tube amps

Hey blitzo
The amp has been complete for a year so have not changed any yet
they should last for ten years or so with occaisional bias adjustment being required
they are run at high voltage/low dissapation...best way to run tubes...gives good long term
reliability
the fans help...keeping them within the optimum temperature range for good reliable
operation
the tubes themselves are readilly available and reasonably cheap
average 10 pounds each...and i go for mullard of tunscram uk made used tubes
which are bullet proof...new made are available but tend to be of indifferent quality

I'm just asking because austin from jah observer soundsystem in these days checks all the valve in its amps, and he do that every year before carnival.

Thanks for the reply Ian.

I quite fancy having a go at building a 2 chan valve amp. Prob 100W per side for hifi use. 4 EL34s per side. I am not sure where to source the transformers from. Do you have a trusted suppier or do you have to get them wound for you :

cheers
Daz

www.sowter.co.uk/
These guys have been in the business for a long time and are probably the best available.
livinginthepast-audioweb.co.uk/xfrmrpp.php these guys however are cheaper for a 100w pp o/p transformer.

bitzo wrote: I'm just asking because austin from jah observer soundsystem in these days checks all the valve in its amps, and he do that every year before carnival.

Bitzo have you seen Austin checking each valve with a tester or checking each valve whilst sitting in the amps? Jah Observer is a veteran sound system and sound well heavy. They run a Garrard 401 which has the heaviest bass available from any turntable known to man!!!!!! smiley32

Thanks Narinder.

Just what I was looking for smiley20

Daz

NITZ V1505 wrote: Bitzo have you seen Austin checking each valve with a tester or checking each valve whilst sitting in the amps? Jah Observer is a veteran sound system and sound well heavy. They run a Garrard 401 which has the heaviest bass available from any turntable known to man!!!!!! smiley32

Just talk to him a few times about this issue.

Hey Bitzo
Sure i check my amps prior to playin out...more to do with makin sure that the bias
is still set up accuratly...minimises dc current imbalance in the output tx...minimises crossover distortion
allways do this before a proper session...sure this is what austin is doing
dead tube will pull no current....easy to spot

Daz
For a 100 watt tube amp you can get your transformers off the shelf
do a web search for hammond transformers...US company but they have distibution here
save some money sowter are expensive...hammond perform perfectly
custom built...Bls electronics in Durham....Or John chambers who is doing some wk for
me at pres...

sorry ian, not really in my intention bias anyone's work. Just trying to learn, so thanks for sharing your knowledge smiley20

Hi Ian
Thanks for that. Nice to know that there are a number of supply companies still doing valve stuff.

I have 10 new/old stock Mullard EL34s (so have a couple of spares) and managed to dig out a full set of 8 ceramic sockets/bases so all good. Going to go for a regulated DC heater supply with its own TX/Rect/Reg circuit. Wondering if some form of soft start power supply for the HT would be worth while. Using solid state rectifiers and dont realy want to hit the tubes full on at startup. Any tricks on this : .
Dont laugh too loud but I had thought of using a timer relay and an incandesent lamp in series with the Primary on the HT mains TX. The lamp would limit the current at startup and then be out of circuit/shorted when the timer relay contacts closed. Bit old school and I am sure there is a better way of doing it :lol:

Daz