Darkvoice SE Advice, what tubes and where to buy?

So I’ve been running my Darkvoice SE solo since I recently switched to a SDAC-B from my O2/ODAC combo and am waiting till November for THX789. I tried using the SMSL SAP VI, but the sound felt claustrophobic, so I decided a couple months maining a tube shouldn’t be too bad (despite using Plainars on it too) with my HD 650. I was trying to look into tubes to alter the Darkvoice a bit, but I’m just not seeing a place to buy that seems reliable.

First off, what size tubes does the Darkvoice use and second where to you buy tubes for it?

PS I feel really bad, since I’ve had a Darkvoice for years, even though it sound really nice.!

The DV fits 6SN7 and 6AS7 Tubes.

Ebay is gonna be your best friend for tubes purchases, just be attentive and check seller feedback to make sure everything is good.

My personal favorite combo on the DV is Tung-Sol 7236 + Tung-Sol 6SN7GTB (or more recently I’ve really been enjoying my Hytron JAN-CHY-6SN7GT).

I would probably recommend getting the TS 7236 and then rolling 6SN7 tubes until you find one that you really like. Then eventually you can roll to a different 6AS7 tube, no need to overwhelm yourself at the beginning. Tube rolling is all about what “flavor” you want to enjoy today, you’ll get used to constantly changing sounds depending on what mood you’re feeling at the time.

Edit; Also if you have the time maybe do some reading here; https://www.head-fi.org/threads/darkvoice-336i-336se-tuberolling-partii.348833/ Probably the most useful place for tube rolling the DV on the web, lots of good literature to research in there :wink:

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I have and love my Darkvoice, and just ordered a La Figaro to start my tube rolling obsession over again. I am more or less a tube noob, so I am 100% sure that others will have better advice with data to back it up with, but I ended up settling with the following from Tube Depot:

So 6as7g 2 Sovtek 6AS7G Power Vacuum Tube (1) @ $58.95 = $58.95
Ts 6sn7gt nobox Tung-Sol 6SN7GTB New Prod. Preamp Vacuum Tube (1) @ $23.95 = $23.95

I made this choice based on online reviews and went with some of the cheaper options I could find for both to see what I thought. There was a good amount of hum from them which died down after a 72 hour burn in, but there is an audible buzz when I first power it on prior to playing music. If it persists during playback I don’t hear it. I love the darkvoice because its a cheap way to test the water for a powerful tube amp. If this was my endgame I’d probably invest more, but I am saving that for the La Figaro now. With that I am looking at an approximately $500-$600 investment above the stock tubes and I think that will be where I stop, although I can’t be certain. More than the fact that I just flat out think tubes are cool, I love the idea that different combos make the amp seem like a completely different product. While I’ve seen several $1000 + tube amps, I think the Darkvoice, and especially La Figaro should be all you need. You should especially like the combo with the Sennheisers, as I am eyeing HD800s to pair with the La Figaro when I wouldn’t have had interest in those headphones otherwise. Unless you only like solid state sound, I think every Sennheiser I’ve heard sounds better running off a tube amp. For me anyway

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I like using RCA power tubes 6080 or 6as7 will work. and for pre tubes I like using tungsol 6sn7 tubes. you can buy them on ebay or on sites like vivatubes.com. NOS tubes from the 50s are my favourite, although some new russian tubes are good too.

I read every thread I could find on tube rolling for my Darkvoice, (much work) and made several purchases to try the past few months. In the end the nicest combination of tubes I found was purchased from theTubeDepot in Canada, absolutely wonderful and helpful folks to deal with, excellent customer service and experience for me.https://www.thetubestore.com/

The combination I like most is a bit spendy but worth every dollar (IMHO), these 2 tubes together manage both clarity and a rich sound. There is “tubbiness” to the sound without any “mushiness” in the varied genre’s of music I have thrown at them. While rolling different tubes I found particular varieties worked better w/some styles of music more than others. This particular combination has been the best performer across blues, jazz, vintage rock, hip-hop, rap, techno, classical etc. and they perform well at “high volume” without distorting the bottom end or bringing harshness into the top end. Sorry this is the best I can do to bring a sense of description to the sound. If I were Zeos, I would be grunting in happiness and joy.
Anyway, use:https://www.thetubestore.com/shuguang-natural-sound-cv181-t
https://www.thetubestore.com/winged-c-6h13c-6as7g

As always YMMV, good luck, and remember the smaller 6SN7 front tube may require a 3 or 4 day burn in period if it has hum when you first plug it in, mine did and works perfectly and quietly since. I wish I could take credit for this combo but i can’t, I was fortunate to read about it somewhere and noted the combo on a sticky but I can’t remember where to give credit to the original roller…

I forgot to add, i do enjoy the combo w/ varied headphones but my “go to” for the Darkvoice is my Massdrop HD 6XX Sennheiser’s,

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Hi ;
Just want to pass on some info I have on the DV336Se headphone amp.
The 6sn7 tubes that I have come across can create a 60hz hum in the amp ( this will be present when No music is playing and volume is turned All the way Down. ).
My experience tells me that the power filter caps are bad or failing. I went ahead and replaced all 3 caps ( some which had been damaged in the build ) this was due to the way the Caps are held in place via a clamping style device . The bad news is it did not solve this problem of the 60hz hum.
The next thing I looked at was the tube itself I have noticed that the original 6sn7 and my Shangung tubes had clear tops with the Mercury on the bottom to one side the part of the tube known as the getter was also at the bottom.
Please don’t worry about all the technical stuff I have enclosed in this post I do it for those who might be interested, to make it easy I am staying away from any 6sn7 tube that has a suffix of GTA or GTB for now. Stay with the Clear top 6sn7,6sn7g and 6sn7gt series
Tubes be it nos or new production and all should be fine.
For what It’s worth I’ve replaced the 6as7 coke bottle style tube with a GE JAN series I’ve got from www. Partsexpress.com for about $12.00 that is really great and not as large as the original.
All in All, as someone who has been in this HP,Preamp It Is VERY well built And a STEAL for $200.00 !

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For power tubes, you can use 6AS7, 7236, 6080, 5998, Russian 6H13C, Chinese 6N5S tubes.

For driver tubes, you can use 6SN7, VT-231, 5962, Russian 6H8C, Chinese 6N8P tubes.

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thanks. i got on the tubestore and picked up a couple. I followed the link Nick_Mimi left above. I picked up a Tung sol 6sn7gtb and a Winged C. Lets see what happens.

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I think the Mullard 6080, RCA JAN-CRC 6AS7g and Tung Sol 7236 are some of the best affordable power tubes.

As far as driver tubes, Ken Rad VT-231 (Black Glass), RCA JAN-CRC VT-231 (Grey Glass), RCA 5692 and Tung Sol 6SN7WGTA (brown base) were my favorites.

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I know this is a bit late but the amp also has 2 more filter caps per side of the preamp tube (Those 4 that extend out and feed the individual side of the Driver tube @ 220UF Capacitance which is a bit more optimal for the tube I guess). Those can also affect hum I guess but unlikely to be honest since if the first three caps didn’t fix the issue in filtering, it’s unlikely those would do any better seeing how they’d receive a pretty well filtered DC at that point.

For the Hum issue I see alot of people say to use Bypass Caps (Search Hum-Fitz Mod) on the Cathodes in order to fix this, but a better solution would be to remove the transformer and order a correctly made one for US voltages (I did this, don’t use Cathode bypass caps and my amp is dead quiet with 99% of tubes).

I’m going to assume you’re in the U.S., in which case you have 120V in your Outlets, since the transformer has a primary of 110V instead of 120, all voltages going out the secondary will be a bit larger proportionately, giving you about 7V on the heaters instead of ~6.3V and at a current of .6 Amps either way (correct me if I’m wrong though since my understanding is that the heaters determine the current and you simply have to give it the voltage it wants, so be it at 4 or 8 volts, the current amount wouldn’t really change unless the voltage dips lower than the current rating, and I guess same thing with the Plates but I suppose that’s why CCS or Plate resistors are used as well, well that and to lower voltages to the plates too proportionately for a specific operating point, but I guess max current available would change with a resistor vs CCS, idk getting off topic).

I recommend getting the transformer ordered from the original manufacturer here:
https://www.hdoofactory.com/

They have an online chat service and tends to be quick enough on the shipping and manufacturing (~10 days). True this is the more extreme option but it’s probably going to be the most effective method. Other than that you can do the previously mentioned Cathode Bypass cap trick (Hum-Fitz Mod) to reduce noise overall, albeit you get a bit of gain due to this and the capacitor quality is rather important here, maybe go with an ELNA capacitor.

Also forgot to give you the Transformer Specs just in case:
120 VA (Just a hair over the originals Maximum Rating for a bit less heat when using heavier consumption tubes)
Primary 120V
Secondary 135V - 0.7 Amp
Secondary 6.3V - 3.6 Amp (This way you can also use .9 Amp Preamp tubes safely, ergo why the VA was increased a touch)

Also Ask for a Center-tap grounding since it helps with noise a touch although it doesn’t really matter much other wise unless you get confused as to why the transformer would suddenly be missing a green/yellow wire. (Honestly I remember using a multi-meter to test what the green/yellow wire does but it doesn’t seem to be connected to any winding from what I could tell, so I gotta assume it’s connected to the Core itself or something, again, idk, although online sources say that wire color is reserved for grounding center-taps, again, don’t quote me on this).

If you’re worried though you can always ask them for a Darkvoice 336SE Transformer @ 120V primary and they’ll get you the exact specs of a normal Dark Voice transformer but for 120V primary.

You can also make the heaters DC but that’s a bit more complex (More of a space issue although it can be done, also you need to drop voltage, you know, RMS vs DC, DC tends to be Peak Voltages so it goes up a bit, so use resistors if you do this, but then again, it’s be easier to just use resistors in general to drop the heater rail voltages since DC doesn’t really affect indirectly heated Cathodes.

OK so to sum up (TL;DR):
Hum-Fitz Mod: Easiest Choice, Get Good Capacitors (16V-24V @ 110 uF/220 uF <— capacitance number affects gain, higher means more). This won’t actually decrease Heater Voltages and that can lead to a lower expected lifespan for the tubes due to overheat/over-specification.

Transformer Swap: A Bit harder and a bit more expensive, but getting experimental with Transformer Values can lead to a larger variety of tube possibilities due to Min/Maxing Certain Values/ Increasing VA and increasing Current limit of the Heater Rails for more tube options. If not you can always order the original Transformer with 120V Primary Specified.

DC Rails: DC will remove any hum since DC is at 0Hz, but you’d need to build a rectification circuit as well as a CRC Smoothing Section in order to clean the DC and make sure the Resistor lowers the DC to 6.3V again. After that DC has no other noticeable benefits since the tubes are Indirectly heated (Would be great in Tubes like 2A3 and 300B Triodes of yore but the Darkvoice can’t use them, since the Transformer Theoretically couldn’t give out the Plate Voltages, well maybe it can but then you’d need 2 Tubes in the amp or another Darkvoice, which while sounds fun, it’d be better to build one from scratch using 2A3/300B). Downside to DC rectification however is a new point for RF interference as well as the quality/speed of the rectification determined by the quality of the Diodes. This sucks especially in such a tight enclosure.

Resistors On AC: This also helps and is WAY easier than DC rectification but make sure the resistances are right (You need to know how much voltage the secondary is actually outputting, so either use a multi meter or maybe a bit of math using transformer widings and stuff) as well as heat rating (Watts), also you need 2 resistors on each rail end.

Oh and if you’re already inside the Amp, maybe take the time and Twist the Heater Wires together, get some 16 or 18 gauge wire and make twisted heaters. If somehow you do all of this (Especially the Transformer Swap) and the Amp STILL makes Hums/Noise, then the tubes are probably micro-phonic (Especially NOS tubes that haven’t been maintained in a good state of use or mistreated)

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