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Oh Lord, another DAC


rabski
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Because, why not? I'm very happy with the sound and presentation of the current one, but there are two issues. First, it runs hot. And I mean seriously hot. It's using 5687 valves, which are like room heaters anyway, three valves in the power supply, and there's very little space. Second, I'm not 100% happy with the regulated HT supply. There is a tiny bit of hum, though you need to wind the wick right up to hear it, but apart from phono stages, I remain unconvinced that on balance, regulated HT is an advantage. So, based on the fact that I have no spare time at all, I thought I'd spend a bit of it throwing together a new version.

This will be similar to the last one in the digital department, and using my only remaining off-the-shelf board with an AD1865 and an AK4118 reciever. The first major difference is that it's a two-box layout, so power supply totally separate. The bits below are the start of the PSU. Valve rectifier board, with 'classic' CLCRCRC filter, with a final RC to provide a filament lift supply. Running it in PSUD, I've got an estimate of under 0.2uV ripple, which ought to be quiet enough. The bottom board is a low-voltage medium current regulator for the filaments. The 'stack' on the left is three, ultra-low-noise regs for the digital supplies. The second box will be similar to the current DAC, with Lundahl trasnformers for I/V, but I'm going to use octal output valves, plus a few tweakettes.

Hopefully get the power supply finished and cased up tomorrow.

psu-parts.jpg

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Incoming: apparently you can actually just buy DACs off-the-shelf these days. Who would have thought! I think you'll agree that this represents real progress.

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Enjoy. Two-box just has to be the way to go.

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2 minutes ago, TheFlash said:

Incoming: apparently you can actually just buy DACs off-the-shelf these days. Who would have thought! I think you'll agree that this represents real progress.

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Enjoy. Two-box just has to be the way to go.

It's a happy mix of a small amount of ability combined with a small amount of money, and a dislike of wasting either.

I have in the past spent by my own standards inordinately large sums of money on DACs. I have also borrowed, auditioned, reviewed and generally listened to one or two. Most of them do not enirely 'float my boat', as I believe you young people say. In fact, more than a few have come closer to 'sinking my yacht'. That's not to mention the ones that I found so dreadful as to be near unlistenable, of which there are more than there ought to be.

Plus I enjoy doing it. It keeps me off the streets and prevents me from getting involved in camping, line dancing or other unspeakable acts.

Others' ears seem to confirm my suspicions that the stuff I nail together doesn't sound total rubbish and making it it makes me if not happy, then at least slightly less miserable than before I started. Hopefully you'll be at Kegworth, and assuming all goes as expected, you can tell me it's average and we'll all be happy.

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That is an impressively over the top power supply. Probably beats as a power source some ridiculously over priced  Hifi units.

I kook forward to hearing the result at Kegworth.

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11 hours ago, rabski said:

It's a happy mix of a small amount of ability combined with a small amount of money, and a dislike of wasting either.

I have in the past spent by my own standards inordinately large sums of money on DACs. I have also borrowed, auditioned, reviewed and generally listened to one or two. Most of them do not enirely 'float my boat', as I believe you young people say. In fact, more than a few have come closer to 'sinking my yacht'. That's not to mention the ones that I found so dreadful as to be near unlistenable, of which there are more than there ought to be.

Plus I enjoy doing it. It keeps me off the streets and prevents me from getting involved in camping, line dancing or other unspeakable acts.

Others' ears seem to confirm my suspicions that the stuff I nail together doesn't sound total rubbish and making it it makes me if not happy, then at least slightly less miserable than before I started. Hopefully you'll be at Kegworth, and assuming all goes as expected, you can tell me it's average and we'll all be happy.

Nice one Richard.

In para 2, I think it's a wise move not to name the names of those DACs you consider to be unlistenable, though that adjective does strike a chord.

It's ok building the things but you're missing an opportunity to make a serious dent on the hifi industry with your specialised one-off tailor-made custom-built reference quality extreme DACs. You will of course need a brand and a strapline but the first is pretty obvious. I mean, who wouldn't one of Dick's DACs? Strapline: They Swing. No, don't worry, not giving up the day job.

Having made the cunning strategic decision to live within 10 mins drive of Scalford in anticipation of the first Wam Show a mere 20 years later, I am fortunate to find myself only 30 mins from Kegworth. No do-I-don't-I brainache about which of the days to attend and whether to make it an overnight... see you there.

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3 hours ago, Tony_J said:

Pun intended...? :nerves:

:whistle:

Edited by TheFlash
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Although I haven't fallen head-over-heels for any that I've heard, I don't have any issue with Chord DACs. I have yet to listen to a Dave at any length, but it's off my radar anyway, as it's way out of my comfort zone in price terms. That's not a criticism, it's simply that digital has never been, and is never likely to be, a primary source for me. Thus there is no way I could justify that sort of spendiness, even if I wasn't happier to DIY stuff. I don't agree with all their statements in tech terms, but a lot do make sense to me and at least they tread a different path than just picking a standard converter chip off the shelf and making small changes in the analogue stage. What I really don't get on with is the Fisher Price visual 'appeal', but that's just down to my taste.

My own hit list is susprisingly extensive, but mostly includes things that apparently 'measure perfectly' and therefore apparently ought to sound the same. Except they don't. The main differences seem to lie in the distance at which they can strip wallpaper with the horrendous, gratingly harsh and unrealistic top end. Peter Walker used to get away with measuring and not auditioning, because in the pure analogue realm of the 1950s and 1960s, certain artefacts were limited in their potential impact. When you start playing with stuff that has MHz harmonics and solid state devices that can easily be affected, things get a wee bit more complex. Nevertheless, I have to conclude that either some manufacturers have never heard their products in the wild, or if they have, then their only exposure to real instruments has been limited.

No. I'm not naming anything. More than a few people have expressed their happiness to live forever with some of the ones on my list of ear damage suspects, and presumably buy a cottage in the country and make babies with them for all I know.

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10 hours ago, slavedata said:

That is an impressively over the top power supply. Probably beats as a power source some ridiculously over priced  Hifi units.

I kook forward to hearing the result at Kegworth.

Not as ‘rediculous’ as some psu’s used with DACs that have been discussed  used elsewhere on here

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On 23/08/2021 at 18:19, MF 1000 said:

Not as ‘rediculous’ as some psu’s used with DACs that have been discussed  used elsewhere on here

I think that's what Dave was referring to.

Power supplies can and do make a huge difference to the performance of a DAC and/or a streamer; more than most of us would have imagined until we were daft enough to try it. Daft? Well, it can induce wallet-pain, though I've never had the acute variant of the disease.

Far better to do what the right honourable Rabski is doing: actually buy a big transformer and some actual other great stuff and do an actual build into an actual DAC. The trouble for many of us is that we're still working our way through the Idiot's Guide to Choosing and Using a Lefthanded Screwdriver.

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53 minutes ago, TheFlash said:

Far better to do what the right honourable Rabski is doing: actually buy a big transformer and some actual other great stuff and do an actual build into an actual DAC. The trouble for many of us is that we're still working our way through the Idiot's Guide to Choosing and Using a Lefthanded Screwdriver.

@rabski I wonder have you considered not having the PS in the same box as the DAC?

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6 minutes ago, Fourlegs said:

@rabski I wonder have you considered not having the PS in the same box as the DAC?

That's what two box implies Nick :rofl:

Bits in the first post above are just the power supply. DAC and analogue section will be in t'other.

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7 minutes ago, Fourlegs said:

@rabski I wonder have you considered not having the PS in the same box as the DAC?

He said it's a two box build with separate psu in the first post. Regards Andrew 

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23 minutes ago, rabski said:

That's what two box implies Nick :rofl:

Bits in the first post above are just the power supply. DAC and analogue section will be in t'other.

Haha, see what you did there  with “Bits in the first post . . . “.

Anyway, how was I to tell, two box might have had all the ‘0’s in one box and all the ‘1’s in the other box. 

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Just now, Fourlegs said:

Haha, see what you did there  with “Bits in the first post . . . “.

Anyway, how was I to tell, two box might have had all the ‘0’s in one box and all the ‘1’s in the other box. 

They may well be Nick. With luck, I will get the 0s and 1s in the correct place. Not necessarily in the correct order (thanks Eric) of course.

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2 hours ago, rabski said:

They may well be Nick. With luck, I will get the 0s and 1s in the correct place. Not necessarily in the correct order (thanks Eric) of course.

Or could that be Les ?

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