Well, don't know about you lot, but I've spent the day sorting out my valve
gear before Little Santa takes all the 'homeless' (no boxes) munchkins off
for their Xmas holdays - see

http://www.apah69.dsl.pipex.com/keit...w/holidays.jpg

Having painstakingly assembled the requisite Mullies, Svets and JJs
(including a quad of EL34s that I have no use for*) from Jim Fish of Wilson
Valves -

http://www.flashbacksales.co.uk/wils...es/wvindex.htm

(utterly recommended) and some very nice little Mazdas from ebay, I have
'Mullied out' my EARs and they are now on top song. (They drive my Dynaco Mk
IIIs and the sound makes me wonder what the Yanks have been up to for the
last 30+ years!!)

Next, I Mazda'd, Mullied and JJ'd my little AI 400 and it is now fighting
well above its weight - at 12 or 15 wpc (no idea which) you could be
forgiven for thinking it was an 85-100 wpc SS jobbie, I promise you! ;-)

Then it was time to take a look at Johnny WAD. (This little bleeder's been
munching glass lately!)

First up, rip his guts out all over the dining table (note the ****ty
table - Swim wanted to buy one of they flash Eytie tables from JL last year,
I said 'forget it, moi sweet'!) see

http://www.apah69.dsl.pipex.com/keit.../the%20job.JPG

T'werent hard to find the casualties - R6 and R32, see

http://www.apah69.dsl.pipex.com/keith_g/show/burn1.JPG

and http://www.apah69.dsl.pipex.com/keith_g/show/burn2.JPG

Swapped 'em out (by some miracle I had just the right two resistors spare
and no others!), slapped it back together and fired it up.

Ha bloody ha! Within a minute one of the 6550Cs (ain't paying daft money for
KT88s if all they are going to do is tear my board up!) is glowing red up
the middle. At this stage my thoughts are along the lines of 'far king
valves, who in his right mind would bother with 'em?' Get the bottom off
again and whaddaya know? - One of the (coupling?) caps C11 is slightly
bellied! (Anyone with even half a clue about this sort of stuff would have
checked them all a damn sight more careful than I did!)

So it's the board out this time and, courtesy of a ciggie packet....

(see http://www.apah69.dsl.pipex.com/keit...w/ciggies1.jpg)

.....I didn't have to break any connections. Swapped the cap - one of three I
had as spares (my total remaining spares, I might add!) and reassembled it
certain in the knowledge I had fixed it now. (How did I know that? - Easy,
by now I had burnt myself with the fekkin' soldering iron! Always a good
sign! :-)

Been on an hour now - after a few minutes to let it settle, I swapped the
rest of the minis for my last two precious Mullies (CV4003s) and it's
sounding better than ever. (And that ain't ****e, believe you me! ;-)
Ironic ain't it? - The cost of the spares is 1 x 25p and 2 x 14p........!!!

While I'm on, here's a picture of the board

http://www.apah69.dsl.pipex.com/keith_g/show/board.JPG

to give you an idea of how bloody fiddly it is and, finally, a close-up of
my soldering which I don't think is too bad for a clueless **** like me who
doesn't get to do nearly enough of it!

http://www.apah69.dsl.pipex.com/keit.../soldering.JPG

Why am I posting all this guff? - Well, I've enjoyed the day, the sound I'm
getting from the kit now is entirely superb and I just thought it might be
interesting as well as encourage/put off a few people from trying The Wonder
Of Valve Amplification! :-)


*Four EL34s that I don't need? Looks like I'll have to do summat raucous in
the new year!


Merry Xmas one and all and I hope the New Year is a blinder for everyone
here!

;-)


PS. I'd like a couple of dozen more hits on the uk.rec.audio.* page
http://www.apah69.dsl.pipex.com/ to get us up to the 10K mark in the first
year!

Hiya Keith,

Nice thing about bottle gear, easy to spot the fault and get to. Seeing R6
cooked (screen grid resistor?) why did it get mucho grid current I'm
thinking? It may be worth keeping an eye on it even if you've swapped out
the tube. But I think possibly that coupling cap was leaky giving +ve to G1
driving plate current hard and screen grid current burning R6 - Good job
Keith you've got the problem all sorted for Crimbo :-)
Cheers,

Mike

"Keith G" wrote in message
...

Well, don't know about you lot, but I've spent the day sorting out my
valve
gear before Little Santa takes all the 'homeless' (no boxes) munchkins off
for their Xmas holdays - see

http://www.apah69.dsl.pipex.com/keit...w/holidays.jpg

Having painstakingly assembled the requisite Mullies, Svets and JJs
(including a quad of EL34s that I have no use for*) from Jim Fish of
Wilson
Valves -

http://www.flashbacksales.co.uk/wils...es/wvindex.htm

(utterly recommended) and some very nice little Mazdas from ebay, I have
'Mullied out' my EARs and they are now on top song. (They drive my Dynaco
Mk
IIIs and the sound makes me wonder what the Yanks have been up to for the
last 30+ years!!)

Next, I Mazda'd, Mullied and JJ'd my little AI 400 and it is now fighting
well above its weight - at 12 or 15 wpc (no idea which) you could be
forgiven for thinking it was an 85-100 wpc SS jobbie, I promise you! ;-)

Then it was time to take a look at Johnny WAD. (This little bleeder's been
munching glass lately!)

First up, rip his guts out all over the dining table (note the ****ty
table - Swim wanted to buy one of they flash Eytie tables from JL last
year,
I said 'forget it, moi sweet'!) see

http://www.apah69.dsl.pipex.com/keit.../the%20job.JPG

T'werent hard to find the casualties - R6 and R32, see

http://www.apah69.dsl.pipex.com/keith_g/show/burn1.JPG

and http://www.apah69.dsl.pipex.com/keith_g/show/burn2.JPG

Swapped 'em out (by some miracle I had just the right two resistors spare
and no others!), slapped it back together and fired it up.

Ha bloody ha! Within a minute one of the 6550Cs (ain't paying daft money
for
KT88s if all they are going to do is tear my board up!) is glowing red up
the middle. At this stage my thoughts are along the lines of 'far king
valves, who in his right mind would bother with 'em?' Get the bottom off
again and whaddaya know? - One of the (coupling?) caps C11 is slightly
bellied! (Anyone with even half a clue about this sort of stuff would have
checked them all a damn sight more careful than I did!)

So it's the board out this time and, courtesy of a ciggie packet....

(see http://www.apah69.dsl.pipex.com/keit...w/ciggies1.jpg)

....I didn't have to break any connections. Swapped the cap - one of three
I
had as spares (my total remaining spares, I might add!) and reassembled it
certain in the knowledge I had fixed it now. (How did I know that? - Easy,
by now I had burnt myself with the fekkin' soldering iron! Always a good
sign! :-)

Been on an hour now - after a few minutes to let it settle, I swapped the
rest of the minis for my last two precious Mullies (CV4003s) and it's
sounding better than ever. (And that ain't ****e, believe you me! ;-)
Ironic ain't it? - The cost of the spares is 1 x 25p and 2 x
14p........!!!

While I'm on, here's a picture of the board

http://www.apah69.dsl.pipex.com/keith_g/show/board.JPG

to give you an idea of how bloody fiddly it is and, finally, a close-up of
my soldering which I don't think is too bad for a clueless **** like me
who
doesn't get to do nearly enough of it!

http://www.apah69.dsl.pipex.com/keit.../soldering.JPG

Why am I posting all this guff? - Well, I've enjoyed the day, the sound
I'm
getting from the kit now is entirely superb and I just thought it might be
interesting as well as encourage/put off a few people from trying The
Wonder
Of Valve Amplification! :-)


*Four EL34s that I don't need? Looks like I'll have to do summat raucous
in
the new year!


Merry Xmas one and all and I hope the New Year is a blinder for everyone
here!

;-)


PS. I'd like a couple of dozen more hits on the uk.rec.audio.* page
http://www.apah69.dsl.pipex.com/ to get us up to the 10K mark in the first
year!

"Mike Gilmour" wrote in message
...
Hiya Keith,

Nice thing about bottle gear, easy to spot the fault and get to. Seeing
R6
cooked (screen grid resistor?) why did it get mucho grid current I'm
thinking? It may be worth keeping an eye on it even if you've swapped out
the tube. But I think possibly that coupling cap was leaky giving +ve to
G1
driving plate current hard and screen grid current burning R6 - Good job
Keith you've got the problem all sorted for Crimbo :-)
Cheers,

Mike



Hi Mike,

Well, fingers crossed, it's been running for 6 hours straight now and no
sign of overheating. (Room's like an oven, of course!)

I'm blaming the Czech KT88s arcing over for the two instances I've had of a
brew-up with this amp in the last two years, but I'm always eager to learn,
if you think there might another likely cause of this problem I would be
very interested to hear it. Personally, I think it's a sussy little bugger
(Kit88) anyway because WAD didn't keep it on the books for long - superb
sound quality but possibly not too stable? (I really ought to get on to the
WAD forum and see what the 'word on the street' is!)

Don't know what anyone else here might think of a KT88/6550C comparison but
it seems the bass is even more thunderous than it was??? (It ain't got the
biggest OPTs in the world but it's never been too 'polite'.....!!)

(Btw, we're on holiday now so might finally get round to that Black Isle
proggie we've got recorded! :-)

Hi Keith,

Reckon you already nailed the problem caused I guess by that failed coupling
cap. Did the cooked resistors burn the pcb at all? - sometimes standing them
off a bit avoids that damage should it happen again. I've also had the
very occasional '88 flashover on Svets that seems to be just down to a rogue
tube, swapping it out has cured it.
KT88 vs 6550, my experience is the '88 are much more musical but ultimately
don't have the same clout. The bass from the 6550 seems more powerful but
not necessarily as sweet..but this varies a hell of a lot from amp to amp so
I guess its just horses for courses in the end - whatever suits your
particular system. I sometimes change from KT90's to 6550's to KT88's just
to enjoy the strengths of each - none is perfect but an orchestral symphony
sounds just great with '88's and Black Sabbath with 90's with the 6550's
serving most other listening.
I've hit your site a couple of times - hows the hit counter doing??

Mike

"Keith G" wrote in message
...

"Mike Gilmour" wrote in message
...
Hiya Keith,

Nice thing about bottle gear, easy to spot the fault and get to. Seeing
R6
cooked (screen grid resistor?) why did it get mucho grid current I'm
thinking? It may be worth keeping an eye on it even if you've swapped
out
the tube. But I think possibly that coupling cap was leaky giving +ve to
G1
driving plate current hard and screen grid current burning R6 - Good
job
Keith you've got the problem all sorted for Crimbo :-)
Cheers,

Mike



Hi Mike,

Well, fingers crossed, it's been running for 6 hours straight now and no
sign of overheating. (Room's like an oven, of course!)

I'm blaming the Czech KT88s arcing over for the two instances I've had of
a
brew-up with this amp in the last two years, but I'm always eager to
learn,
if you think there might another likely cause of this problem I would be
very interested to hear it. Personally, I think it's a sussy little bugger
(Kit88) anyway because WAD didn't keep it on the books for long - superb
sound quality but possibly not too stable? (I really ought to get on to
the
WAD forum and see what the 'word on the street' is!)

Don't know what anyone else here might think of a KT88/6550C comparison
but
it seems the bass is even more thunderous than it was??? (It ain't got the
biggest OPTs in the world but it's never been too 'polite'.....!!)

(Btw, we're on holiday now so might finally get round to that Black Isle
proggie we've got recorded! :-)

"Mike Gilmour" wrote in message
...
Hi Keith,

Reckon you already nailed the problem caused I guess by that failed
coupling
cap. Did the cooked resistors burn the pcb at all?


Just a tad! - See

http://www.apah69.dsl.pipex.com/keith_g/show/burn1.JPG

and

http://www.apah69.dsl.pipex.com/keith_g/show/burn2.JPG

- sometimes standing them
off a bit avoids that damage should it happen again.


Yes, I think I should have stood them off a bit more than I did (others are
stood off by a good cm or so), but it don't help that the 'component side'
of the board is actually the underside in use! (If the tracks do get burned
off in the future, it won't be the first board I've had to augment with a
bit of 'hard wiring' !! :-)


I've also had the
very occasional '88 flashover on Svets that seems to be just down to a
rogue
tube, swapping it out has cured it.


I think I've had 3 or 4 go in the last 2 years with this amp.....


KT88 vs 6550, my experience is the '88 are much more musical but
ultimately
don't have the same clout. The bass from the 6550 seems more powerful but
not necessarily as sweet..


That's exactly what I'm getting! - No less pleasing overall but a bit
'different' to what I've been used to.


but this varies a hell of a lot from amp to amp so
I guess its just horses for courses in the end - whatever suits your
particular system. I sometimes change from KT90's to 6550's to KT88's just
to enjoy the strengths of each - none is perfect but an orchestral
symphony
sounds just great with '88's and Black Sabbath with 90's with the 6550's
serving most other listening.
I've hit your site a couple of times - hows the hit counter doing??


Heh heh! I just checked and was visitor No. 10,000!!! Thanks for your help,
Mike!

:-)

Have you tried the Russian Teflon coupling caps? Cheap and very good - just a
bit big. I just love them. Neutral and very detailed. Talking big, I use motor
run polyprop caps (40uF) in the PSU with a choke CLC. Depends on the real
estate of the amp - not expensive and I'm surprised no commercial amps use
them. Much faster and more detailed. Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Have you tried the Russian Teflon coupling caps? Cheap and very good - just a
bit big. I just love them. Neutral and very detailed. Talking big, I use motor
run polyprop caps (40uF) in the PSU with a choke CLC. Depends on the real
estate of the amp - not expensive and I'm surprised no commercial amps use
them. Much faster and more detailed. Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

"Mike Gilmour" wrote in message
...
Hi Keith,

Reckon you already nailed the problem caused I guess by that failed
coupling
cap. Did the cooked resistors burn the pcb at all?


Just a tad! - See

http://www.apah69.dsl.pipex.com/keith_g/show/burn1.JPG

and

http://www.apah69.dsl.pipex.com/keith_g/show/burn2.JPG

- sometimes standing them
off a bit avoids that damage should it happen again.


Yes, I think I should have stood them off a bit more than I did (others are
stood off by a good cm or so), but it don't help that the 'component side'
of the board is actually the underside in use! (If the tracks do get burned
off in the future, it won't be the first board I've had to augment with a
bit of 'hard wiring' !! :-)


I've also had the
very occasional '88 flashover on Svets that seems to be just down to a
rogue
tube, swapping it out has cured it.


I think I've had 3 or 4 go in the last 2 years with this amp.....


KT88 vs 6550, my experience is the '88 are much more musical but
ultimately
don't have the same clout. The bass from the 6550 seems more powerful but
not necessarily as sweet..


That's exactly what I'm getting! - No less pleasing overall but a bit
'different' to what I've been used to.


but this varies a hell of a lot from amp to amp so
I guess its just horses for courses in the end - whatever suits your
particular system. I sometimes change from KT90's to 6550's to KT88's just
to enjoy the strengths of each - none is perfect but an orchestral
symphony
sounds just great with '88's and Black Sabbath with 90's with the 6550's
serving most other listening.
I've hit your site a couple of times - hows the hit counter doing??


Heh heh! I just checked and was visitor No. 10,000!!! Thanks for your help,
Mike!

:-)

Hi Keith,

Reckon you already nailed the problem caused I guess by that failed coupling
cap. Did the cooked resistors burn the pcb at all? - sometimes standing them
off a bit avoids that damage should it happen again. I've also had the
very occasional '88 flashover on Svets that seems to be just down to a rogue
tube, swapping it out has cured it.
KT88 vs 6550, my experience is the '88 are much more musical but ultimately
don't have the same clout. The bass from the 6550 seems more powerful but
not necessarily as sweet..but this varies a hell of a lot from amp to amp so
I guess its just horses for courses in the end - whatever suits your
particular system. I sometimes change from KT90's to 6550's to KT88's just
to enjoy the strengths of each - none is perfect but an orchestral symphony
sounds just great with '88's and Black Sabbath with 90's with the 6550's
serving most other listening.
I've hit your site a couple of times - hows the hit counter doing??

Mike

"Keith G" wrote in message
...

"Mike Gilmour" wrote in message
...
Hiya Keith,

Nice thing about bottle gear, easy to spot the fault and get to. Seeing
R6
cooked (screen grid resistor?) why did it get mucho grid current I'm
thinking? It may be worth keeping an eye on it even if you've swapped
out
the tube. But I think possibly that coupling cap was leaky giving +ve to
G1
driving plate current hard and screen grid current burning R6 - Good
job
Keith you've got the problem all sorted for Crimbo :-)
Cheers,

Mike



Hi Mike,

Well, fingers crossed, it's been running for 6 hours straight now and no
sign of overheating. (Room's like an oven, of course!)

I'm blaming the Czech KT88s arcing over for the two instances I've had of
a
brew-up with this amp in the last two years, but I'm always eager to
learn,
if you think there might another likely cause of this problem I would be
very interested to hear it. Personally, I think it's a sussy little bugger
(Kit88) anyway because WAD didn't keep it on the books for long - superb
sound quality but possibly not too stable? (I really ought to get on to
the
WAD forum and see what the 'word on the street' is!)

Don't know what anyone else here might think of a KT88/6550C comparison
but
it seems the bass is even more thunderous than it was??? (It ain't got the
biggest OPTs in the world but it's never been too 'polite'.....!!)

(Btw, we're on holiday now so might finally get round to that Black Isle
proggie we've got recorded! :-)

Keith G wrote:



Don't know what anyone else here might think of a KT88/6550C comparison but
it seems the bass is even more thunderous than it was??? (It ain't got the
biggest OPTs in the world but it's never been too 'polite'.....!!)

Have a look at this, it may help

http://www.worldaudiodesign.co.uk/fo...ght=6550+kat88

--
Nick