Review and Measurements of DarkVoice 336SE Headphone Amp

[SIY]

Anybody here try any of the simple mods to lift the so called veil on this amp? There's a bunch out there and the two simple ones I did opened this amp up by noticeable margins. The first one I tried was just disconnecting the RCA out (I eventually just took the whole wiring out to be sure) That was a huge boost in headroom. to clean things up I then tried out the Bias LED Mod (which darkened the background even deeper)

https://www.superbestaudiofriends.org/index.php?threads/darkvoice-and-crack-mods.5621/

Uh huh.

 

[solderdude]

It went from a DarkVoice to a ClearVoice...

Did you also remove the grid stopper resistor ?
This lifts an entire heavy curtain instead of just a veil.

The stupidity of its designer(s) is mind boggling. They must have built it without even listening to it. Why didn't they apply these mods to begin with. Would have made more profit also.
You should also replace the final piece of wiring to the headphone out. Only the last few cm make the difference. Ohh.... don't forget to change the mains cord. There is a lot to be gained there as well.

 

[SIY]

The stupidity of its designer(s) is mind boggling. They must have built it without even listening to it. Why didn't they apply these mods to begin with. Would have made more profit also.

Reading through that thread was depressing- no one there seemed to know very much about tube design, but were hacking away regardless. And naturally, no validation. OTOH, one might infer that a big sales feature of this stuff was the ability to do mods for entertainment purposes without the inconvenience of having to know anything.

 

[Jkdjedi]

It went from a DarkVoice to a ClearVoice...

Did you also remove the grid stopper resistor ?
This lifts an entire heavy curtain instead of just a veil.

The stupidity of its designer(s) is mind boggling. They must have built it without even listening to it. Why didn't they apply these mods to begin with. Would have made more profit also.
You should also replace the final piece of wiring to the headphone out. Only the last few cm make the difference. Ohh.... don't forget to change the mains cord. There is a lot to be gained there as well.

I did the ones I mentioned because of the detailed pics that thread had...lol, removing grid stopper capacitor, yeah, if only I knew what that was or what it looked like. So u nds like something I'd be willing to try.

 

[SIY]

I did the ones I mentioned because of the detailed pics that thread had...lol, removing grid stopper capacitor, yeah, if only I knew what that was or what it looked like. So u nds like something I'd be willing to try.

It was tongue in cheek.

Don’t take out the gridstoppers. Don’t follow most of the “advice” on that thread.

 

[solderdude]

I wouldn't remove any grid stopper resistors myself.
On top of that, when someone doesn't know what they do or are I would suggest not playing around with tube amp circuits.
Lethal voltages in there !

 

[Jkdjedi]

I wouldn't remove any grid stopper resistors myself.
On top of that, when someone doesn't know what they do or are I would suggest not playing around with tube amp circuits.
Lethal voltages in there !

Thanks... I'll stay put then! It's sounding amazing as is with what I've done so far.

 

[JediMa]

I own a DV and I agree with the review 100%, it's a kind of a fetish amp, the retrò feeling somehow helps to forget the many flaws, but as Amrin stated with high impendance headphones It sounds good, with my Sennheiser HD600 is a very nice match and makes some music extremely enjoyable. It's not an amp for purist but it's very appealing for the ones that like to just enjoy that listening moment.

 

[amjosh]

I would really like to see the measurements with upgraded tubes. I am currently using tung sol 6SN7. I think the quality has improved, at the cost of hum though. After few days its still there. I have not done constant 48-72 hour burn in yet, may do it later. From the thread on drop.com, I am now looking at the 6080 tung sol NOS and shanguang treasure for the 6ns7. But it's a lot of dough (about $150 or so together), so waiting to hear more feedback.

 

[Veri]

I am now looking at the 6080 tung sol NOS and shanguang treasure for the 6ns7. But it's a lot of dough (about $150 or so together), so waiting to hear more feedback.

This is why tube amps are a big money sink.

 

[preload]

I’d take a cmoy over this tube amp. I believe they’re roughly from the same era too.

 

[zepplock]

I’d take a cmoy over this tube amp. I believe they’re roughly from the same era too.

Nah, darkvoice wasn't that bad. When I had it I had no hum and paired with 600ohm it sounded decent. What I mean is that music was enjoyable, no noise, no obvious distortion at listening levels.

 

[lobe67]

Hello, thanks for this great review...good to know that it has a lot of power ..but mine doesn't !
My darkvoice never worked really properly. I use it with my AKG K340 and Beyerdynamic DT150 both high impedance cans. At the beginning the hum was hudge but i came progressivly down (a bit). Then the big lamp wouldn't light up until I squeezed some connectors of the support . Now both lamps light up but is sound is still very weak. I changed both lamps but the sound remained the same accept hum that came back up!
Maybe i should change the Octal support ?

 

[Kartal]

Is it sound on the warm side or the bright side?I have a schiit vali 2 and

I am unstable between bottlehead crack 1.1 and darkvoice

 

[lobe67]

i'd say bright side for the DV but then again mine never seemed to work properly...I' go fot the bottlehead wich seems more reliable

 

[L0rdGwyn]

I am doing a total circuit overhaul of this amplifier to improve the design and also correct many of the mistakes of the original designer, just a fun DIY project for someone on Head-Fi.

These are not hocus pocus modifications, actual circuit design changes based on sound tube amplifier design. I'll post something in the DIY thread to show it off when it is done, but wanted to point something out here...

The widely reported hum issues in this amplifier can be corrected by making two circuit changes. The heaters in this amplifier are not center-tapped, the designer has grounded one leg of the heater at the power LED ground point. A virtual center-tap can be made using two 100ohm 1/2W resistors.

This improves the hum but does not eradicate it, I suspect due to significant primary-to-secondary leakage currents in the transformer which is of poor quality. The hum is present on some input tubes, not all, due to heater-to-cathode leakage. The second change that must be made to completely cure the noise issue in these tubes is to elevate the heaters above ground. I used a 220K-100K voltage divider to give the heaters a ~50VDC lift, which completely fixed the noise issue (note the B+ in my circuit is 180VDC as opposed to ~150VDC in the original design, so adjust voltage divider resistor values accordingly).

 

[dfuller]

The widely reported hum issues in this amplifier can be corrected by making two circuit changes. The heaters in this amplifier are not center-tapped, the designer has grounded one leg of the heater at the power LED ground point. A virtual center-tap can be made using two 100ohm 1/2W resistors.

That is, in a word, atrocious. Even the cheapest guitar amps I come across have a (faux) center tap on the heater circuit. A better option if you can fit it is a pot wired in between the heater leads so you can adjust for lowest possible hum.

This improves the hum but does not eradicate it, I suspect due to significant primary-to-secondary leakage currents in the transformer which is of poor quality. The hum is present on some input tubes, not all, due to heater-to-cathode leakage. The second change that must be made to completely cure the noise issue in these tubes is to elevate the heaters above ground. I used a 220K-100K voltage divider to give the heaters a ~50VDC lift, which completely fixed the noise issue (note the B+ in my circuit is 180VDC as opposed to ~150VDC in the original design, so adjust voltage divider resistor values accordingly).

This is the best option though, as it essentially "reverse biases" the diode created between the heater and cathode.

 

[L0rdGwyn]

That is, in a word, atrocious. Even the cheapest guitar amps I come across have a (faux) center tap on the heater circuit.

Yup, it is extremely amateur, this is tube amp design 101. There are other questionable decisions in the amplifier as well.

A better option if you can fit it is a pot wired in between the heater leads so you can adjust for lowest possible hum.

Right, I was on the verge of adding in a humdinger rather than the 2x 100ohm center tap, but then elevating the heaters took care of the rest, so I didn't pursue it. Will post a thread in the DIY forum showing my circuit changes shortly. It isn't really a DarkVoice anymore, but the sound is significantly better.

 

[L0rdGwyn]

Here is my circuit overhaul: https://www.audiosciencereview.com/forum/index.php?threads/darkvoice-336se-circuit-overhaul.20377/

 

[Racheski]

Did Amir ever do a teardown?