Jan,
I think CAVU has it pretty much covered.
Cool, sounds good, no mods required...unless it requires repair in which case you might as well improve.
I've made replacement replacement back plates for mine with Powercon/Speakon/RCA connectors and got rid of the bridging circuitry.
In spite of the XLR connectors the amp does not have balanced in - pins 1 and 2 are linked together and to tip of the TS jack.
I had one with failed electrolytic caps and one with a failed dual transistor on the input...
One of mine looks like tracks on the pcb had corroded away and it's been repaired (surprisingly well) in the distant past.
Every Lab amp I've come across in SA has come out of a Cinema. They were driving Fostex equipped cabinets similar to Altec VOTT's and usualy some EV subs.
I use a 600 to drive Tannoy System 15 drivers in custom enclosures in my lounge.
I use a 2 x 300's and a 600 to drive a Tannoy System 15's centre and 2 x System 15 with additional JBL bass driver.
Another 600 runs a pair of double EV 18 - all in the home cinema system...
John
I think CAVU has it pretty much covered.
Cool, sounds good, no mods required...unless it requires repair in which case you might as well improve.
I've made replacement replacement back plates for mine with Powercon/Speakon/RCA connectors and got rid of the bridging circuitry.
In spite of the XLR connectors the amp does not have balanced in - pins 1 and 2 are linked together and to tip of the TS jack.
I had one with failed electrolytic caps and one with a failed dual transistor on the input...
One of mine looks like tracks on the pcb had corroded away and it's been repaired (surprisingly well) in the distant past.
Every Lab amp I've come across in SA has come out of a Cinema. They were driving Fostex equipped cabinets similar to Altec VOTT's and usualy some EV subs.
I use a 600 to drive Tannoy System 15 drivers in custom enclosures in my lounge.
I use a 2 x 300's and a 600 to drive a Tannoy System 15's centre and 2 x System 15 with additional JBL bass driver.
Another 600 runs a pair of double EV 18 - all in the home cinema system...
John
Attachments
A little googling turned up all sorts of info...
From here, the specs are...
A photo:
Manual here:
FOSTEX 300 USER MANUAL Pdf Download.
From here, the specs are...
A photo:
An externally hosted image should be here but it was not working when we last tested it.
Manual here:
FOSTEX 300 USER MANUAL Pdf Download.
Ill love it.I have a Fostex 600 I drive double Electrovoice EVM15B11 with a compression driver, one chanel for the EVM15B11 and the other for the compression driver, I make a comparation with a Crown MA 3600, a QSC RMX 1450 and a Bryston 4B, the Bryston his my first choice but the Fostex his close, more definion then the Crown and QSC, the Fostex have punchy bass and well hi freq definition, I paid under 100.$ Can it's a very good bargain,
Hi Scooby... bringing the old topics alive again 
I dont know what hype is happening currently but it seems to enter the fancy vintage era
I got a a300 for 175$ and a600 for 120$.
Compared them to some class a tubes and parasound 806 and 2200ii.
What impressed me most was the SNR and the stepped attenuators. They’re really highest grade and work flawless despite the age. The SNR is so low, i cant hear the slightest noise putting my ears right into my horns (108dbspl). Absolutely clean.
Also ran them on demanding fullrange electrostatics. They stay absolutely clean till the clipping limit. They don’t even sound stressed or change any of their character shortly before the clipping. Absolutely layed back. Respect!
I must say compared to parasound ( 10 times the price) they may lack a tiny sparkle of HF resolution, attack, and bass. But keep up pretty well to my surprise!!!
Not as warm soft as a tube, more power, but warmer softer than parasound.
All in all rather how i remember the sound of nelsson pass - right in the middle between valves and AB-SS characters.
So, I like the fostex, and the SNR combined with the brilliant potis are a killer feature for high sensitivity speakers. Don’t understand why it makes even less noise than other modern hifiamps which claim even 10dB lower SNR. But i guess that’s part of the japanese decency - often fostex seems to better than their specs tell. Very often.
Cheers
Josh
I dont know what hype is happening currently but it seems to enter the fancy vintage era
I got a a300 for 175$ and a600 for 120$.
Compared them to some class a tubes and parasound 806 and 2200ii.
What impressed me most was the SNR and the stepped attenuators. They’re really highest grade and work flawless despite the age. The SNR is so low, i cant hear the slightest noise putting my ears right into my horns (108dbspl). Absolutely clean.
Also ran them on demanding fullrange electrostatics. They stay absolutely clean till the clipping limit. They don’t even sound stressed or change any of their character shortly before the clipping. Absolutely layed back. Respect!
I must say compared to parasound ( 10 times the price) they may lack a tiny sparkle of HF resolution, attack, and bass. But keep up pretty well to my surprise!!!
Not as warm soft as a tube, more power, but warmer softer than parasound.
All in all rather how i remember the sound of nelsson pass - right in the middle between valves and AB-SS characters.
So, I like the fostex, and the SNR combined with the brilliant potis are a killer feature for high sensitivity speakers. Don’t understand why it makes even less noise than other modern hifiamps which claim even 10dB lower SNR. But i guess that’s part of the japanese decency - often fostex seems to better than their specs tell. Very often.
Cheers
Josh
i have recently been given a 600 .. but it has a quickly developed a fault on the right chan
in the last few days it started to make random scratch noises on the right chan ,, even with no source connected and the volume completely down
then last night the clip ( overload ) light on right chan came on and quite a bit of distortion ensued on that chan ..
any clues,,, i've popped the lid off and i cant see anything obviously blown , no exploded caps ... no burn marks anywhere ... it looks like a really solid build ..
i would very much like to get this working again asap
in the last few days it started to make random scratch noises on the right chan ,, even with no source connected and the volume completely down
then last night the clip ( overload ) light on right chan came on and quite a bit of distortion ensued on that chan ..
any clues,,, i've popped the lid off and i cant see anything obviously blown , no exploded caps ... no burn marks anywhere ... it looks like a really solid build ..
i would very much like to get this working again asap
Well since 2006 when I first asked about these amps, I've had probably 20 of them through my hands! They are great amps and tend to be pretty reliable.
I've recapped, replaced output relays and had the occasional odd little issue.
The clip/overload circuit monitors the points C and D in the attached schematic(and A and B in the other channel). If your problem is only one channel and happens with the attenuator down, the cause is to the left of C and D...
I have had the dual input transistor give trouble before and would probably also change the couple of electrolytics in the area...
Channel 1 schematic has reference voltages to check...
I've recapped, replaced output relays and had the occasional odd little issue.
The clip/overload circuit monitors the points C and D in the attached schematic(and A and B in the other channel). If your problem is only one channel and happens with the attenuator down, the cause is to the left of C and D...
I have had the dual input transistor give trouble before and would probably also change the couple of electrolytics in the area...
Channel 1 schematic has reference voltages to check...
Attachments
thank you for your reply ... sorry its taken so long to get back to you .. i put the amp in my storage lock up and forgot it was there until yesterday ... ive not made any attempt to repair it yet but i will take a look using the schematic you provided for me
do you by chance have the full service manual
if so would it be possible to get a copy of it
Many thanks in advance
do you by chance have the full service manual
if so would it be possible to get a copy of it
Many thanks in advance