Steve - Wonderful! If your PSU is good you have a much better chance of a successful project.
(And although that sounds obvious, many people just build the whole amp and fire it up in one go, without testing to see if the PSU is operating properly...)
(And although that sounds obvious, many people just build the whole amp and fire it up in one go, without testing to see if the PSU is operating properly...)
While we're on the subject,
I have 2x30v 750va plitron. According to calculations, that shoud give me +- 40V rails. Is that too high or should I target 32V which gives 2 x 24v?
I have 2x30v 750va plitron. According to calculations, that shoud give me +- 40V rails. Is that too high or should I target 32V which gives 2 x 24v?
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Hi necplusultra
When I chose my transformer simply followed the instructions in the First Watt F5 turbo doc that Mr Pass has kindly shared, link http://www.firstwatt.com/pdf/art_f5_turbo.pdf
My 300va one maybe a little underpowered but I'm not too worried as I have sensitive 95db speakers
When I chose my transformer simply followed the instructions in the First Watt F5 turbo doc that Mr Pass has kindly shared, link http://www.firstwatt.com/pdf/art_f5_turbo.pdf
My 300va one maybe a little underpowered but I'm not too worried as I have sensitive 95db speakers
You will have to cascode the front end. (I.E., the v3)
You will have to use 50v caps.
You will need to watch the total dissipation of the outputs and bias accordingly.
There is nothing insurmountable about it, depending on which version you are planning.
But it's always less headache to buy and use the proper transformer.
You will have to use 50v caps.
You will need to watch the total dissipation of the outputs and bias accordingly.
There is nothing insurmountable about it, depending on which version you are planning.
But it's always less headache to buy and use the proper transformer.
Thanks 6L6
I may try to tweek with your recommendation for 40v configuration somewhat but I'll be safe and buy the reccomended tfo.
I'm using 2 x 18v 300 VA for standard F5 which was implicitly recomended in the F5 article.
Are there any published reccomendations for F5T V1 V2 , V3?
From the F5T article, it states 32 V rails for V1 and V2 but I did not see any mention of V3 reccomendations nor the tfo VA rating.
regards.
I may try to tweek with your recommendation for 40v configuration somewhat but I'll be safe and buy the reccomended tfo.
I'm using 2 x 18v 300 VA for standard F5 which was implicitly recomended in the F5 article.
Are there any published reccomendations for F5T V1 V2 , V3?
From the F5T article, it states 32 V rails for V1 and V2 but I did not see any mention of V3 reccomendations nor the tfo VA rating.
regards.
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The rule of thumb is 6 times the 8-ohm power output of the amplifier equals transformer VA.
For instance, the F5T v2 is 50wpc x2
The whole amp is 100 watt power output.
100 x 6 = 600VA minimum
For instance, the F5T v2 is 50wpc x2
The whole amp is 100 watt power output.
100 x 6 = 600VA minimum
and hence the 300va rating for f5: 6x2x25wpc
thanks 6L6
Learning so much from pass amp building.
thanks 6L6
Learning so much from pass amp building.
I've just spotted this kit on E-Bay, it might help a few prospective builders out.
2 X DELUXE F5 FET & MOSFET CURRENT FEEDBACK AUDIO POWER AMPLIFIER KIT! | eBay
2 X DELUXE F5 FET & MOSFET CURRENT FEEDBACK AUDIO POWER AMPLIFIER KIT! | eBay
Some guys just like to buy kits of parts.... I was only showing what I found.
If you don't want to buy from E-Bay that's your choice.
If you don't want to buy from E-Bay that's your choice.
Hm... Input jfets are interesting. Do you think the are legit? Maybe I am being paranoiac, but there many rumors out there about fake transistors, opamps etc.
Just for the record: I still think that buying a kit or pcb from e-bay not diyaudio store is not fare for the community (not trying to judge here).
Just for the record: I still think that buying a kit or pcb from e-bay not diyaudio store is not fare for the community (not trying to judge here).
I buy from Spencer and Alweit on epay for the small toshiba jfets. I have not had any trouble with them.
Thanks, Tea-Bag, I ordered from Spencer, but the eBay seller from above sells them cheaper, so I was thinking maybe buy more 🙂.
The F5 and other designs from Nelson Pass are his copyright which he shares with the DIY Comunity in a very selfless fashion, along with all the help he provides in this forum. He also allows diyaudio to sell the boards and also People making their Own for personal use.
Any other people making boards for sale are not authorised and are infringing his copyright and intellectual property.
Unfortunately these Asian sellers on ebay have no respect for this and keep profiting from other people's hard work.
It is up to each person to take this into account when building stuff, in my opinion the least would be to support the forum and accept Nelson's simple request.
Originally Posted by KatieandDad
Some guys just like to buy kits of parts.... I was only showing what I found.
If you don't want to buy from E-Bay that's your choice.
If only that were true for Apple,Nike, Samsung,LG, Mattel, and on and on and on ...
Everyone may have already seen this, but here's the link, just in case:
New Year, New Features at Linear Integrated Systems
LSJ74 this year?
New Year, New Features at Linear Integrated Systems
LSJ74 this year?