Darkvoice 336i & 336SE Tuberolling PartII
Apr 12, 2018 at 11:10 PM Post #1,502 of 14,501
What's with this hum with the Russian made Tung-Sol 6SN7?
I've used this tube in several amps and it's as quiet as any tube I possess then, after reading this thread, I tried two in DV and both hummed loudly in both channels. There must be some bad synergy or something else going on, and then it apparently goes with 'burn-in'-so what magic alchemy is going on here?. Weird and spooky.

It's some kind of tube voodoo. I followed a suggestion to burn my Russian Tung-Sol for 72 hours and the hum disappeared right on schedule.
 
Apr 13, 2018 at 4:58 AM Post #1,503 of 14,501
mindhead 1,
I bought s/hand Beyer DT 990 Premium cans ( like new) and I think they have oodles more detail than the Senn 600.The top end can be bright on some material but this is a well known factor, you either like them or you don't, very polarised opinions here. The Beyers show that some modding will definitely benefit the D/V sound. The output caps are crucial to the sound, the better the tubes you use the more it exposes the 'thinness' of the stock amp.
 
Apr 13, 2018 at 5:45 AM Post #1,504 of 14,501
This must be the best thread to ask a favour - I really object to getting screwed on shipping/postage costs - there is a seller on ebay.com - icerope 3434, who has a lot of Tung Sol 7236 tubes for sale, red,black and white labels. The black and white labels are @ $34.95 or make an offer. For posting inside the USA $6, to France, where I live it's a whopping $24.60 + import charges @ $11.65.

Any import to the EU from a private individual is tax free if the value is below €45/US$ 55.50. I've put an offer in @ $29 on a white label tube , he's got lots of them BTW. He charges $1 for an extra tube - does anyone want to try one of these, splitting the postage inside the USA and send one onto me, declared honestly as secondhand computer tube using USPS Standard International or which ever is cheapest (no insurance) - I would be obliged, will pay in advance using Paypal.
 
Apr 13, 2018 at 1:48 PM Post #1,505 of 14,501
Apr 14, 2018 at 12:54 PM Post #1,507 of 14,501
It seems like there is few new DV 336SE owners so I decide to go over few small details in regards to this amp,hopefully this will save you some time and money down the road ,this is base on my own opinion and result of multiple testings
-DV 336SE won't benefit much from modding but if you "must" then I would recommend simple Fitz mod (hum)
-Best thing you can do and see biggest improvement is running dedicated DAC (not DAC/amp ) via decent RCA cables
This is crucial and will get rid of all the distortion /interference and hum-some tubes need burn in time
Note:
if you have no other choice but have it connected to DAC/amp and want to get rid of that interference-distortion,etc then getting rid of power ground it should help in a big way but I wouldn't recommend it for obvious reason

Tubes (based on my own preference/natural sounding )-rule of thumb, I use my DAC as reference point ;
Power tube -not as important as the driver (little guy) some would say but I never found pear shaped tube that would set the stage for SS sound , for me Good 7236 is the way to go ,this tubes are very dynamic with full and well controlled low end but they are notorious for loose particles (solder) and slightly grainy highs since most you can find are used and abused,I bought crap load of Cetron and TS 7236 back in the days and could only keep one of each ,I wouldn't touch white label 7236 with 6 foot pole
If you prefer more laid-back with drop of syrup on top sound then the best sounding one I have tested and previously my go to tube on BH Crack was GEC Hammersmith 5998 (hard to find) or TS 5998,I never had any luck with Chatham 5998 and never tested famous WE 421A

Driver tube -make or brake kinda deal
it's all here ,this thread is like national treasure in case someone missed it
https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/

Upgrading my daily SS set up give me good opportunity to play with DV336 SE again the end results was very surprising ,my tube amp sounds Very close to Audio-gd R2R11/LCD-2.2 ,I'm very happy camper :) and this is very budget friendly
Chain;
PC=>USB Hub (good interference dumpers)=>cheap audio USB cable (2x ferrite chokes)=> old Schiit Modi 24/96 (USB powered )=>RAMM Audio S600 RCA cables=> main event DV 336SE=>HD 650

Tubes used ;
Power -TS 421A (NOS $ 90.00)-more air ,low end is almost the same as 7236 but mids slightly up front , no grain extended highs
Driver-Arcturus 6SN7GT ( $6.00) got lucky with this one ,similar sound to 6SN7W but slightly better separation

Other drivers tested



Cheers

Edit ;Topping D50 have my name on it so I will be swapping Modi soon since it doesn't support DSD
 
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Apr 14, 2018 at 5:55 PM Post #1,508 of 14,501
spacequeen - you use digital, I use vinyl. Tonight I was listening to the real 1970s Reggae played on a Jap DD Kenwood KD 990/AT 33EV MC/discrete MC phono stag. The D/V and Beyer DT 990 premium cans were great, the Reggae bass was the best I have heard. I don't agree that the Fitz mod is the only one worth doing. I removed the 6SN7 (pins 3 & 6) cathode resistors and replaced with LEDS, this leads to much better steadying voltage - you can hear the difference. This was suggested on another forum as was disconnecting the Line Out altogether, which I shall do still leaving me the choice to re-connect if I decide to use the pre-amp function. It is said to lift a veil, making the D/V much closer to the B/Crack.

Tonight I used the Tung SOL RP 6F8G as driver, the forerunner of the 6SN7 version, the other is the 1578, great detail,transparency, not a hint of harshness at the top, nothing beats the TS RP for emotion. The 1578 works beautifully with classical, especially orchestral.Thanks for the craic on the white label 7236.

With all equipment - never forget that everything you hear comes through the signal wiring - signal wiring is ignored by 99%. The beauty of the D/V is that it is a very simple circuit and it is point-to-point, changing the signal wiring from input to pot and signal hard wiring isn't hard or expensive.
 
Apr 14, 2018 at 6:45 PM Post #1,509 of 14,501
I was just watching one of the Z reviews and he's describing the noise I mention in my previous post (@ around 14min mark ) ,that finger tapping noise in one of the channels is clear sign that one of his tubes is microphonic ,as you can see there is another amp stage in the chain


Edit :there shouldn't be anything creeping out from the background all the way to 70~80% on the volume knob
 
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Apr 21, 2018 at 6:19 AM Post #1,512 of 14,501
There may well be another take on the hum problem - far to much gain. The pot is 250K - so why not attenuate this. Take a look at www.goldpt.com/mods.html. This provides all the info on what resistors to use for different levels of attenuation on different value pots.

It couldn't be simpler - just desolder the signal and earth input wires and solder the appropriate value resistors in series. If your not sure what level of attenuation you want just buy a few sets, PRP are very good and not expensive.

The Philips (Mullard) 6080 arrived yesterday, used with the 6F8G TS RP I don't find it lush at all, voices stand out and far more revealing using this combo.
 
Apr 23, 2018 at 2:59 PM Post #1,514 of 14,501
Can those who either have a multi-meter and/or can download a resistor colour code chart let me know what value the pins 1 & 4 (6SN7 driver tube) resistors are. I've already taken out the resistors on pins 3 & 6 and replaced with LEDS, definite improvement in detail and space. Second I removed the hot melt glue to to desolder connections to the pre-amp output - another improvement in detail - voices take on a 3D audio state, like they are right beside you in the flesh. If you don't make these simple mods, you don't know what you are missing.

I asked what the value of pins 1 & 4 are because I removed mine which are 1M and replaced with Z foil 100K - a definite NO-NO. Why did I do this mod,because I have seen layouts showing 100K. My previous mods really opened up the D/V and heard voices as never before. Using 100K shrunk the whole soundstage.

So if those resistors in your D/Vs are 100K then you have to change them for 1M, the difference isn't subtle.

Another simple mod - how to get more useable steps/levels on your stepped att/ pot - www.goldpt.com/mods.html. It only involves desoldering the input wiring and soldering on resistors to signal and earth - you don't have to resolder underneath the pot . You can see lots of visuals of the D/V online and someone has kindly labelled the pot PCB, so it's easy to identify the various solder points.
 
Apr 24, 2018 at 12:06 PM Post #1,515 of 14,501
So, the SE is back up for grabs on Massdrop : https://www.massdrop.com/buy/dark-voice-366se
I was wondering if I should save up for a Schiit Lyr 3 or get one of these baby's... I know there is a 300$ price gap, but i'm willing to save up and wait if needed....
 

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