bss epc 740/780

Also i have a user manual pdf somewhere, when i find it i'll post it.

Hi,
I just bought a Turbosound Flashlight system with 5 amps (2 EPC760 & 3 EPC780)

I've been looking for the amplifiers manual on the web for several days.
Unfortunately, the link you posted above is out... Can you post an other link to download it ?

thanks !!!!!

james folkes wrote: the electrical power converter series of amplifiers were, at the time of making, some of the most ambitious pa amplifiers ever built. packed with innovative technology, there is an awful lot of stuff crammed into those 2u chassis, they do indeed weigh a ton too. there aren't that many people who even know how, let alone enjoy repairing them, but i totally lust after them nevertheless. i wanted to get a pile for the martin modular rig from brit row, but they'd all gone before i got the cash together. by modern standards they aren't insanely powerful, a bit over 1k a side into four ohms for the 780, but the spec is absolutely off the charts compared to almost anything you can buy today (like damping factor >1800), they control cones very well. at lower power levels they operate at pure class a topology, but then gets to class a-b as it gets above 20 something watts a side. as suitable for the studio as they are for the stage, they even come with a fan defeat switch to keep them hush-hush, no worries about overheating though as they have excellent protection circuits and you can keep an eye on the temperature with handy gauges on the front. behind the electrostatically charged dust filters you'll find little switches that configure the protection systems for 4 or 2 ohm usage. when they were released a hi-fi magazine tried some out to see if the claim that a pa amp was suitable for the studio could possibly be justified, the verdict was: sell everything else, buy bss epc! the manual is available from the bss website, it makes great reading. well, i think it makes great reading, but then again i do read operating manuals as a leisure activity. james.

looks like someone has been stealing your words James!!

http://www.ebay.co.uk/itm/BSS-epc780-amplifier-4-2-ohms-/330921325379

sorry for the bump, been shopping for one to play with....


Edited by mk2_ginger_biscuit69 - 28 September 2013 at 9:41pm

very nice kit run in class AB with a higher than usual bias so that they run in Class A mode for significantly more than the usual class B such as Labgruppen and others

Cannot remember now if it was fixed high bias or a sliding bias that was used. The other thing that is very different about these is the output stages most amps use a lesser amount of high wattage devices BSS turned it on it head and used lots of lower power devices this amongst other things has the benefit of reducing output impedance of said stage so improving Damping factor which is largely a product of the ratio of load impedance to output stage impedance as it contained lots of devices which in parallel exhibit a much lower value

it does have the disadvantage of giving you more of said devices to drive with there increased Gate capacitance but not difficult to address this issue though many other MOSFET it is a common
 issue not to address this at all the list for this is pretty endless  but C-Audio and many of that type are the culprits using Pseudo "class A" drive circuits to drive them so that cheaper transistors can be used and reliability increased but to the detriment of performance

Sadly very few audio designers fully grasped the principles of MOSFET use for high power Audio Amps but BSS and of course Adyton used them to good effect though the latter used them in a hybrid output stage (Bi-MOS)
so now we are mostly back to Bipolar devices as the impetus for MOSFET development was not continued for audio but they do many other tasks such as control the Motors on your Tube Train and many other power control tasks many SMPS contain MOSFET switching devices or it#s brother the IGBT such as QSC

perhaps i will have look at the service files think still have some on file at the old workshop jog my memories
but all in all super kit often ponder buying some for my collection of old amps coz they really were a wonderful ground breaking design

the amp was very innovative for the time. massively expensive to build - profit margin was almost zero for bss to build. if the amp is modified to latest spec these offer very high audio performance.. on going servicing is certainly an issue because of the skills and parts required.

Dave FFA wrote: the amp was very innovative for the time. massively expensive to build - profit margin was almost zero for bss to build. if the amp is modified to latest spec these offer very high audio performance.. on going servicing is certainly an issue because of the skills and parts required.

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Damn it Dave please STOP!!! You will have me searching for the Damn things relentlessly every waking moment! I must spend my time more wisely Like learning to Lay Bricks Apparently

Agreed definitely a "Loss Leader" for them but really think they were trying to capture a market that was very lucrative but alas eluded them

Damn it again Dave too late!!!....Does anyone know of any BSS EPC's up for grabs anything considered even broken, Sick or thoroughly abandoned in a Warehouse Corner somewhere feeling lost and rejected??? Well here at EPC Care we never put a unloved Amp down Your £3 a month will ensure that they have a happier life once again powering stacks of speakers or Flown Arrays they will even Write to you and you will receive a special soft toy and a wallchart when You join Justcall this Premium rate number Operators are waiting to take your call

LMFAOH time for Tea methinks nice one Dave


Edited by SMP - 07 October 2013 at 1:10pm