Salas DCG3 preamp (line & headphone)

I am not a headphone fanatic but I listen a lot on headphones + DCG3 while working. But given the choice I prefer speakers in almost every way.

Massdrop is fine, but the shipping and delays can take a long time. But it is a legitimate, reputable company.

I like AKG's because they are most "speaker-like". But other people find them too diffused and too open and airy. The Senn HD series always feels like a true "middle of the road" headphone to me with the Hifiman sound on one side of the spectrum and the AKG sound on the other.

But I also enjoy a pair of Grados for rock music from time to time.
 
Thanks. I agree with you about speakers versus headphones. At least, listening to my little PX-100s, they get fatiguing after a while. This is one of the reasons I don't see myself investing in high-end phones. What I really need is to upgrade my speakers. I also don't like being tied down with a cord. I mainly built the DCG3 because I think it's boss-cool.

It seems like all the action is in wireless cans nowadays, anyway. From a convenience standpoint, wireless is brilliant. I'm seriously bothered by glued-in batteries, though. That's a total show-stopper for me. More to the point, wireless headphones render the whole concept of a headphone amplifier moot, evidently.

The nice thing about this headphone amp is it's also a first-rate system line amp. So I could just as well forego the headphone purchase and be happy as a clam using the DCG3 that way.

I'm a sucker for trivial aesthetic details. The XLR connector on the front totally says "pro audio" to me. I love it, and want to have something to plug in there, LOL.

-Henry
 
Thanks. I agree with you about speakers versus headphones. At least, listening to my little PX-100s, they get fatiguing after a while. This is one of the reasons I don't see myself investing in high-end phones. What I really need is to upgrade my speakers. I also don't like being tied down with a cord. I mainly built the DCG3 because I think it's boss-cool.

It seems like all the action is in wireless cans nowadays, anyway. From a convenience standpoint, wireless is brilliant. I'm seriously bothered by glued-in batteries, though. That's a total show-stopper for me. More to the point, wireless headphones render the whole concept of a headphone amplifier moot, evidently.

The nice thing about this headphone amp is it's also a first-rate system line amp. So I could just as well forego the headphone purchase and be happy as a clam using the DCG3 that way.

I'm a sucker for trivial aesthetic details. The XLR connector on the front totally says "pro audio" to me. I love it, and want to have something to plug in there, LOL.

-Henry

I also feel like the "house sound" of headphone manufacturers varies wildly. Much more than speakers. Maybe this is due to the shape of people's ears, or the fact that there are multiple competing driver technologies in headphones but I feel like headphone makers have more liberty to make what they think sounds good vs. speaker companies. Speaker companies stick to the chart, so to speak. Speakers are pretty much all trying to do the same thing with varying levels of success depending on size and 2-ways vs 3 ways, etc. Headphones are all over the map in what they are trying to accomplish.

So, it makes recommending a headphone a very difficult decision. What's good for me may not be good for you.
 
You make a very good point. All my effort reading reviews hasn't really helped much. You would think the elimination of room interaction, the low power requirement, and the straightforward geometry would make it easier, not harder, to design headphones.

On the other hand, the external structure of the ears is critical to perception, and headphones screw with much of that.

I have just about enough credit card reward points to pay for a set of HD600s. I had the courage to ask my wife if I could use the points and she agreed. Amazing! If I don't use them, my 26 year-old daughter will probably steal them to buy makeup.

I keep telling my wife to lock my daughter out of the account, but you get to a point in life where you value your relationship with your kids more than they value their relationship with you, so you try not to antagonize them... :)

I see you're in Seattle. That's where my daughter lives, too, FWIW. I'm on the east coast and don't get to see her often.

-Henry
 
I have akg 7xx which is the massdrop version of the 702. I don’t feel like they have weak bass...I also have akg 272 closed backs which have weaker bass. I feel like the bass is deep but not dramatic on akg 702. If you want bass impact then I would recommend a planar. I also have grado 125 which have more bass impact but can be too bright and don’t have an open soundstage.

Akg is a more open soundstage but the sounds are less immediate. The sounds are coming from a greater distance away from your ears. Some of the planar headphones and beyers sound more immediate and impactful but also sound more “in your head” in my opinion.

Sennheisers are kind of a happy medium between the two. Many classical listeners choose sennheisers.

But like I said, headphones are a pretty personal thing. Hard to make a recommendation. Best to try some out first, which might be difficult to do given the times we are living in.

And Iam a born and raised Seattleite. Although I live in the suburbs about 10 miles north of Seattle. It’s a nice place but not necessarily nice this time of year.
 
Thanks for the report. I play classical piano (like, with my fingers) and listen to a lot of recorded piano as well. Bass slam isn't a priority for me, but I want to hear the fundamentals of the piano lower register. My ears are not pristine, sadly, and I'm sensitive (in a bad way) to sibilance.

I got excited about the AKGs, then turned off by certain negative reviews. Same for Beyerdynamic Amiron Home, then Audeze LCD-1. Now I'm reading about the Hifiman Sundara. The latter seems very promising, but questionable QC and overall somewhat wonky build are turn-offs. The HD600 seems better for my purposes than the HD650 and I may be getting these, but for some reason I find the notion of the Sennheisers to be so conventional that it makes me want to do something different just to be contrary.

This is actually quite maddening! Not, as you say, like buying speakers where just about everyone is targeting a very similar sound target. Anyway, this is all a "first world problem" so I will continue to enjoy the shopping process. I'm in no hurry.

I was in Seattle for two weeks last September. I'm glad I brought a surgical-grade N95 mask with me, and not because of COVID...

Thanks again for your reply.

-Henry
 
Well, I found a pair of K702s on Amazon for $229 and I ordered them. I also bought a Topping E30 DAC ($149) to replace my old DIY AMB Labs Gamma 2. The E30 is for use with an RPi running Roon.

After reading all these reviews, it seems like every middle-tier headphone is a compromise one way or another. I'm intrigued by the AKG premise and expect they will give me a taste of true hi-fi. At this price, they're cheap enough that I don't have to fret about wasting my money if I don't like them. And if I get bored with headphone listening, I can move the DCG3 to the main system -- where it's literally the best upgrade I've made in years.

Spending 50-100% more, you're still in the middle tier but the stakes feel a lot higher. What amazes me is even at the $1000 level the reviews are still very mixed. You would expect at $1700, the HD800S would be universally praised, but no.

So, with luck I will have these next week and I will report back how I like the AKGs.

-Henry
 
Let us know how you like the AKGs. I think you will like them. Good fit for the DCG3 I think. I have a friend who owns pretty much every high end headphone and has many headphone amps. He said akg 7xx via the salas amp was about as good as you can get if you enjoy the AKG-type sound.

But headphones are relatively cheap and the Salas amp is pretty indifferent to what it is driving (it can drive low and high impedance headphones) so if headphones are a priority for you it’s nice to have some options for different genres of music, etc.
 
I have tried BC-327-40 2 times

but prefer in my setup BC560

so try both and listen carefully,,,,BC 327 is more mellow here

Hi, long time lurker here.
The last year the dcg3 has been on "display" and not used. Remembered it as extremely good sounding. However when I took the plunge and changed to bc327 I really felt a decrease in sound quality. Especially I felt the bass got "weaker" in a way og less PRAT (as many say it).

Anyone else has the same experience?

Thinking of changing back to bc550/560
 
diyAudio Chief Moderator
Joined 2002
Paid Member
With high Hfe picked and matched BC327-40s in the current mirror (Q1 Q2) I feel there is more "phrasing" in the bass and sweeter tone in the highs. But preference might be system synergy dependent and/or music genres dependent. Before going back to BC560Cs I would recommend you try few different U1 JFET input type OP-AMPS also.
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Only very high input impedance op-amps are doing a most proper job in this position. Because the input filter to the DC servo shows 1MEG source impedance. In other words don't try with bipolar input types like the 5532, but with JFET input or FET CMOS input types. Like OPA2134, ADA4625-2, OPA1656 etc.
 
diyAudio Chief Moderator
Joined 2002
Paid Member
OP275 is hybrid "BiFet" with low noise low offset spec, thus usable, but still not like Fet for input bias current. Exchanging between AD823 OPA2134 OP275 can give you an idea of how to best combine the signature for what type of favorite BCxxx current mirror transistors in your system.
 
Thanks again.
I actually think I have a small problem with this. Very low signal going through. Full volume and it is very low. Measured with AWG in and scope. No wonder it feels "a bit lifeless" ;)
Perhaps a grounding fault or floating? Is there a good grounding scheme for this preamp?
 
Last edited:
diyAudio Chief Moderator
Joined 2002
Paid Member
Typical grounding schemes all work for strong signal despite if one can be preferable for lowest hum. But on a previously well working build first thing would be to check that PSU voltages are correct and signal cable screw connectors are tight. Also look for cold joints. If some transistors are on pin sockets maybe they lost good contact?