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F5 build wrap-up (DiyAudio Pass FirstWatt)

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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I wanted to keep my system really simple in terms of switching on and off so all the family could use it without loads of switches. So I use a heavy duty mains relay in the F5 with a socket on the back that feeds the low voltage relay switching voltage from the pre-amp. The pre-amp has the extra PSU for the relay and an off switch on the front panel. This could avoid any switches on your beautifully built F5.

Just a thought
Ian
 
IDM said:
I wanted to keep my system really simple in terms of switching on and off so all the family could use it without loads of switches. So I use a heavy duty mains relay in the F5 with a socket on the back that feeds the low voltage relay switching voltage from the pre-amp. The pre-amp has the extra PSU for the relay and an off switch on the front panel. This could avoid any switches on your beautifully built F5.

Just a thought
Ian
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That's an interesting idea! I had considered putting a 'switched out' male IEC on the preamp so the F5 could turn on/off via the preamp power switch. It should be fine since the F5 has soft start and speaker delay.

I really like these aluminum knobs I found on a Spanish site (don-audio.com). They come in several sizes and I could see making my preamp aesthetically similar to a vintage Mark Levinson:

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And I wouldn't mind using a rotary switch for power in that build. But for some reason having a lone power knob poking out of a giant black faceplate on the amp seems strange.

I should probably wait until I have my preamp project started and have picked a chassis before I commit to any design/parts.
 
I've also considered a rocker switch (e.g. black rectangular, no illumination) but as far as I can tell they are all made to snap in to panels less than 2mm thick. Some really nice vintage amps (Mark Levingson, Krell), used rocker switches in thick faceplates. I guess if you were confident with hiring out CNC jobs you could have a rectangular hole that is undercut from the backside.

Anyway, keep the ideas and suggestions coming!
 
booja30 said:
I've also considered a rocker switch (e.g. black rectangular, no illumination) but as far as I can tell they are all made to snap in to panels less than 2mm thick. Some really nice vintage amps (Mark Levingson, Krell), used rocker switches in thick faceplates. I guess if you were confident with hiring out CNC jobs you could have a rectangular hole that is undercut from the backside.

Anyway, keep the ideas and suggestions coming!
Click to expand...

I recently fitted a rocker switch in a 10mm panel:
- Remove the "clicky ratchet" plastic tabs on the switch - scalpel then a bit of sanding
- Drill and file out the panel until the switch is a nice interference fit (I didn't need glue, but if you go too far a dab of hot melt glue could be used)

I used sticky-back plastic to protect the front panel during the drilling etc.

This feels way more solid that "back-filing" the cutout and using the plastic tabs. It is VERY labour intensive though :-(
 
I never followed up on this thread, but after 'completing' this build I ended up building a BA2018 preamp (design by a Pass employee) and sticking it in a similar chassis. I ended up having custom faceplates CNC'd by ModuShop so I could have low key power LEDs and toggle switches on the front. The amp is in a ModuShop Deluxe 4U and the pre is in a ModuShop SlimLine 2U. Both have 10mm aluminum faceplates and 3mm aluminum covers. I designed and 3D printed protective covers over any exposed mains in both boxes. You could still get shocked poking around with a screwdriver, but it's enough to keep fingertips safe.

Here's how they turned out:

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Many more photos here.

I finished these in late summer in Valencia and started using them. I quickly came to realize that running the amp for any reasonable amount of time lead to sweating or running the AC. I don't like wasting energy and realized these belonged in a colder region where generated heat would be a beneficial side effect. So I sold them to a fellow PFMer last month. They were a great project, but I don't think I'd build class A again -- I don't hear enough of an improvement personally to make me ditch AB. Also, I like the experience of making things more than the final product, so I didn't really mind giving them up. BTW, my next project was a huge overhaul of a 40 year old Sansui AU-717. It's a beauty.
 
Rosewind said:
Looks nice! I still have that F4 if you fancy a go at finishing it.
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I'd definitely consider it now that the F5 and BA2018 are gone and the Sansui is finished. The only problem I foresee is transport. It took a lot of planning and foam crafting to get the F5 safely packed for transport. And the cost was £88 to send the amp from Spain to the UK via UPS. Since we're both on the mainland it's probably half that each way, but still, not cheap!
 
UPS (aka Oops!) came out as markedly worst of a not-very-good bunch for customer service in a recent Which survey - for what that's worth.
 
booja30 said:
I never followed up on this thread, but after 'completing' this build I ended up building a BA2018 preamp (design by a Pass employee) and sticking it in a similar chassis. I ended up having custom faceplates CNC'd by ModuShop so I could have low key power LEDs and toggle switches on the front. The amp is in a ModuShop Deluxe 4U and the pre is in a ModuShop SlimLine 2U.
Click to expand...

Was the 4U mainly for the enormous heatsink capacity? It doesn't look as if you needed all that interior volume.

BugBear
 
bugbear said:
Was the 4U mainly for the enormous heatsink capacity? It doesn't look as if you needed all that interior volume.
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Yes, the Modushop 4U Dissipante chassis has the minimum recommended heatsink area for the 25w Pass class A designs according to DiyAudio. I know people go smaller if they turn down the bias current, use smaller transformers, maybe fans even. But like I mentioned earlier, I sold this because it was too hot for our apartment, and I personally wouldn't have wanted to risk going smaller with this design.

It actually felt cramped to work in at times, and some people go with the deeper chassis or even 5U (overkill). You need access to the trim pots on the amp boards during setup, and I can see how a smaller space would have been a headache. The only reasons I was able to make it seem more roomy were that I tapped and drilled the faceplate to mount the PSU board vertically, and I designed and 3D printed a bracket to put speaker protection above the transformer. The PSU board wouldn't have fit laying flat with that transformer, and the wiring would have been a lot less tidy with speaker protection on the bottom. For anyone wanting to do one of these 25w class A projects with a soft start board and speaker protection board, I'd say this was the minimum space for a sane build experience.
 
S-Man said:
UPS (aka Oops!) came out as markedly worst of a not-very-good bunch for customer service in a recent Which survey - for what that's worth.
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You mentioned that in another thread I think, and I looked it up. All the carriers had fairly miserable reviews, and I think it's because you probably don't go to TrustPilot or whatever to write a review after you've had a good experience. UPS here has been great. Uniformed drivers will show up to do a pick up with very short notice, usually the same guy. Never an unmarked white van. Tracking is reliable, and I've never had a package miss the estimated delivery date.

My worst experiences have been with SEUR (part of DPD I think). They've delivered larger items to us (tower fans, dehumidifiers, etc.) that had to go back because of mangled packaging that damaged the items inside. It hasn't been great.
 
Agree. Like I said "FWIW".
It is entirely possible that Oops drop fewer parcels, but just have worst customer service when they do.

I always remember getting a washer dryer because it came out top in a Which review.
A couple of years later it featured on Watchdog for being a fire starter.:eek:
 
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