Hi Acowens -
Thanks for the questions. Keep them coming. I'm not sure how far you are along in your planning. With what you've mentioned so far, quite frankly, I'd recommend the easiest route. Feel free to provide some more information. I just started in DIY earlier in the year, so I feel OK starting off with this recommendation.
1) There is no "complete" parts list. Part of the fun is figuring this out. I promise it won't be too bad, and we'll get you going. You almost definitely will curse having forgot one key part for an order, but it's kind of a right of passage. The good news is that there is an F5 parts kit, a fairly simple PSU you can build with a BoM available, etc. etc. It's not as big a challenge as you might think.
2) There is certainly enough information out there to have a successful build, but it's not like the step-by-step for the ACA. First - Check out the build guide linked from the store site. Firstwatt F5 amplifier v3 - diyAudio Guides
Read this thread and the F5V3 thread along with some other build guides for First Watt amps. There is a ton of information. Do a bunch of reading. Take notes. Then after you've read through a few things decide if you want to take it on. I have every confidence you can do it, but it's not like an ACA. You'll be working with mains voltages, and it's not quite as simple a build.
Have fun taking a look at some threads, and we're here to help.
Thanks for the questions. Keep them coming. I'm not sure how far you are along in your planning. With what you've mentioned so far, quite frankly, I'd recommend the easiest route. Feel free to provide some more information. I just started in DIY earlier in the year, so I feel OK starting off with this recommendation.
1) There is no "complete" parts list. Part of the fun is figuring this out. I promise it won't be too bad, and we'll get you going. You almost definitely will curse having forgot one key part for an order, but it's kind of a right of passage. The good news is that there is an F5 parts kit, a fairly simple PSU you can build with a BoM available, etc. etc. It's not as big a challenge as you might think.
2) There is certainly enough information out there to have a successful build, but it's not like the step-by-step for the ACA. First - Check out the build guide linked from the store site. Firstwatt F5 amplifier v3 - diyAudio Guides
Read this thread and the F5V3 thread along with some other build guides for First Watt amps. There is a ton of information. Do a bunch of reading. Take notes. Then after you've read through a few things decide if you want to take it on. I have every confidence you can do it, but it's not like an ACA. You'll be working with mains voltages, and it's not quite as simple a build.
Have fun taking a look at some threads, and we're here to help.
I have used two/twin transformers on many amp projects without issue. I once read there was/maybe a benefit of 'galvanic isolation' where by one transformer suppling the poss rail and another suppling the neg rail. Not sure if this stacks up but seems feasible. Not that I personally recall a sonic benefit. But Im no expert by any measure..just a budding DIYer.
Google says..
Galvanic isolation is used where two or more electric circuits must communicate, but their grounds may be at different potentials. It is an effective method of breaking ground loops by preventing unwanted current from flowing between two units sharing a ground conductor.
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Most people will be using a toroidal transformer where the secondary windings are wound in parallel, this isn't a problem.
Some EI laminated transformers have the secondary windings side by side or one on top of the other, they are not identical; try the same trick and you will cook your transformer.
Some EI laminated transformers have the secondary windings side by side or one on top of the other, they are not identical; try the same trick and you will cook your transformer.
Hello LAVERDA,
I did the same many times in my poweramps. Never had a problem.
In my F5T I used 2x30 V / 1000W tansformers for one Monoblock.
2 pairs of secondary windings feeding the positive and the negative side of the PSU. I've got +/- 42.4 Volts on the rails ( sure it is with double JFETs and cascoded). And it is running hot!
Greets
Dirk
I did the same many times in my poweramps. Never had a problem.
In my F5T I used 2x30 V / 1000W tansformers for one Monoblock.
2 pairs of secondary windings feeding the positive and the negative side of the PSU. I've got +/- 42.4 Volts on the rails ( sure it is with double JFETs and cascoded). And it is running hot!
Greets
Dirk
F5 kit
Thanks for the advice! After having done some homework reading on the various Pass amp build kits avail here I'm trying to figure out which one makes the most sense for me. I'll probably run a pair of Proac Tablette Ten speakers, I think they're around 87 db efficiency, not ported. I listen to soul jazz, wes montgomery, grant green, jimmy smith etc. at moderate volume in a mid sized room and od crank it up sometimes. I read the input gain on the F5 is on the low side, requiring a higher output pre amp or a higher volume setting on your pre. I probably prefer a higher input gain amp and tend to like higher current amps...should I look at something other than the F5 or F5 turbo or do you think it's still a great choice ? thanks !
Thanks for the advice! After having done some homework reading on the various Pass amp build kits avail here I'm trying to figure out which one makes the most sense for me. I'll probably run a pair of Proac Tablette Ten speakers, I think they're around 87 db efficiency, not ported. I listen to soul jazz, wes montgomery, grant green, jimmy smith etc. at moderate volume in a mid sized room and od crank it up sometimes. I read the input gain on the F5 is on the low side, requiring a higher output pre amp or a higher volume setting on your pre. I probably prefer a higher input gain amp and tend to like higher current amps...should I look at something other than the F5 or F5 turbo or do you think it's still a great choice ? thanks !
Monobloc 1 of 2 done. This is the V3 turbo I’m making for a good friend. Unfortunately I’m all dressed up with nowhere to go. Either my buddy didn’t order fuses or I misplaced them in my messy work area. I’ll order fuses and get to work on another amp. I can’t wait to fire this up, get it biased, and hear it rock.
Attachments
@acowans, with 87dB efficiency in a mid sized room I think you'll definitely want one of the push-pull designs. (They can go into class AB whereas the single-ended ones just clip when they run out of class A room.)
I'm using my F5 right now on Maggie .7s (similar efficiency) in a 20' x 30' x 15' room, and it doesn't quite even get to moderate volume. Depending on your definition of "mid sized", you might want to look at the turbo (or BA-2 or -3).
Cheers,
Jeff.
I'm using my F5 right now on Maggie .7s (similar efficiency) in a 20' x 30' x 15' room, and it doesn't quite even get to moderate volume. Depending on your definition of "mid sized", you might want to look at the turbo (or BA-2 or -3).
Cheers,
Jeff.
Hi acowans,
Assuming you have an amp that can drive your speakers to the volume you desire,
I suggest you try this test:
A Test. How much Voltage (power) do your speakers need?
You can get an idea of how much max voltage swing you need and from them figure out
if the F5 might be adequate.
Cheers,
Dennis
Assuming you have an amp that can drive your speakers to the volume you desire,
I suggest you try this test:
A Test. How much Voltage (power) do your speakers need?
You can get an idea of how much max voltage swing you need and from them figure out
if the F5 might be adequate.
Cheers,
Dennis
After a week of playing with bias settings, letting the while amp get up to temperature - takes a surprisingly long time, I plugged them into my ESL57s. They certainly reveal a little more detail than my Avondale Voyages, but I'm not convinced as to their pace. More listening needed.
I haven't fitted a thermistor between the 0v and the chassis though I have fitted the safety earth through a diode bridge. The only hum is mechanical from the transformer. Other than that the amp is silent.
Preamps so far have been a WHAMMY (not sure what opamp it has installed!) and a PFM B4. The B4 runs out of volume as it is only a buffer with no amplification.
I haven't fitted a thermistor between the 0v and the chassis though I have fitted the safety earth through a diode bridge. The only hum is mechanical from the transformer. Other than that the amp is silent.
Preamps so far have been a WHAMMY (not sure what opamp it has installed!) and a PFM B4. The B4 runs out of volume as it is only a buffer with no amplification.
No hole yet. They can drill anything. I only found this one rated 250VAC/10A, but it's short, I couldn't use a nut.
https://cz.mouser.com/ProductDetail/Schurter/3-108-979?qs=sGAEpiMZZMvxtGF7dlGNpgFlOBPHp9G0jOEuhAY8gXc%3D
I was still thinking that I could turn off the 12V power for relay in the soft start board. I don't know if it's a safe choice when the soft start input circuit is still under 240V.
https://cz.mouser.com/ProductDetail/Schurter/3-108-979?qs=sGAEpiMZZMvxtGF7dlGNpgFlOBPHp9G0jOEuhAY8gXc%3D
I was still thinking that I could turn off the 12V power for relay in the soft start board. I don't know if it's a safe choice when the soft start input circuit is still under 240V.
Pavel,
I think this would defeat the soft-start function of the soft-start as the caps are permanently charged if not mistaken it would fry the resistors as well - I might be wrong though.
I suggest you check the soft-start thread and understand how the circuit works and go from there.
Max
I think this would defeat the soft-start function of the soft-start as the caps are permanently charged if not mistaken it would fry the resistors as well - I might be wrong though.
I suggest you check the soft-start thread and understand how the circuit works and go from there.
Max
Hi All. I am thinking about building an F5T but have only built tube amps. I have some questions.
1. do I have to use a toroidal PTX....that is all I see in the builds I've been looking at.
2. I don't see anything that looks like an output transformer. Do they have one?
3. Is the F5T SS, digital, or something else?
4. I see boards for sale on DIY store but not a PS board specific to the F5T.
5. Where is the best place to buy the boards?
Sorry for all the stupid questions....I just don't know this stuff.
I had a Hafler amp for a month now (borrowed) and found that a good SS amp going through a tube preamp sounds very good.
Thanks for your help.
1. do I have to use a toroidal PTX....that is all I see in the builds I've been looking at.
2. I don't see anything that looks like an output transformer. Do they have one?
3. Is the F5T SS, digital, or something else?
4. I see boards for sale on DIY store but not a PS board specific to the F5T.
5. Where is the best place to buy the boards?
Sorry for all the stupid questions....I just don't know this stuff.
I had a Hafler amp for a month now (borrowed) and found that a good SS amp going through a tube preamp sounds very good.
Thanks for your help.
1. You can use whatever transformer you want as long as it meets your requirement.
2. F5T does not use an output transformer.
3. F5T is a solid state/transistor amp.
4. You can build your own power supply to spec. This could be point to point on a breadboard or there are PCB solutions out there on the interwebs.
5. The diyaudiostore.com has a universal power supply PCB and F5T PCBs available. you could also have your own made if you want to go that route.
Thanks Airborne. I saw the universal PS board but wasn't sure it if would work. I am going to a surplus store tomorrow and they have the wildest looking heat-sinks and rows of electronic gear I can buy for cheap to use for the chassis.
I have not been able to find the PTX specs for the F5T. But I'll keep looking.
I have not been able to find the PTX specs for the F5T. But I'll keep looking.