A DAC for ye olde 70's receiver

[Jambo]

Yo dudes of the x and y axis.

I've been reading in here for some days. You know to hopefully gather knowledge. You guys certainly know a thing or two, but thing is, I don't. The more I read the weirder it gets.

I'm just a guy with a stereo (Marantz 2270) and some speakers (Amphion Argon 3L), and I'd like to know what's up with them DACs.

I normally listen to vinyls, but I'm debating with myself if I should buy into one of them hifi-streaming-services out there.

Hence the DAC. Do I need one?

I mean judging by some of your posts about them it seems that the audible differences between them range from small to not at all.

I'm not interested in measurements. I want sound.

Should I buy one (WHICH ONE FOR GOD'S SAKE) or just crawl back to my cave?

 

[Robin L]

Yo dudes of the x and y axis.

I've been reading in here for some days. You know to hopefully gather knowledge. You guys certainly know a thing or two, but thing is, I don't. The more I read the weirder it gets.

I'm just a guy with a stereo (Marantz 2270) and some speakers (Amphion Argon 3L), and I'd like to know what's up with them DACs.

I normally listen to vinyls, but I'm debating with myself if I should buy into one of them hifi-streaming-services out there.

Hence the DAC. Do I need one?

I mean judging by some of your posts about them it seems that the audible differences between them range from small to not at all.

I'm not interested in measurements. I want sound.

Should I buy one (WHICH ONE FOR GOD'S SAKE) or just crawl back to my cave?

I've got a Topping E30, am happy with it. Usually the real issue with mating a 2 volt output digital thingy [CD player, stand alone DAC, DAT, whatever] to an old [albeit nice] receiver is that there's usually too much output for the older gear. But that Topping DAC can have the output scaled down without loss of sound quality, and having Toslink and Coax digital ins, along with the USB in, makes it easy to hook up a CD player as well. The E30 is something like $150, streaming sounds great with it, seems like what you need.

 

[rdenney]

A DAC is handy for playing music recorded to your computer, and for playing stuff from your phone. Some stream from services (I don’t) like Tidal.

So, decide what sources would appeal to you: USB for stuff on the computer, coaxial SPDIF digital if you want to play from a CD transport without using its internal DAC, Bluetooth or Airplay (for the iPhone world) for playing from the phone.

Outputs can be line-level audio on RCA plugs.

I wire my ADC and a DAC into a tape loop. Works great. My digital stuff is on a tape loop on my old Adcom preamp.

Once you know what inputs you need, look at the master ASR table, and anything probably in the left two thirds of that chart will do fine.

I use a Topping E30, which has a remote for choosing between those inputs.

Rick “you don’t need a headphone amp or a volume control in that application” Denney

 

[digitalfrost]

Yo dudes of the x and y axis.

I love this

I normally listen to vinyls, but I'm debating with myself if I should buy into one of them hifi-streaming-services out there.

Hence the DAC. Do I need one?

That depends what device you're streaming from. Any PC with a soundcard will already contain a DAC and professional audio interfaces (fancy word for a fancy soundcard) do too. So my question would be, what do you intent to stream from?

 

[Jambo]

I was thinking my phone (iPhone) and I might buy a CD-player at one point so maybe that one too.

The Topping E30 looks nice! And it comes in silver and black, which won't look totally ridiculous next to my Marantz. It's on the top of my list!

I guess airplay is better than bluetooth, but does the Topping E30 support airplay or would I need some extra thingy to get that functionality? I'm also fine with just connecting the phone with a cable of some sorts - probably USB? - and just leave it. I'm a fan of simple life and not too many devices.

 

[Robin L]

I was thinking my phone (iPhone) and I might buy a CD-player at one point so maybe that one too.

The Topping E30 looks nice! And it comes in silver and black, which won't look totally ridiculous next to my Marantz. It's on the top of my list!

I guess airplay is better than bluetooth, but does the Topping E30 support airplay or would I need some extra thingy to get that functionality? I'm also fine with just connecting the phone with a cable of some sorts - probably USB? - and just leave it. I'm a fan of simple life and not too many devices.

If you do get a CD player, make sure it's got a Toslink or Coax digital out.

Digitalfrost makes a good point. The sound of my laptop computer through its built-in speakers is awful but the headphone output is decent. It would be worth trying the analog out of your computer, it has variable output, so it's possible to set an ideal level for the receiver, the sound might be good enough. I've owned enough CD players and vintage receivers to have encountered problems joining the two. If the receiver is 1980's or later, it probably won't overload. But yours is vintage enough that plugging in a CD player might need a little help [thus the E30].

 

[rdenney]

Airplay is supported by lots of devices, but not so many of the inexpensive DACs. But if you attach a computer to theDAC for playing streamed or ripped music, there are several Airplay simulators for Win10 that work fine. The phone and the computer need to be on the same network.

But the latest Bluetooth is really good, and even the Apple version, which isn’t the best available, will still sound as good as anything through your receiver. Just get a DAC with a Bluetooth receiver as one of the inputs. I have an ifi Zen Blue on one system, and even though the ifi DAC is only so-so, the Bluetooth receiver works well. There are better choices, but just about all of them in the hundred-buck range will be more than good enough.

Rick “thinking Bluetooth 5.0 is pretty darn good” Denney

 

[digitalfrost]

I was thinking my phone (iPhone) and I might buy a CD-player at one point so maybe that one too.

The Topping E30 looks nice! And it comes in silver and black, which won't look totally ridiculous next to my Marantz. It's on the top of my list!

I guess airplay is better than bluetooth, but does the Topping E30 support airplay or would I need some extra thingy to get that functionality? I'm also fine with just connecting the phone with a cable of some sorts - probably USB? - and just leave it. I'm a fan of simple life and not too many devices.

I'm not well versed in iPhones, if you still have one with 3.5mm jack, you can use a simple 3.5mm -> RCA cable, if not I think you'd need a "Apple Lightning to 3.5 mm headphone jack adaptor" additionally. The E30 does not support bluetooth, so you'd either need a BT/airplay receiver if you want wireless, or take a look at the Topping D50s (which has BT).

 

[Jambo]

Thanks for all your suggestions. I stumbled upon this Airport Express review by Ken Rockwell:

https://www.kenrockwell.com/apple/airport-express-audio-quality-2014.htm

I know some of you have reservations about Ken Rockwell, but what do you think? According to Mr. Rockwell it seems that I won't need anything else than the Airport Express (although I probably need the connections from the Topping E30 in order to plug the signal from the DAC into my receiver).

Is there anything to consider if I wire the Airport Express-signal through the Topping E30 and from the Topping E30 into my Marantz 2270?

To me it seems like I'm getting the best of both worlds - Airplay, DAC and the right set of connections - but it's very possible that I'm missing something.

 

[AnalogSteph]

Basically sounds sensible enough to me.

In this situation I would consider looking out for a DAC that can (realistically) double as a preamp, which is usually a bit of a weak spot in vintage receivers, and I'm pretty sure virtually all these old Marantzes can be split into pre and main, allowing them to be used as a pure power amp if need be. It tends to drive up the DAC's cost a bit since we're talking a volume control on the front and/or remote (plus, no annoying pop noises and the like!), but since all you need is unbalanced output it shouldn't be too extreme either.

 

[Jambo]

Oh boy. This is all very new to me. I thought the preamp in the Marantz 2270 was jolly good, but I reckon this is the reason why my speakers pop when I'm turning the receiver off. Haha, I've lived with it for years and just thought oh well and went on with it. What kinda DAC-Preamp-solutions are we talking about here? I think I need to see some suggestions in order for me to figure out if it's worth the extra dough or not. I might just go with my initial impulse though...

 

[Count Arthur]

I had no idea what a Marantz 2270 was, so I had to Google it.

What a beauty!

When I first got into Hi-Fi in the late 80s, these 70s receivers were desperately unfashionable, at least here in the UK. Minimalist amps were all the rage, typically with with just a power button, an input selector and a volume knob, balance and tone controls were nowhere to be seen.

 

[pozz]

Yo dudes of the x and y axis.

+1

Gave me a good chuckle.

Buy a DAC for around $100 from a company that has a decent warranty and customer support. I like JDS Labs. When you get more familiar with the ins/outs of digital audio and find that you like the streaming services or downloading music you can get into other things, like room correction and so forth.

 

[blueone]

The amplifiers in the 2270 are rather weak for 4 ohm loads, though they apparently are good for about 95w/ch into 8 ohms. They actually have lowest distortion into 16 ohm loads. I'm unfamiliar with the OP's speakers, but I suspect they are not low impedance designs. It is an inconvenient truth that compared to almost any modern equipment, the 2270 is more visual art than a great audio component. I bought a new one when I was in high school. When I saw the review in High Fidelity magazine, considered authoritative back then, I was impressed, but years later when low impedance speakers became the norm the 2270 lost its luster with me. I packed it up in the factory box and put it away until the late 1990s, when I sold for more than I paid for it new.

Here's the High Fidelity review. See page 35:

https://worldradiohistory.com/Archive-All-Audio/Archive-High-Fidelity/70s/High-Fidelity-1972-04.pdf

I agree with pozz. A $100 DAC will have more than enough performance to hide in the noise and distortion of the 2270. But I'd go for one with a volume control, because the 179 millivolt sensitivity for full power on the 2270's AUX input might be overloaded by a high-output line-level DAC.

 

[AnalogSteph]

I thought the preamp in the Marantz 2270 was jolly good, but I reckon this is the reason why my speakers pop when I'm turning the receiver off. Haha, I've lived with it for years and just thought oh well and went on with it.

Pop noise is a bit hard to avoid in any single supply circuit (such as the one in question), so that part may be normal... though you can try using a switched outlet strip to check whether it is a worn (arcing) power switch that may be giving you trouble. The preamp circuitry is more than decent by the standards of the day (as par for the course in this rather high-end model), but it'll never be the last word in noise and distortion either. The distortion part shouldn't be a major problem (I'm guessing around -80 dB H2 at rated output), while noise should be dating the unit rather more... nobody has been using 250 kOhm volume pots in decades for good reason.

But if you're saying for years and years - has the unit ever seen an overhaul in its ~45 years on this planet? Otherwise it would be filled with 45-year-old electrolytics, loads of switch and relay contacts that may appreciate cleaning, the odd known-dodgy semiconductor type (I am spotting several 2SC458s on the schematic at the very least, though apparently replaced by 2SC1775A in later production units acording to a service bulletin, and there's a VD1212 bias diode in the phonopre, a rather tricky circuit to replace transistors in I may add), and other fun stuff that goes along with old age. If you have a unit with a serial number of 50261 (US) / 62811 (Canada) or later, at least the woes known at the time should be taken care of already.

But I'd go for one with a volume control, because the 179 millivolt sensitivity for full power on the 2270's AUX input might be overloaded by a high-output line-level DAC.

AFAICS, AUX goes through switching and then straight to the volume pot, so overload should be a non-issue.

I haven't been keeping track of what DACs can realistically be used as a preamp, but I think it starts at around 250 bucks US. (Though you could go get away with 200 when going e.g. with a 2-device solution like JDS Labs Atom + Atom DAC. The stack still is small enough.) Topping D50s and DX3 Pro are some of the less expensive ones, not sure about current availability though. Several of these would include a competent headphone amplifier as well.

 

[Jambo]

What a beauty!

It is! Especially in the wood enclosure, which mine also has. The look and feel of this thing is just plain gorgeous. I mean pushing the buttons and turning the knobs. There's just something very tactile satisfying about it.

https://worldradiohistory.com/Archive-All-Audio/Archive-High-Fidelity/70s/High-Fidelity-1972-04.pdf

Thanks for this! An interesting read!

The amplifiers in the 2270 are rather weak for 4 ohm loads, though they apparently are good for about 95w/ch into 8 ohms. They actually have lowest distortion into 16 ohm loads. I'm unfamiliar with the OP's speakers, but I suspect they are not low impedance designs. It is an inconvenient truth that compared to almost any modern equipment, the 2270 is more visual art than a great audio component.

My speakers are really good. If you by any chance get to hear about these Amphion speakers nearby some day go listen. Mine are 8 ohms nominal, I believe they dip to somewhere around 6 ohms. I was aware of the weakness of the 4 ohm loads in regards to the Marantz 2270 so these babies should be an ideal partner for my receiver. I've had four sets of speakers in and out of my apartment, but listening to the Amphion Argon 3L is just bliss.

Could you elaborate on that last bit? I kinda believed in the rave reviews (yup - joke's on me) about it, but if almost any modern equipment is better I might reconsider.

Pop noise is a bit hard to avoid in any single supply circuit (such as the one in question), so that part may be normal... though you can try using a switched outlet strip to check whether it is a worn (arcing) power switch that may be giving you trouble. The preamp circuitry is more than decent by the standards of the day (as par for the course in this rather high-end model), but it'll never be the last word in noise and distortion either. The distortion part shouldn't be a major problem (I'm guessing around -80 dB H2 at rated output), while noise should be dating the unit rather more... nobody has been using 250 kOhm volume pots in decades for good reason.

But if you're saying for years and years - has the unit ever seen an overhaul in its ~45 years on this planet? Otherwise it would be filled with 45-year-old electrolytics, loads of switch and relay contacts that may appreciate cleaning, the odd known-dodgy semiconductor type (I am spotting several 2SC458s on the schematic at the very least, though apparently replaced by 2SC1775A in later production units acording to a service bulletin, and there's a VD1212 bias diode in the phonopre, a rather tricky circuit to replace transistors in I may add), and other fun stuff that goes along with old age. If you have a unit with a serial number of 50261 (US) / 62811 (Canada) or later, at least the woes known at the time should be taken care of already.

Yeah. I tell myself that one of the few things I'm good at is to acknowledge when I'm not good at things. I did know about all the wear and tear these blasts from the past have been through. That's why I bought my Marantz from a very reputable dealer here in my country (Denmark). They are specialists in bringing this old stuff back to life and up to standards again. I bought it three years ago so it should be performing perfectly.

In terms of this noise and distortion talk... I kinda thought that any distortion below 1% THD wouldn't be audible and since the Marantz 2270 is measured at 0.3% THD I believed this was fine.

I haven't been keeping track of what DACs can realistically be used as a preamp, but I think it starts at around 250 bucks US. (Though you could go get away with 200 when going e.g. with a 2-device solution like JDS Labs Atom + Atom DAC. The stack still is small enough.) Topping D50s and DX3 Pro are some of the less expensive ones, not sure about current availability though. Several of these would include a competent headphone amplifier as well.

Thanks for this advice! I will look into the options mentioned.

 

[HiFidFan]

My 'vintage' office set-up is:

iMac-->(USB)-->Schiit Modi3+ -->(RCA)-->Kenwood KR4070 AUX input

Admittedly, I specifically chose the Modi (silver) because of its minimalist design / toggle switches. It blends in better with the vintage/analog vibe IMHO. No LCD screens wanted for this particular system. Bonus, the Modi3+ is $99 and measures excellent.

 

[Jambo]

room correction

OMG, my brain!

 

[blueone]

Could you elaborate on that last bit? I kinda believed in the rave reviews (yup - joke's on me) about it, but if almost any modern equipment is better I might reconsider.

All I meant by that quip was that modern audio equipment, especially in the form of a good/pre-amp DAC and one of the more reasonably priced 100w/ch or better amps (Class D or Class AB work) will probably out-perform the 2270 in every measurable way. If the 86db SNR is accurate, that's actually pretty good considering this is a 1970s unit, however it's not even CD quality. The 2270 amp section is weak for most modern speakers that dip below 4 ohms (and usually right in the bass octaves, where the power is needed) and is not really comparable to modern amps. On the other hand, virtually nothing costing less than thousands of dollars will have the visual and tactile qualities of the 2270.

I do understand the attraction of these vintage units. In the 1990s I picked up an absolutely mint Crown CX822 7.5/15ips tape deck, complete with wooden case, at an estate sale. It was that guy's pride and joy. Compared to even the DAT units of the 90s, the CX822 made no technical sense whatsoever. On the other hand, I wanted of those decks since I was a teenager, so cost be damned. I even sent it to an ex-Crown factory tech for a tune-up at a silly cost. I loved recording on that thing, hiss and all. I kept it until I ran out of Ampex 456, and then sold it to a friend for more than I paid for it in about 2001. Now my Tascam handheld digital thing is technically far superior, but nothing beats spinning 10.5 inch reels to make me smile.

I also have a mint Marantz FM tuner with a scope I forgot the model number of sitting in a factory box somewhere in some closet. I'm sure it doesn't sound as good as MP3-128, and I haven't even powered it up in over six years, but I can't bring myself to sell it. So I do get the attraction.

 

[BDWoody]

It is! Especially in the wood enclosure, which mine also has. The look and feel of this thing is just plain gorgeous. I mean pushing the buttons and turning the knobs. There's just something very tactile satisfying about it.

I do understand the attraction of these vintage units.

Absolutely!

Very nice Marantz. I have an older Luxman Preamp that has all the appropriately luxurious buttons, switches and knobs (plus both MM and MC phono inputs)and it's the one I probably listen to/through the most, even though it's not part of my 'best' system.
It is a sensual hobby, and I enjoy that system in a different way than the others.