f5-excluding the thyristors-TH1&TH2-redux
thanks PD
as always your input is greatly appreciated-
great suggestion on the thermal isolation pads-really like them!
rob
thanks PD
as always your input is greatly appreciated-
great suggestion on the thermal isolation pads-really like them!
rob
I do not know if technically and audibly it makes much difference but in my set up R13 and R14 are 100 ohms as i did not have any 47's at the time.
The sound is entirely smooth and refined no edginess or sharpness whatsoever. CF the gainclone -IMO the F5's tonality is spot-on-real. There is this wonderful decay to all notes, which is hard to describe, but the slightly longer lingering of each note seems to add a lot of tonal shadings which simply gives vocals and instruments a fuller tone, air and body more akin to what we hear in real life. I am mightily impressed by this 'tubiness'. The gainclone does capture some of this but the preamp is vital IMO here. A valve amp seems to suit it best. With an LDR it can sound sharper and more tonally threadbare,although dynamically it has far more drive with my speakers than the F5.
The sound is entirely smooth and refined no edginess or sharpness whatsoever. CF the gainclone -IMO the F5's tonality is spot-on-real. There is this wonderful decay to all notes, which is hard to describe, but the slightly longer lingering of each note seems to add a lot of tonal shadings which simply gives vocals and instruments a fuller tone, air and body more akin to what we hear in real life. I am mightily impressed by this 'tubiness'. The gainclone does capture some of this but the preamp is vital IMO here. A valve amp seems to suit it best. With an LDR it can sound sharper and more tonally threadbare,although dynamically it has far more drive with my speakers than the F5.
audiojoy's mod on r13&r14
looks like you are dropping signal voltage going into the mosfets-
making the driver transistors work harder for a given volume-
someone who understands this circuit better than I wish to weigh in?
I got a bit of a more "rounded" tone with NP's suggestion of doubling the feedback resistance see post above
rob
looks like you are dropping signal voltage going into the mosfets-
making the driver transistors work harder for a given volume-
someone who understands this circuit better than I wish to weigh in?
I got a bit of a more "rounded" tone with NP's suggestion of doubling the feedback resistance see post above
rob
Hi peter,
In the burning amp, 4 diode bridge is used (with centre tap transformer). In the F5 manual and also your PS diagram, 2 full wave bridge diodes are used. Can I know what is the difference? is it 8 diodes will give better regulation?
In the burning amp, 4 diode bridge is used (with centre tap transformer). In the F5 manual and also your PS diagram, 2 full wave bridge diodes are used. Can I know what is the difference? is it 8 diodes will give better regulation?
Re: f5-feedback mods per NP
It must be me, but can you give a link as I can't find it... Thanks
rob lenk said:
It must be me, but can you give a link as I can't find it... Thanks
f5 feedback mod citation
take a look at post 3731 on the Pass Lab/F5 area of this forum
sorry for the confusion
good am
rob
take a look at post 3731 on the Pass Lab/F5 area of this forum
sorry for the confusion
good am
rob
ccschua said:
See this post for some info: http://www.diyaudio.com/forums/showthread.php?postid=331061#post331061
Hi Peter,
The F5 board is received totaly 4 boards. thks.
This is really eye openner. I need to order the tranny with dual secondary. I will go for this 250VA with 18-0 and 18-0 output.
Is 2 bridges of 4xMUR 860 good for the job?
The F5 board is received totaly 4 boards. thks.
This is really eye openner. I need to order the tranny with dual secondary. I will go for this 250VA with 18-0 and 18-0 output.
Is 2 bridges of 4xMUR 860 good for the job?
Lesson Learnt
When I moved the f5 to the larger system the Gainclone shined via the valve preamp and the F5 sounded awful and flat. Teach me a lesson to mess around with such a carefully designed circuit. I replaced the 100 ohm R13 and 14 to 44 ohms, and it came back to full life! Was unnoticeable initially on the tiny monitor speakers!!
When I moved the f5 to the larger system the Gainclone shined via the valve preamp and the F5 sounded awful and flat. Teach me a lesson to mess around with such a carefully designed circuit. I replaced the 100 ohm R13 and 14 to 44 ohms, and it came back to full life! Was unnoticeable initially on the tiny monitor speakers!!
Received F5 boards
Received the boards. Thanks very much. Now to source some adequate heat sinks.
Timothy
Received the boards. Thanks very much. Now to source some adequate heat sinks.
Timothy
Where are you folks sourcing parts for the F5's, it seems half of the parts are on back order or obsolete, anyone have any suggestions? Mouser and Digikey have most of the parts combined but it seems the issue is these parts...
2SJ74-BL - Obsolete
MUR3060WT - Obsolete
2SK170BLF - B/O
FQA12P20 - B/O
FQA19N20C -B/O
and a few others. Naturally I'd like to get these boards stuffed with good quality parts and have them ready for PS and Chassis by early to mid summer. But as time restraints hold most of us back I'd like the parts here when the time becomes available. Anyone in the Toronto area looking for F5 parts also? I'd be willing to buy local if anyone has the BOM for two stereo amps including PS caps if you have them. PM or mail me if you have it available.... Take care.
2SJ74-BL - Obsolete
MUR3060WT - Obsolete
2SK170BLF - B/O
FQA12P20 - B/O
FQA19N20C -B/O
and a few others. Naturally I'd like to get these boards stuffed with good quality parts and have them ready for PS and Chassis by early to mid summer. But as time restraints hold most of us back I'd like the parts here when the time becomes available. Anyone in the Toronto area looking for F5 parts also? I'd be willing to buy local if anyone has the BOM for two stereo amps including PS caps if you have them. PM or mail me if you have it available.... Take care.
Now your just teasing me with those Rectifier boards Peter LOL, still no intrest in making a small run of PS/Rect boards? It seems you would have 0 issues getting rid of them. You my friend are a bloody tease 
LOL..... 😀
Peace and take care.
LOL..... 😀 Peace and take care.
Peter Daniel said:
user member here jackinnj sells the parts you need as a kit - I think its tech-diy.com IIRC.
Fran
Fran
speakrsrfun said:
I actually run out of F5 amp boards, and since there is still demand for those I will order PS boards as well.
Will also get just the rectifier section and those will be available free of charge: http://www.diyaudio.com/forums/attachment.php?s=&postid=1843189&stamp=1243872132
Peter - Yehaw thats the best news I've heard today, order them up Peter, I'm in for a pair for two stereo F5's. Let me know when they arrive and I'll swing by to pick them up.
Woodturner-fan - I'll give him a PM, and see what the price turns out like, thanks for the heads up...
Peace Y'all.
Woodturner-fan - I'll give him a PM, and see what the price turns out like, thanks for the heads up...
Peace Y'all.
I finally figured out the way to deal with 2 types of PS boards and make the rectifiers boards available for free, including shipping (subject only to forum donation)
Here's the All In One Power Supply board and I will try to stock them permanently.
The tiny rectifier boards on the right brake off and can be used as spares by anybody who does not want the complete PS board. That would include me, as I always prefer to wire caps p2p 😉
If someone needs PS for F4 or F5 amps, I will break off the top section, which creates symmetrical PS (+/-V).
For those who want PS for F1, F2 or F3 amps, I will break off the bottom section which makes it a dual positive supply (2x +V).
The whole board is approx 5.5 x 5.2", which is still very reasonable size.
Of course it is also suitable for use with all 3pin regulators, in line stages.
Here's the All In One Power Supply board and I will try to stock them permanently.
The tiny rectifier boards on the right brake off and can be used as spares by anybody who does not want the complete PS board. That would include me, as I always prefer to wire caps p2p 😉
If someone needs PS for F4 or F5 amps, I will break off the top section, which creates symmetrical PS (+/-V).
For those who want PS for F1, F2 or F3 amps, I will break off the bottom section which makes it a dual positive supply (2x +V).
The whole board is approx 5.5 x 5.2", which is still very reasonable size.
Of course it is also suitable for use with all 3pin regulators, in line stages.
Attachments
Good news Peter, and looks great but doesn't this design limit you to large can type caps unless you want to wire caps off board? I may be a relative layman compared to you but most of the F series and FW amps PS’s have the ability to use multiple caps to achieve a higher capacitance rating on board. Other than the obvious of working off board and just running jumpers from the caps to the relative places on the PS board what is the benefit to using a board of your style? Just curious Peter is all? I’m just worried that I’m going to have a hard time finding Caps with high enough rating cheap enough for me to use as F5 supply caps. Unless you have some laying around your willing to sell…. Anyhow I look forward to the final deign and the prospect of getting my F5’s up and running, Peace and take care.
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