interesting statement from a famous tube amp fanatic, but please dont ask me who
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Having owned a goodly number of valved machines over the years—and continuing to own select specimens for ongoing reference and reminders—my subjective yard stick is simply how much and for pleasure I listen to either the FirstWatt F5 or J2 versus any of my glow worms. If this were a serious tournament rather than one man's preference, none of my current valve amps (all of which are best-case scenarios after years of exploring the breed) even make it into my semi finals now.
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Having owned a goodly number of valved machines over the years—and continuing to own select specimens for ongoing reference and reminders—my subjective yard stick is simply how much and for pleasure I listen to either the FirstWatt F5 or J2 versus any of my glow worms. If this were a serious tournament rather than one man's preference, none of my current valve amps (all of which are best-case scenarios after years of exploring the breed) even make it into my semi finals now.
IR sold some of it's older product lines about 4-5 years ago, including the 240/9240 products, to Vishay. I am unsure weather the exact processing equipment, facilities etc. was included in that deal but the process is the same. The IR marked parts should be dissappearing from the market. Since Vishay owns the rights to these products they could possibly change somewhat also.
Srajan elaborates more on this in M2 article. High priase for F5. I don't disagree with him.
6moons audio reviews: FirstWatt M2
Tintinambulation. I want an amp with tintinambulation.
Shouldn't be hard to achieve:
Tintinnabulation - Definition and More from the Free Merriam-Webster Dictionary
Cleverer people than I,
I have read, I think, that the F5 is very sensitive to speaker short-circuiting, and that this should be avoided at all cost. Is, therefore, fitting Neutrik Speakon terminals to the rear of the amp, speakers and cables, instead of the usual 4mm banana plugs and sockets a good idea? It would mean my kids would have to try very much harder to blow the thing up
Also, Salas, how does the DCB1 mate with the F5? I ask because I read that there could be issues connecting the DCB1 to an amp without an input cap, and the F5 is such a beast...
Many thanks
I have read, I think, that the F5 is very sensitive to speaker short-circuiting, and that this should be avoided at all cost. Is, therefore, fitting Neutrik Speakon terminals to the rear of the amp, speakers and cables, instead of the usual 4mm banana plugs and sockets a good idea? It would mean my kids would have to try very much harder to blow the thing up
Also, Salas, how does the DCB1 mate with the F5? I ask because I read that there could be issues connecting the DCB1 to an amp without an input cap, and the F5 is such a beast...
Many thanks
NP could comment on speaker shorting... however, while not playing any music, it should make no difference...
While playing music, you have a certain amount of time before the Mosfet's internal wire become "fuse wire" and the silicon junctions exceed their current capabilities long enough to self destroy...
I've seen this done 3x with my very much larger and higher power Symphony No.1 Amps - the result is/was the destruction (by internal arc welding that blew a hole through the case of the Hitachi metal cased 2SJ & 2SKs...) of a few of the paralleled mosfets... in the F5 there are either one or two of each flavor, so they'd likely fry...
Fwiw, my amp kept playing at a normal volume even though there was a genuine short (two lugs touching on the back of the amp) - which is fairly amazing... I smelled something getting "hot" in the room first...
I'd not use banana plugs - Binding posts and spade lugs I think are preferable... maybe a cover if kids are an issue... I am suspicious of the Neutrik Speakons for "regular" audiophile use. Otoh, they might be fine...
geez... what did I just say...??
_-_-bear
While playing music, you have a certain amount of time before the Mosfet's internal wire become "fuse wire" and the silicon junctions exceed their current capabilities long enough to self destroy...
I've seen this done 3x with my very much larger and higher power Symphony No.1 Amps - the result is/was the destruction (by internal arc welding that blew a hole through the case of the Hitachi metal cased 2SJ & 2SKs...) of a few of the paralleled mosfets... in the F5 there are either one or two of each flavor, so they'd likely fry...
Fwiw, my amp kept playing at a normal volume even though there was a genuine short (two lugs touching on the back of the amp) - which is fairly amazing... I smelled something getting "hot" in the room first...
I'd not use banana plugs - Binding posts and spade lugs I think are preferable... maybe a cover if kids are an issue... I am suspicious of the Neutrik Speakons for "regular" audiophile use. Otoh, they might be fine...
geez... what did I just say...??
_-_-bear
Here the promised picture from the inside of the F5 amp in the old Hafler enclosure:
Sorry: China pcb's...
In the meantime, I cannibalized one of the burned out Telewatt SA-600 amplifiers.
This parts are very suitable to build an F5:
This amp was really dirty, probably installed in a kitchen area. So I simply put all parts in the dishwasher.
Franz
An externally hosted image should be here but it was not working when we last tested it.
Sorry: China pcb's...
In the meantime, I cannibalized one of the burned out Telewatt SA-600 amplifiers.
This parts are very suitable to build an F5:
An externally hosted image should be here but it was not working when we last tested it.
This amp was really dirty, probably installed in a kitchen area. So I simply put all parts in the dishwasher.
Franz
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Your supply voltage is too low, you'll need some spare change on the rails to reach 5W and some extra for it to sound any good.
Same deal for the JFETs, they do not appreciate such a low drain voltage.
(10.6V rail minus 3.8V at gates of output devices is +/-6.8V at drain of JFETs)
Same deal for the JFETs, they do not appreciate such a low drain voltage.
(10.6V rail minus 3.8V at gates of output devices is +/-6.8V at drain of JFETs)
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I think you should assume about 3 volts more supply than
your peak output voltage. For a 5 watt amp, your peak is
about 9 V, so +/-12 volt rails should about do it.
All these gain devices get pretty nonlinear as the Vds gets low,
so it's always good to put some voltage margin on them. 3V
is the absolute minimum.
your peak output voltage. For a 5 watt amp, your peak is
about 9 V, so +/-12 volt rails should about do it.
All these gain devices get pretty nonlinear as the Vds gets low,
so it's always good to put some voltage margin on them. 3V
is the absolute minimum.