L0rdGwyn's DIY Audio
Feb 2, 2021 at 11:17 AM Post #2,056 of 2,574

Galapac

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I'll go out on a limb here and say that the Darkvoice is a great sounding little amp....for $200. Perfect? Assault on the state-of-the-art? Superbly engineered with premium parts? The stuff audiophile dreams are made of? Nope, none of that. It's simply a nice sounding amp for $200. I love Schiit's Vali 2, which at $150 is another great sounding little amp for the money (IMO). The Darkvoice definitely puts more "tube" on the plate than the Vali, and it's hotter and has some hum issues and coughs and farts with low impedance 'phones and all but....it's $200. Fun to play with, and if you totally blow it to pieces you're out $200, which is less than some of us have paid for a single tube. :smile: On the budget side of HP amps the Vali is a much better choice for low impedance 'phones as its power output increases as the 'phone impedance decreases. Exactly the opposite for the OTL Darkvoice. I wouldn't even consider using 'phones with less than 150 ohms impedance with it, at least in its stock form.
If it wasn't for the Dark Voice I probably would not have tried tube amps so it's a nice gateway drug. :)
 
Feb 2, 2021 at 12:34 PM Post #2,057 of 2,574

Xcalibur255

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Speaking of power, what's the condition of the AC receptacle(s) your components are plugged into? Are they relatively new with good clamping pressure? Or....not exactly?
I don't think I have any issues on that front. The PC frontend is new, which is definitely contributing something to the soup as well. I'm slowly becoming convinced that there is no such thing as bitperfect with PC playback. All of these hardware direct bit-perfect output methods should sound the same and they don't. Settings that should have no effect whatosever on the sound, do.

I'm too old to fight with this stuff anymore. I just want it to work. :p
 
Feb 2, 2021 at 2:25 PM Post #2,059 of 2,574

JazzVinyl

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Here is kind of what I am thinking for the revamped Darkvoice 336SE circuit.

First off, the power supply will be Maida regulated, meaning all of the CRCRC-CRC caps and resistors can be completely removed, which will free up space for the PCBs that will be going in. This will allow us to increase the available B+ voltage to around 175V while obeying the dropout voltage of the regulator.

Any guess on the cost of the LG'ing of the DV336?
 
Feb 2, 2021 at 3:41 PM Post #2,061 of 2,574

L0rdGwyn

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Yeah. It seems to be a good value.

I like the simplicity of both the Crack and the Darkvoice.
Correct me if I'm wrong here, but I think these are basically iterations of the Aren van Waarde project (itself based on an older Rudy van Stratum schematic).

A basic topology of 2 double triodes with a 6922 (or an Octal) for input stage and a 6AS7G as a CF.
Simple as can be, no feedback, single-ended stuff.
Power supply follows suit.

So, i guess simplicity does the trick in this case and when built with quality parts, this design can really sing.

Actually, I just finished a project using a relevant PCB that found online.
Didn't want to go all out with point to point soldering so I ended up adapting it a bit to my modifications following the same proposition.

I have to say that my experience so far with this basic, no-frills design is very positive.
Compared with my other DIY tube amp with somewhat similar design but an SRPP for signal stage I think this one takes the cake.

Here it is waiting to be finalised.
20210202_094525.jpg

20210202_094558.jpg


Crucial points soundwise are mainly the capacitor bank in series to the output and the power supply (both filaments and anode power).
As usual problem with any kind of mods, the problem is fitting them in a tight space when you have to use a certain enclosure.

Looks great, nice job! I'm curious if the Aren van Waarde schematic is the first true iteration of the 6AS7G cathode follower headphone amp, it certainly took off.
 
Feb 2, 2021 at 3:48 PM Post #2,062 of 2,574

L0rdGwyn

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Any guess on the cost of the LG'ing of the DV336?

Don't have a number just yet, right now I am getting ready to do the mods as sort of a proof of concept. The gyrator loads are not expensive, the major cost comes with the power supply regulator. The regulator I am using on the first go-around is not my IP, so another might need to be substituted at a later date. Once I've nailed down the first mods, will need to see how I can make it more cost-effective. Another concern is the complexity of implementing the power supply regulator. Not sure how it will all pan out yet, but I've thought maybe it would be simpler if I just did for Head-Fiers rather than sending them down a path messing around with 200VDC.
 
Feb 2, 2021 at 3:55 PM Post #2,063 of 2,574

L0rdGwyn

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...and has some hum issues and coughs and farts with low impedance 'phones and all...

I really think the hum issue stems from two places: 1) the heaters are not center tapped 2) the heater windings are not twisted. Even with all of the other mods aside, fixing this should be a very simple task that anyone can do. I just need to pull out the main PCB to see exactly what has been done. Then everyone can remove the electrolytic bypass caps they added on :)
 
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Feb 2, 2021 at 4:03 PM Post #2,064 of 2,574

bcowen

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Don't have a number just yet, right now I am getting ready to do the mods as sort of a proof of concept. The gyrator loads are not expensive, the major cost comes with the power supply regulator. The regulator I am using on the first go-around is not my IP, so another might need to be substituted at a later date. Once I've nailed down the first mods, will need to see how I can make it more cost-effective. Another concern is the complexity of implementing the power supply regulator. Not sure how it will all pan out yet, but I've thought maybe it would be simpler if I just did for Head-Fiers rather than sending them down a path messing around with 200VDC.

I eat 200vdc for breakfast. Give us something to be worried about. LOL!!
 
Feb 2, 2021 at 4:08 PM Post #2,065 of 2,574

L0rdGwyn

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I eat 200vdc for breakfast. Give us something to be worried about. LOL!!

Yeah I mean for the experienced, not an impressive voltage, but for someone trying to take this on who just learned to solder and use a DMM, might be more of an issue lol. I would need to write-up step-by-step instructions with photos, which probably means modding a second DarkVoice.
 
Feb 2, 2021 at 4:09 PM Post #2,066 of 2,574

bcowen

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I don't think I have any issues on that front. The PC frontend is new, which is definitely contributing something to the soup as well. I'm slowly becoming convinced that there is no such thing as bitperfect with PC playback. All of these hardware direct bit-perfect output methods should sound the same and they don't. Settings that should have no effect whatosever on the sound, do.

I'm too old to fight with this stuff anymore. I just want it to work. :p

I get 'ya. I'm pretty much the same way with expectations. What DAC do you have and how are you feeding it from the PC? If via USB, that's evil personified without some external remediation. Schiit's (discontinued) EITR worked wonders for me prior to their introduction of the Unison USB interface. That in itself works wonders, and is now even included in their least expensive DAC for $99. Not trying to be a Schiit fanboy here, just that whatever they did with the Unison thing works magically on a USB signal.
 
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Feb 2, 2021 at 4:14 PM Post #2,067 of 2,574

bcowen

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Yeah I mean for the experienced, not an impressive voltage, but for someone trying to take this on who just learned to solder and use a DMM, might be more of an issue lol. I would need to write-up step-by-step instructions with photos, which probably means modding a second DarkVoice.

I have one I can send you. Only somewhat mangled inside. :laughing: Seriously, if you need a second one at some point I'd be most happy to send you mine. I've replaced the RCA jacks and input wiring, the volume pot, replaced the metal films with Rikens and added the bypass caps on the 6SN7 cathodes, but haven't killed it beyond that at this point.
 
Feb 2, 2021 at 5:07 PM Post #2,068 of 2,574

Xcalibur255

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I get 'ya. I'm pretty much the same way with expectations. What DAC do you have and how are you feeding it from the PC? If via USB, that's evil personified without some external remediation. Schiit's (discontinued) EITR worked wonders for me prior to their introduction of the Unison USB interface. That in itself works wonders, and is now even included in their least expensive DAC for $99. Not trying to be a Schiit fanboy here, just that whatever they did with the Unison thing works magically on a USB signal.
DAC is an Yggdrasil, and yep it's USB. I'm well aware of the reputation but it's necessary. I used it on the old PC too, primarily because solutions that would have offered a coaxial or AES output always required manually changing sampling rates in the soundcard's driver control panel and ASIO over USB eliminated that hassle. This new computer, however, I built as a mini-ITX which means it has no PCI expansion slots. I couldn't put a soundcard in it even if I wanted to.

I honestly didn't have an issue with how USB sounded before, which makes me wonder if the 5V supply in this new PC is somehow dirtier or not regulated as well as it was in the old computer. I used a top of the line Seasonic SGX power supply so it wasn't for lack of trying.

My Yggy is still using Gen5 USB, I never got around to doing a Unison upgrade. It was upgraded from Gen 2 to Gen 5 (or was it 3 to 5...?) when it got the analog2 upgrade and that got it more or less to a place where I was content with it at the time.
 
Feb 2, 2021 at 5:22 PM Post #2,069 of 2,574

Xcalibur255

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Thinking about this more I suspect the Unison upgrade is well worth doing, but I have kind of been hoping that a Yggy 2 announcement lands and I can just jump right onto that boat. I know Jason is pretty vocal about supporting the platform for a long time to justify the investment, but I think we're what 6 years into Yggy now so they have to at least be thinking about their options for a follow-on product by now.
 

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