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PostPosted: Thu Oct 04, 2018 8:45 pm 
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Joined: Mon May 19, 2014 7:40 pm
Posts: 77
Location: Newcastle, ON, CA
Is it possible to categorize the effects of changing the 6922 vs 6sn7 vs 5u4 vs Kt88 tubes?

Current speakers are Totem Hawks and Forests. The amp has all stock EH tubes. Honestly, I'm not blown away vs the Musical Fidelity M6i so I'm not sure if this means I like the MF just as much. I prefer the Triode setting and 8ohm taps for the most part but at times the Hawks sound better in ultralinear. I don't think power is an issue as the volume is plenty loud with the knob at half way.

I've enjoyed the Hawks and in purchasing the Forests I've gained a much fuller, cleaner sound but the soundstage is much narrower. I also find the Hawks are much more detailed and have a more "airy" sounding vocals. Fustratingly, at times it is this "holographic" sound that can sound artificial.

I would be extremely happy if I could get more detail (eg fine nuances in cymbol work), a slightly more airy sounding vocals and a wider soundstage from the Forests by tube rolling.

Where would be a good place to start? I'm not quite ready to give up on Totems yet but I wish I could combine the qualities of both the Hawks and Forests. Proac d18's have been suggested to me in the past. Nola Boxer II?

Thanks for any input.


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PostPosted: Thu Oct 04, 2018 11:53 pm 
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Joined: Sun Mar 10, 2013 6:57 pm
Posts: 201
Location: Ontario, ON, CA
I too have an sli80 as well as a Rogue cronus magnum which I also paired with totem forests.
The speaker combo with either amp was so so untill I added an equalizer, then the forests sounded better, but something was still missing. I ended up selling the totems and buying a pair of klipsche rf7ii's. Much easier to drive and the missing frequencies were back.
As nice as the forests are, two drivers versus three or more, well it's not a fair fight in a tower speaker. If your totems were bookshelves I think they would sound better with your amp.


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PostPosted: Fri Oct 05, 2018 2:54 am 
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Joined: Sun Dec 28, 2008 7:49 am
Posts: 1949
Location: Fairport Beach (in Pickering), ON, CA
I've never heard that amp but it should sound pretty good. I do have experience with the Cary Rocket 88. Me thinks some of the EH tubes could be upgraded:

6922 - buy any Amperex/Phillips. Don't go nuts on expensive variations.

6SN7 - buy the least expensive RCA or GE you can find whether New Old Stock* or used. Those two brands are abundant and sound nice. Don't waste money on expensive or rare vintage variations.

5U4 - buy the least expensive vintage brand you can find. You won't notice any difference in sound with vintage manufacture varieties as they all made their tubes to meet the required specifications. Sylvania and GE are pretty inexpensive and abundant.

KT88 - I have EH branded KT88's but have never tried them in my rebuilt/modded Dynaco Mk III's. It's a bit of a PITA to bias/balance tubes in my amps so I install and leave/check bias once in a while. I am using new production Gold Lion KT88's and am happy with them. I have to admit though, that for the cost they don't last. I don't use those amps very often, but I would say around 500 hours per pair. Maybe keep your EH KT88's for now and change the rest to find out if you get the sound you're looking for. I love my Mk III amps but they are in a fifth system so get very little use.

The Cary amp should sound pretty good with the above tubes. If not, look at your speakers and preamp. I have Alon speakers (the predecessor to NOLA) and you won't be disappoint with NOLA. Mind you none of mine are tube amp friendly unless one is running 100wpc and more! The NOLA designer (Carl) voices some of his speaker designs with tube amps, although you may want to ask what amps/system Carl is using.

*Remember, NOS means exactly what it says. It has nothing to do with age. It means a brand new example of an item which is no longer in production. A BNIB winged C tube is a NOS tube too.

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Collecting vintage tube Pilot (Pilotone) HiFi gear.


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PostPosted: Fri Oct 05, 2018 4:40 am 
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Joined: Tue Dec 07, 2004 4:18 pm
Posts: 2879
Location: GTA, ON, CA
I have a SLI-80 is a secondary system and have rolled many tubes.

The 6922 tubes are input buffers/cathode followers and are used to lower the high impedance output of the source so that it can transferred to the 6SN7 driver tubes. The tube buffer has no voltage gain, but IME, changing the tube to a high quality vintage tube had a positive effect. I use a 7308 Siemens with excellent results. These tubes have the least impact on the sound.

The 6SN7 tube are driver tubes or phase splitter tube. This takes the input signal and splits it into two identical signals (ideally) each 180 degrees out of phase with each other. These signals drive the output tubes so while one is amplifying the positive (push) going signal the other is amplifying the negative (pull). IME, these tubes have the greatest effect on the sound of the SLI-80. There are literally 100’s of high quality vintage 6SN7 tubes available for less than $100 a pair. Personally, I like the Sylvania tall bottle tubes.

The Output tubes are best matched to your speakers and your listening preference. If you have relatively high efficient speakers and like a sweet romantic sound, look toward EL34 or 6550 tubes. If your speakers require a bit more power and drive, look towards the KT88/120 family. I personally like the Gold Lion Genalex KT88 as an all-round excellent performer.

The 5U4 tube is a rectifier that is used to convert alternating current (AC), into direct current. Direct current (DC) is needed to operate all of the circuitry. Since the rectifier tube is not in the audio circuit, I was never a believer in the benefits of rolling rectifiers until I starting doing so in my tube equipment. It does make a difference. There are many excellent vintage 5U4 rectifiers available and they are not expensive. Sorry, I forgot which brand I use in my Cary but has a ST glass envelope.


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PostPosted: Wed Oct 17, 2018 3:15 pm 
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Joined: Sun Aug 18, 2013 2:43 pm
Posts: 39
Location: Edmonton, AB, CA
I have had a cary Sli-80 running a pair of forests upgraded to the cad 120s an SLP -98P to get a little more juice which did the trick. But to be honest I wish i kept the SLI-80 and just bought KT-120s saving some$$$. I notice cary amps are a total different animal with kt120 in triode the sound stage is more wider and gives better drive and dynamics. In fact the kt120s where so open i missed the small imageing of the kt-88's. So bought a match set of gold lions which sound a bite more dynamic and better bass the the stock KT-88. which I'm sticking to the gold lion KT-88's for now on. I personally have talked to Vince at Totem before about power required for the forests. He said 40watt triode pure class A power is still better then 80watts AB. As he put it the quality of each watt is more important then the quantity. Some times less is more. Anyways plan on buying a SLI-80 for my bedroom rig.


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PostPosted: Wed Oct 17, 2018 3:34 pm 
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Joined: Tue Sep 25, 2012 1:54 pm
Posts: 703
Location: Calgary, AB, CA
Totem Hawk with Gold Lion KT88 was a memorable combo, very fun sound. Sometimes I think about going back to them now that I have a better power amp (Don Sachs Kootenay 120).


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PostPosted: Wed Oct 17, 2018 4:25 pm 
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Joined: Mon Mar 24, 2008 6:55 am
Posts: 392
Location: Toronto, ON, CA
[quote="PERRLA"]Is it possible to categorize the effects of changing the 6922 vs 6sn7 vs 5u4 vs Kt88 tubes?

Current speakers are Totem Hawks and Forests. The amp has all stock EH tubes. Honestly, I'm not blown away vs the Musical Fidelity M6i so I'm not sure if this means I like the MF just as much. I prefer the Triode setting and 8ohm taps for the most part but at times the Hawks sound better in ultralinear. I don't think power is an issue as the volume is plenty loud with the knob at half way.

I've enjoyed the Hawks and in purchasing the Forests I've gained a much fuller, cleaner sound but the soundstage is much narrower. I also find the Hawks are much more detailed and have a more "airy" sounding vocals. Fustratingly, at times it is this "holographic" sound that can sound artificial.

I would be extremely happy if I could get more detail (eg fine nuances in cymbol work), a slightly more airy sounding vocals and a wider soundstage from the Forests by tube rolling.

Where would be a good place to start? I'm not quite ready to give up on Totems yet but I wish I could combine the qualities of both the Hawks and Forests. Proac d18's have been suggested to me in the past. Nola Boxer II?

Thanks for any input.

I would get the EH tubes out fast. The EH 6SN7 is a particularly bad sounding driver tube in my opinion.
You are looking for more detail, more air and a better soundstage. One output tube I have tried that brings all of those qualities to an amp is the Gold Lion KT66. You will give up a little power compared to KT88, but KT66 has the best highs and more air than any other output tube I’ve tried. Very holographic tube as well. KT66 tells it as it is with no bloat or sugar coating. Make sure you lower the bias before making the change and bring it up to whatever Cary recommends for KT66.
The 6SN7s and 6922 should be good quality NOS. Try a Sylvania for the 6SN7 (they are all pretty good but the best for drivers are the 6SN7Ws or the VT-231 or 3 hole “badboys” if you can find them). For 6922 try Amperex, Siemens or Telefunken.
Not sure if you have different output taps, but if you aren’t already try the 4 ohm taps for the Totems.
Enjoy the roll!


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PostPosted: Wed Oct 17, 2018 6:42 pm 
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Joined: Mon May 19, 2014 7:40 pm
Posts: 77
Location: Newcastle, ON, CA
Thanks for the responses guys. I picked up a pair of NOS 1958 Sylvania 6sn7gtb from fellow CAM member brf. There was an immediate improvement in the highs and detail. The previous owner of the amp told me the bias was set before storage and that it should be fine. My mistake but I took his word for it and probably listened for about 6hrs before checking myself. To my surprise they were running at 180mA! instead of the recommended 75mA. I hope this didn't shorten the tube life too much.

Anyways now set-up correctly and with the new Sylvania's the amp sounds amazing. Some songs I like ultralinear and some the triode mode. I'm pretty sure I'll be keeping the Forests now and selling the Hawks. They're still not as airy but so much improved now and I do enjoy the fuller sound. Only concern is on bass heavy songs the Forests can be a bit much for my smallish room. I haven't tried mass loading either speaker yet.

I'm looking forward to trying other tubes and can see how one can get "Cary"-ed away with tube rolling.


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PostPosted: Thu Oct 18, 2018 4:43 am 
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Joined: Tue Mar 20, 2012 11:02 am
Posts: 293
Location: Milton, ON, CA
PERRLA,

You rolled the tubes I would recommend and you chose some good ones. Enjoy the improved sound.

Audiois1st

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PostPosted: Thu Oct 18, 2018 10:49 am 
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Joined: Tue Sep 25, 2012 1:54 pm
Posts: 703
Location: Calgary, AB, CA
What's interesting is I've used this as a reference guide to what tubes I may want to purchase (namely deciding between GTBs or unobtanium NOS and if they're worthwhile). I can't say I'm a huge fan of the EH myself in my preamp but it doesn't seem to suck as much as it's portrayed here...

https://www.head-fi.org/threads/the-ref ... ad.117677/

RE: EH 6SN7

NEW STOCK – Electro-Harmonix EH6SN7 [PHOTO HERE]
[black plates, black base, black labels on glass, top getter]
● “The Electro Harmonix were the most dynamic in the MPX3 . The Bass is also the best and biggest of the three; quite detailed and tight. Midrange is also full of detail air and transparency up and down the range. Gets a little too bright in my system at times, but generally the most fun and involving tubes to listen to so far for me.” –bobjew
● “With the Electro Harmonix 6SN7's in current production, there is no need to suffer.” –Hirsch
● “They are fast-paced tubes with a bit of a heavy bass and paired with a slower driver tube the combo sounds quite nice.” –donovansmith
● “I came across a new 6SN7 tube by Electro-Harmonix and it sounds great. This tube seems to be a very good copy of the Sylvania VT231.It has killer bass and an excellent midrange and vocal performance. It warms up quickly and is not noisy or microphonic at all. It is an excellent value at $10.00 a pop. […] The build quality is high and they are very, very closely matched as tested on my tube tester. These get a "best buy" recommendation from Tuberoller. Try them before dropping big bucks on the Ken-Rads or CBS Brown or Red based tubes.” –Tuberoller
● “The biggest finding is that the Electro-Harmonix 6SN7 tube is about as good as a Syl 6SN7GTB.” –scottpaul_iu


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