No - The F5m would not be recommended for an ACA chassis.
You could... if you wanted... build the ACA or the ACA MinMax in a bigger chassis, then use that chassis for a First Watt when or if you wanted.
You could... if you wanted... build the ACA or the ACA MinMax in a bigger chassis, then use that chassis for a First Watt when or if you wanted.
This one? Mini Dissipante 3U 300mm 10mm BLACK front panel - 2mm aluminium covers and 3mm rear panel
The F5m is in a different class , as are other 25W First Watt amps and clones. The 25W amps need a chassis around 4U x 350mm or larger, depending on voltage and bias.
The question is whether to build a starter amp (certainly fun), or an amp that will last for your current speakers and the best speakers you can imagine having a few years down the road.
Though I enjoyed the various ACA amps over the couple years when I was experimenting with that style, none of them stayed on my power amp rack longer than the F5m has. The Aleph J and F6 have had extensive play as well (including a revisitation of the F6 circuit). I found a way of tuning the F5m, using standard F5 PCBs, that sounds just right with my speakers. That effort was covered in the first F5m thread.
This really is about the journey
The question is whether to build a starter amp (certainly fun), or an amp that will last for your current speakers and the best speakers you can imagine having a few years down the road.
Though I enjoyed the various ACA amps over the couple years when I was experimenting with that style, none of them stayed on my power amp rack longer than the F5m has. The Aleph J and F6 have had extensive play as well (including a revisitation of the F6 circuit). I found a way of tuning the F5m, using standard F5 PCBs, that sounds just right with my speakers. That effort was covered in the first F5m thread.
This really is about the journey
Great advice Tungsten, thanks. I'll build the F5m. I'll dig into that thread and docs to determine what voltage and bias. I wonder if I should order the F5m kit now in case it goes out of stock... not sure if I need the double transformer or not 😉
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Just curious... I'm looking at the F5m doc and they show Diss 3U as a case option. I see the 300VA 22V transformers are in stock and would use those. ( 2 monoblocks ) The PassDIY 4U is out of stock... any other options out theres?
Are you building monoblocks or a stereo amp? (1 or 2 chassis?)
You want transformers of 18+18VAC or 20+20VAC, 22 is getting too high for F5m.
You want transformers of 18+18VAC or 20+20VAC, 22 is getting too high for F5m.
I plan on building 2 monoblocks.
Are the transformers shown in the F5m doc ok or have those changed to other values? I'm guessing alternate values are used when there is no stock...
Also, the F5m doc suggests chassis, one of which is the Diss 3U. I don't mind getting a 4U from Italy as suggested, but they are a bit expensive and look VERY NICE. Is there a reason not to use 3U? I would have thought the doc would mention something about it. If it's just a matter of having more room for dissipation than that is good enough for me. I'm just trying to think of what else would need to go int he case, 2 transformers and boards.... heat sinks are outside the case... ( appreciate the heads-up on the 4U since they are so nice and back in stock in September )
Are the transformers shown in the F5m doc ok or have those changed to other values? I'm guessing alternate values are used when there is no stock...
Also, the F5m doc suggests chassis, one of which is the Diss 3U. I don't mind getting a 4U from Italy as suggested, but they are a bit expensive and look VERY NICE. Is there a reason not to use 3U? I would have thought the doc would mention something about it. If it's just a matter of having more room for dissipation than that is good enough for me. I'm just trying to think of what else would need to go int he case, 2 transformers and boards.... heat sinks are outside the case... ( appreciate the heads-up on the 4U since they are so nice and back in stock in September )
Post in thread 'Pass F5m'
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7618191
Or, how to build an F5m without building an F5m. Call it an F5m+ if that seems better suited. This is distinguished by the use of high transconductance Fets and higher voltage. Bias current is set where it sounds best. Note the use of a single chassis, enhanced by copper plates, a single power transformer and large motor run capacitors tied into each channel.
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7618191
Or, how to build an F5m without building an F5m. Call it an F5m+ if that seems better suited. This is distinguished by the use of high transconductance Fets and higher voltage. Bias current is set where it sounds best. Note the use of a single chassis, enhanced by copper plates, a single power transformer and large motor run capacitors tied into each channel.
I'm looking at the monoblock from Modushop now, @Halauhula. What makes this preferable over the PassDIY? I though monoblock was just a matter of bridging the 2 amps together inside the case. Is it because I"ll be using only 1 transformer for a monoblock? ( I'll be looking into this further today so I understand better ) I do see it's a bit smaller.
usual arrangement is common PSU for both channels in one case
dual mono is each channel having own PSU in common case
monoblock is each channel with own PSU in separate case
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bridging of two channels is different issue, matter of functional arrangement, not constructional arrangement
dual mono is each channel having own PSU in common case
monoblock is each channel with own PSU in separate case
edit:
bridging of two channels is different issue, matter of functional arrangement, not constructional arrangement
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Ah, ok that makes more sense now. I can see how having a larger case is required for dual mono. I ordered 2 'F5m' kits with 4 power supply boards. I was under the impression I would build 2 channels into each case, but bridge them to get monoblock. I ordered the extra power PCB just in case I needed 2 PSU. Is one of the benefits of dual monoblock that is can easily be used as stereo? I don't want to snooker myself out of a better design as I learn new info.
@TungstenAudio what case config do you use for your preferred setup?
@TungstenAudio what case config do you use for your preferred setup?
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What if I build the common PSU for both channels in 1 case, and build 2 cases? Could I then 'bridge' each 2-channel case to end up with 2 'monoblocks'? ( maybe that is overdoing it )
I definitely don't want to end up with 2 power cords going into each monblock! hahaha!
I definitely don't want to end up with 2 power cords going into each monblock! hahaha!
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I guess bridging would affect the quality of the output signal so I'll stay away from that: "Bridging cuts the damping factor in half and increases the noise floor." So what advantage other than aesthetic and speaker cable length is there to a monoblock over a dual mono? If the amps are well-built, I'm guessing there is no cross-talk to worry about with 2 in 1 case. Would heat sinks be larger with 2 monoblocks?
"I definitely don't want to end up with 2 power cords going into each monblock!"
That will really look funny.
You made me laugh.
On a more serious note, yes, you can do that, bridge two channels per case and get 2 mono blocks. Or run them in parallel and also get 2 mono blocks. Or build two channels with their own PSUs in one case, that's dual mono, only the power cord is shared. And many other combinations with what you've got.
Download a copy of FirstWatt F4 manual and read it carefully a few times. You'll find a lot of your questions are answered there.
That will really look funny.
You made me laugh.
On a more serious note, yes, you can do that, bridge two channels per case and get 2 mono blocks. Or run them in parallel and also get 2 mono blocks. Or build two channels with their own PSUs in one case, that's dual mono, only the power cord is shared. And many other combinations with what you've got.
Download a copy of FirstWatt F4 manual and read it carefully a few times. You'll find a lot of your questions are answered there.
"The F5m does not need to be ‘bridged’. One board per channel, two boards in a stereo chassis."
roger that. is there ever a config where 2 channels are run in parallel as a monoblock? I guess they can be run as bi-amp too which the Klipsh speakers I'm looking at have. Just want to make sure I don't paint myself into a corner with my beginner level 1st attempt.
roger that. is there ever a config where 2 channels are run in parallel as a monoblock? I guess they can be run as bi-amp too which the Klipsh speakers I'm looking at have. Just want to make sure I don't paint myself into a corner with my beginner level 1st attempt.
I recommend building a standard two channel amp first. If your speakers support bi-amping, then a second two channel amp may be connected externally.
But definitely keep things simple to begin with. I think you will be very pleasantly surprised by how good a 25W Class A amp sounds. It will drive your speakers louder than is comfortable for most people.
But definitely keep things simple to begin with. I think you will be very pleasantly surprised by how good a 25W Class A amp sounds. It will drive your speakers louder than is comfortable for most people.
Great, thanks for steering me in the right direction. I'll do just that. Maybe I'll use 2 PSU in the case. If I end up using them as bi-amps, will having 2 power supplies be required at that time, or should I stick to 1 PSU for both channels? I think my analog synths and analog drum machine will sound quite good with the standard build. ( better than the QSC, EV PAs, and Roland KC 600 keyboard amp ( aka mystery box ) everyone recommends these days anyhow )