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F5 build wrap-up (DiyAudio Pass FirstWatt)

Both DCG3 and DCB1 are fabulous preamps but I would suggest DCG3 because of the lowish gain of F5. The same goes for B4 and AD815, I'd prefer AD815.
Generally I'd say preamp with gain have more dynamic presence but let's say this is just a plus not something that is missing from buffer/unity gain ones.

I would only go for unity gain/buffer if I have the chance to hear them in my system and conclude that there is no problem in driving the power amp.

All of them are sensitive to power supply quality. Although I did not had the chance for A/B comparison for B4, for the rest I can tell you that with certainty.
Even DCB1 which includes the regulator is sensitive to bridge and capacitor change. That's good news if you want to tailor the sound to your liking

Enjoy!
 
ramona said:
Both DCG3 and DCB1 are fabulous preamps but I would suggest DCG3 because of the lowish gain of F5. The same goes for B4 and AD815, I'd prefer AD815.
Generally I'd say preamp with gain have more dynamic presence but let's say this is just a plus not something that is missing from buffer/unity gain ones.

I would only go for unity gain/buffer if I have the chance to hear them in my system and conclude that there is no problem in driving the power amp.

All of them are sensitive to power supply quality. Although I did not had the chance for A/B comparison for B4, for the rest I can tell you that with certainty.
Even DCB1 which includes the regulator is sensitive to bridge and capacitor change. That's good news if you want to tailor the sound to your liking

Enjoy!
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Thanks for the advice. I think I will start with the Mezmerize B1 because it's available now and fairly inexpensive to build. Then I can have something to play around with while I wait for another release of DCG3. Since as far as I can tell they're both designed for rotary input selectors (and of course volume) I can design the same chassis/knobs for both with flying leads if necessary.

I guess it would make sense to find out now if I can use the same spec transformer for both preamps....
 
ramona said:
Both DCG3 and DCB1 are fabulous preamps but I would suggest DCG3 because of the lowish gain of F5. The same goes for B4 and AD815, I'd prefer AD815.
Generally I'd say preamp with gain have more dynamic presence but let's say this is just a plus not something that is missing from buffer/unity gain ones.

I would only go for unity gain/buffer if I have the chance to hear them in my system and conclude that there is no problem in driving the power amp.

All of them are sensitive to power supply quality. Although I did not had the chance for A/B comparison for B4, for the rest I can tell you that with certainty.
Even DCB1 which includes the regulator is sensitive to bridge and capacitor change. That's good news if you want to tailor the sound to your liking

Enjoy!
Click to expand...

I compared the B4 (no gain) to the DIYAudio Whammy (some gain) and never found the F5T to be lacking in gain. I was driving the pre-amps from a iqaudio DAC on a PI.
 
chiily said:
I compared the B4 (no gain) to the DIYAudio Whammy (some gain) and never found the F5T to be lacking in gain. I was driving the pre-amps from a iqaudio DAC on a PI.
Click to expand...
That would be my primary source as well (IQaudiIO DAC), so good to know... I wonder what double the wattage from your F5T vs. the F5 would mean wrt gain requirement.
 
I'm not an NP amp expert but I suppose that F5T has 22 db, not far from 26-27db normal A-B amp but still you better test it (with all sort of music) to be on the safe side especially if you have analog source too.
DCG3 and B1 (DIYA store) have different output connector pitch, better find a connector for B1 which can take bare wire so switching would be easy.

BTW great build, do report back your impressions. Most that put F5 aside, write something about being too analytical and in other hand the ones that love it that it simply has lots of details.
 
I'd rather do something with gain like the Salas DCG3 that folks have recommended, but I missed the most recent group buy and don't have the patience to wait out the next batch.
Click to expand...

If you PM Tea-bag on DIYaudio who organises the DCG3 group buys he may have what you need. Salas recommended I reach out to him when I wanted to build a DCG3 and he sorted me out.

Cheers
Ian
 
IDM said:
If you PM Tea-bag on DIYaudio who organises the DCG3 group buys he may have what you need. Salas recommended I reach out to him when I wanted to build a DCG3 and he sorted me out.

Cheers
Ian
Click to expand...
Thanks for the suggestion. I PM'd Tea-Bag a few days ago and he said the next GB might yield boards in the next 6 weeks or so. It's tempting, but I don't know if I want to wait that long. :)
 
this is it running bypassed the input select as there was already on in the chassis
after removing a B4 buffer and ice power class D to make a preamp to try it
sounds very good as it should but i need something with a bit more gain than unity
as for the solder pad its through hole and just the front bit its soldered fine on the back where the track is
not long since built it with original fets 4 matched and 6 un matched 2sk170bl
will have to work out what it owes me
20200305_140209 by glenn jarrett, on Flickr
20200305_105037 by glenn jarrett, on Flickr
20200305_115716 by glenn jarrett, on Flickr
 
glenn jarrett said:
sounds very good as it should but i need something with a bit more gain than unity
Click to expand...
That sound like my dilemma... It seems like some people say the B1 is fine with the F5, but others suggest something capable of at least 2x gain to get the most out of it.

Thanks for the photos! I have some thinking to do.
 
It depends on your listening levels, room and your source output voltage.
You could first decide the gain factor, buffer or with gain, and then go for a particular design.
Anyone nearby with B4 or B1 (both with no gain)? Such a good build for power amp needs a good mate, don't haste on your decision.
 
I was thinking of adding a power switch to the front panel of this amp. It might have a preamp sitting on top of it at some point and reaching around behind it to flip the IEC switch might be a PITA.

I haven't found a DPST push button switch that is black with no illumination that I like so far. I was thinking of using an internal switch and then making (probably 3D printing) a shaft to connect it to a small black push button through the fascia. While I've found tons of options for metal knobs (e.g. for 6mm shafts), I don't know where to find a source for metal 'buttons'.

To clarify, I'd like to have a cosmetic button that passes through the 10mm faceplate and connects to an internal power switch via some linkage (that I can make). Similar to the power switch style on a Rega Brio, Quad 34/306, Sony TA-F3000, etc.

Any ideas? Am I just using the wrong search terms?

Thanks in advance

BTW the reason I want DPST (or DPDT) for the switch mechanism is that I'm in Spain, and we have non-polarized Schuko plugs here, so you can't assume anything about which of the L/N leads is energized.
 
Excellent build, this is one of the cleanest F5's I've seen.
I built an F5 as well, it sounded excellent but had to sell it off.... luckily they are in high demand and it sold within a day.

Did you find a preamp yet? I used the F5 with a Schiit Saga which doesn't have gain (just a buffer) and that was a bit limited with the F5.
I've built the B1 Korg which has 12dB gain (or 15dB, I forget) gain and should work well... although you may get too much of that second harmonic goodness for your liking.
Another excellent preamp but is a bit more involved is is the AMB alpha10 which is what I use now. It has great flexibility with remote control, relay based I/O switching and volume control.

For a front button, what about one of those Bulgin momentary push buttons? AMB has a board for it: https://www.amb.org/audio/epsilon24/
Another route is swapping out the DAS soft-start module with this one: https://neurochrome.com/products/intelligent-soft-start
It supports momentary buttons and has a bit more advanced circuitry

(added a photo so you get an idea which button I am referring to)
9yExA6c.jpg
 
Thanks for the compliment. Your build is very professional looking! Like something you could actually buy somewhere, not a kit! :)

I'm currently enrolled in the next group buy for a Salas DCG3. I had considered the DiyAudio Mezmerize B1 but heard enough people say unity gain might not be enough. Also, it uses 10 JFETs, 4 of which need to be matched, and DiyAudio won't sell unmatched cheaper. So it would have been $90 or so just for JFETs for a preamp I may or may not like...

For the power button I'd prefer something really low key. I was thinking along the lines of a 5mm hole through the faceplate with a captive black anodized rod barely protruding. Your MC idea might work well for something like that since the stroke of a mechanical push button would be longer and require a button that sticks out more. A little MC switch operating a relay would only move like a mm or so, so the switch could be really small and flush.
 
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That looks like an excellent build, congratulations! I still have my over-the-top F1 clone built years ago to service the AKG K-1000. Luckily I was able to get away with a 3U 300mm enclosure as the dissipation is lower.

Speaking of power switches, if you want a low key, non-obtrusive switch, why not add it to the bottom plate, near the front left or right corners (whichever is most convenient). That way, you only reach slightly below the amp (which needs to be risen on small feet anyway) to turn on/off and you do not need to do anything to the front plate. Pretty much all of the electronics I have built have had power switches in that location - I cannot be brought to disrupt the cleanliness of the front plates.
 
InSides said:
That looks like an excellent build, congratulations! I still have my over-the-top F1 clone built years ago to service the AKG K-1000. Luckily I was able to get away with a 3U 300mm enclosure as the dissipation is lower.

Speaking of power switches, if you want a low key, non-obtrusive switch, why not add it to the bottom plate, near the front left or right corners (whichever is most convenient). That way, you only reach slightly below the amp (which needs to be risen on small feet anyway) to turn on/off and you do not need to do anything to the front plate. Pretty much all of the electronics I have built have had power switches in that location - I cannot be brought to disrupt the cleanliness of the front plates.
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That's a good idea. Maybe a small DPST rocker switch...

On second thought I just had a look at my amp on the shelf (collecting dust for now) and with the feet it came with I can't even fit my pinky under it. Might need to lift it up on some big puck feet. Remember in the '90s when big gold tuna can feet were popular under otherwise black Japanese amps? :)
 
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