeps dem
electrons under restraint :-) i.e. instead of 60 or 70mA they run at 45mA
or so and a lot cooler and last longer - he says they sound better...I don't
agree but hey it's a free world (but they sure last looooooonger)

Cool,

Mike

"Mike Gilmour" wrote

I'm just wondering if they supply the amplifier with brand new but tested
valves i.e. not burnt in for say 10 hours to allow anode current to
stabilise. If this is the case they may supply the amplifier underbiased
with instructions (if you had them!!) to run it for a while then increase
the bias point to the correct anode current when all the output tube anode
currents are stable (i.e. the bias reading at test points are finally
static and settled down) Just a thought - I'd still get back to the
supplier.


Not a bad idea - I can struggle through a bit of 'written' German (it's been
a while) but I'm wishin' and hopin' that the seller (Proelektra.de) will be
able to put me onto the designer. I don't think the seller will know and his
English is not too good (better than my German by a long chalk....).

I'll wait for the second amp to turn up (Mon/Tue with any luck) and give the
single sheet of instructions another go (this one's up in the loft, in the
box).