well, I cannot Edit my post #20 to complete it, strange...
I believe I will replace the R13 and R14 by the 50 ohms Vishay "Nude" Bulk Foil resistor TX 2352, like I plan to do for the R9.
By the way, P1 and P2 are in // with R3 and R4, so I assume their quality is also important: do you believe there should be a sonic benefit to replace the Bourns by a Vishay 1280G ?
I believe I will replace the R13 and R14 by the 50 ohms Vishay "Nude" Bulk Foil resistor TX 2352, like I plan to do for the R9.
By the way, P1 and P2 are in // with R3 and R4, so I assume their quality is also important: do you believe there should be a sonic benefit to replace the Bourns by a Vishay 1280G ?
Hi,
The vishay 1280g is bulk metal foil (thus the price $$$). As ZM says, don't worry, just make it.
OK thanks, listening sessions will decide.
By the way, as I am about to order the parts for the Power Supply, I have a doubt regarding the value of the very first capacitor directly connected to the AC line: on the F5 P.S diagram it is identified as ".0033 LINE" .
Is it 3.3nF ? (it makes me think about these small disk capacitors ...)
By the way, as I am about to order the parts for the Power Supply, I have a doubt regarding the value of the very first capacitor directly connected to the AC line: on the F5 P.S diagram it is identified as ".0033 LINE" .
Is it 3.3nF ? (it makes me think about these small disk capacitors ...)
notice the line
This cap should never be connected between PE and Neutral nor between PE and Live.
this confirms that the capacitor is rated to be safely connected between Neutral and Live of the mains. X2 also has a maximum voltage rating of ~250Vac. This aloows it to be used on UK mains systems that can reach 254Vac and still be in suppliers allowed tolerance.
This cap should never be connected between PE and Neutral nor between PE and Live.
thanks; as I am a cautious man, I will probably choose one with a higher voltage rating, because in France our normal voltage is 240V so may occasionally exceed 250V... I have a 0.01uF left, it should be OK even if bigger than the 3.3nF...
my English is probably not good enough: what do you mean ? if I correctly understand the Nelson diagram, this cap is connected between the 2 AC cables offering the 230V between them (-not the earth).
By the way I have never used a Thermistor before the main transformer as indicated on the F5 manual:
An externally hosted image should be here but it was not working when we last tested it.
and my main transformer having only one primary (240V only) I do not see how to connect it... Unless there is a interest to do so, I will not use it as I did in my previous projects...
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It's certainly wise to get an X2 3.3nF cap that's rated higher than 250vAC. Farnell in the UK stock only one such part: VISHAY BC COMPONENTS|BFC233820332|CAPACITOR, CLASS X2, 3.3NF, 310VAC | Farnell United Kingdom
I'll send you one when I get my 5 if you haven't found one yet.
Regarding thermistors on transformers, only if the primaries are centre tapped for 2x115v do you need to adjoin the centres with a thermistor to get a single 230v primary (and even then it is not something I've never seen done before, but I have done it since seeing this Pass design, and well, being an actual electronics genius, I trust Papa's work, so surely there must be some advantage to this )
I'll send you one when I get my 5 if you haven't found one yet.
Regarding thermistors on transformers, only if the primaries are centre tapped for 2x115v do you need to adjoin the centres with a thermistor to get a single 230v primary (and even then it is not something I've never seen done before, but I have done it since seeing this Pass design, and well, being an actual electronics genius, I trust Papa's work, so surely there must be some advantage to this
)250Vac X rated and 250Vac Y rated capacitors are designed for use on all 220/240Vac mains supply system that run within the standard tolerances of supply.
As far as I know the UK upper limit of 254Vac (~230Vac+10% or was 240Vac+6%)) is not exceeded by any other country using a nominal 220/230/240Vac supply.
As far as I know the UK upper limit of 254Vac (~230Vac+10% or was 240Vac+6%)) is not exceeded by any other country using a nominal 220/230/240Vac supply.
I'd rather talk about the big part in building an F5 - the one that costs by far the most and is the hardest to source - the case, with heat-sinks. Or alternatively, the heat-sinks around which to build your amp.
I'm considering this:
modushop.biz
It's not cheap by any means, but I haven't found 1. good 2. cheap and 3. easy options for this project so far. Wadya think fellas?
I'm considering this:
modushop.biz
It's not cheap by any means, but I haven't found 1. good 2. cheap and 3. easy options for this project so far. Wadya think fellas?