Hello, I just joined, primarily for the audiophile products. Looking at purchasing the NHT C3 speakers for our new living room. Space is about 15 feet wide by 33 long and they will fire long ways. Space is just for general listening, music room with all equipment is downstairs, so hoping they will fill it with sound nicely. Cheers.
Mar 18, 2024
One of my favorite combinations is the tung Sol 7236 with the Sylvania vt231. The warmth of the 7236 is a nice balance to the clean sparking sound of the vt231. The 7236 also sounds great with a raytheon vt231 (the Raytheon has a bit more punch than the Sylvania).
I also like the pairing of a Chatham or Tung Sol 6as7g with a warm sounding driver tube like a Ken rad (vt231) or national union 6sn7gt.
Since you are in Europe (right?), You may be able to get a hold of a Brimar cv1988 driver tube (British tube equivalent of 6sn7) for a decent price. The Brimar sound is absolutely magical. It tends to be a warm tube, but it sounds amazing with a 7236. It's difficult to describe the sound of a Brimar since it is so unique. My father listened to my Darkvoice with the Brimar and 7236 and simply described the sound as absolutely beautiful which I think best describes its sound. I often find myself smiling when listening to it. I've seen quite a few for sale from British sellers. You may want to check eBay UK to see if there are affordable ones ($50 to $100 depending on condition would be good)
My issue is that after things have warmed up a bit, say 10 minutes, I lose the right channel completely. It will come back if I swap tubes and let it cool, but within 10-15 minutes I lose the right channel again. Once or twice I've not had it from the very start, so I don't know if it's a pin/solder/short issue or what. No other tubes do this, so I know it's not my sockets. Everything has been cleaned and de-oxd, so it's not corrosion either. Working with the seller to swap for a different tube, but figured I'd ask and see if there was something else I might be missing, because I'd hate to find out it was something simple on my end after I'd already returned it.
Do have another question for you, this time on power tubes. I got one each of a TS 7236 and a Syl JAN-5998A. The Syl is circa 1980 and the TS is not dated, but it can't be any older than that (even though they were both sold as NOS). I know you have both of these tubes so can you tell me if your DV (and those tubes) run hot? I mean hot enough that you can't touch the tubes without a towel and the DV itself gets pretty toasty - way beyond the normal warm that I've experienced before with the stock tube, an SED 'winged-C' 6H13C, or an RCA 6AS7G. Seller said he runs a pair in his Little Dot and it gets very hot, too, but I think I recall reading somewhere that the 5998 (and perhaps the 7236) doubles the gain and I don't want to fry the transformer. Thoughts?
Just a clarification about one of your tubes: the syl 5998A is NOT the 5998 that gets all of the positive praise. The 5998A is a VERY different tube (inferior to my ears). Tung Sol (or Chatham) was the only company that made the 5998. The 7236 is very similar to the 5998--a little less warm, but has an energy that I sometimes prefer to the 5998. Another way to get a 5998 is to keep an eye out for a 2399 tube (identical to 5998 but given a different number for some reason. these usually fly under the radar since most people just look for the 5998...I got a NOS 2399 for about $35 recently). I've attached a pic that shows a 5998 and a 2399 (note they look identical). The giveaway are the "domino" plates (the black plates inside the tube with 6 dimples in a domino pattern). BTW, Chatham Electronics and Tung Sol are the same brand.
The 7236 and 5998 DO run hot. And yes they increase the gain. They are completely safe with the darkvoice. Here's a link to the electrical data for the 5998: http://www.tubebooks.org/tubedata/5998_TS.PDF. I'm definitely not an expert on the electronics behind tubes/tube amps (my next quest), but I THINK the data to look at is the heater voltage rating for the tube and compare it to the max allowed by the amp. Based on the data I've found online (plus the endless forums that recommend use of the 5998 and/or 7236), these tubes will work just fine in the DV. I pretty much exclusively use a 7236 or 5998 and run them for hours at a time on a regular basis with no problems (yet, knock on wood). Just make sure you don't touch it or have flammable things near it (or little children....I'm constantly knocking my children's hands from trying to touch the tubes)
I'll run some temps on the different tubes so I have a better idea of the heat differences I mentioned.
I think I'll try to return the TS to the seller... it makes some popping noises at random that can't be good for the amp/cans and definitely not my ears. The Syl sounds pretty good to me, other than the heat aspect, so I will keep that one (and look for the other one you mentioned).
Thanks for the pics and suggestions on the other tubes... I'd not seen or heard of the domino plates, but I did get that Raytheon VT-231 in the mail over the weekend here at work so am going to give that a listen when I get home.
Cheers!
6as7g thread: https://www.head-fi.org/threads/for-6as7g-tube-rollers-here.410326/ DV thread with tube rolling discussion of powertubes: https://www.head-fi.org/threads/darkvoice-336-336i-tuberolling-tubes.193214/page-6
I'm cutting an pasting tube info for 6as7g variants from the beginning of that 6as7g thread (I think this will ease your mind): tried to put together some 6AS7G equivalents with notes (from my personal experience). of course, the usual brand/re-label disclaimers apply. So no need which one is better. The goal here is just to list the main equivalents that may work in your amp's circuit. Did I miss any equivalents?
6080 - low gain @ 2- great vocals, wide soundstaging
7236 - medium gain - great bass, fast and dynamic. Almost SS sounding
5998A - medium gain in straight bottle. Plate construction like 6AS7.
5998 - medium gain at 5, full-bodied sound, same current load as 6AS7
421A - same as 5998 but with matched plates/sections
6AS7G - low gain, the standard tube for most, plentiful
6AS7GA - low gain, like the standard 6AS7G in striaght bottle
6520 - premium 6SA7G, sometimes with 5998 plates
6H13 - russian 6AS7G equivalent. nothing magical with these
ECC230 - european 6AS7G equivalent. haven't seen one in person
6528 - equiv to 5998 but very high gain at 9, twice the current load. Make sure you amp can handle it
6336 - like 6528 but low gain at 2, still twice current load. Make sure you amp can handle it
Yeah, Head-Fi is a great source... I've been a member there for about 6 years now (ID: TigreNegrito) and that's one place I do a lot of my research and get info (granted you have to sift through a lot of chatter). I've read the tube-rolling threads, but those are mostly geared to the output tubes, so thanks for posting the link to the power tubes. I knew there was one, I just didn't bookmark it at the time and forgot what site I read that info on, but the stuff you cut and pasted must be from where I read about the gain changes with different tubes.
I found a few more you can look over, but they are geared towards internal mods. I'm not yet at the stage where I'll start taking stuff out and soldering newer stuff in, but it's interesting to read:
http://www.just-hifi.com/Custom-Edition-Darkvoice-THA336FM-arrived-56K-warning_10059904.html This is a breakdown of all the mods Fitz did beyond the original cathode bypass caps, but unfortunately the photos are all gone, since he posted this 12 years ago! http://rockgrotto.proboards.com/thread/2734/darkvoice-336-kiss-mods This one actually has some pics so you can see the progress.
http://forum.polkaudio.com/discussion/145315/yaqin-cd3-darkvoice-336se-mods-coupling-caps Just found this one and haven't read through it all yet, but I think it has some photos, just a few of which are the DV mods.
For now, the Syl 5998A is pairing nicely with the Raytheon VT-231 and really cut back on the bass, making for a much better experience listening to classical music with the 6xx (most of the other combos were too heavy in the bass region to listen longer than half an hour or so).
It feels like its running cooler, but thermometer readings at the top mica of the power tube are 300F, top mica of output tube 185F and the top of the case around the tubes about 100F. I'll swap back in some of my other tubes and take measurements tomorrow to see the difference, but as I said, it feels cooler overall than it did when I first tried the 5998A this past weekend.
Cheers!