Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Nick Tam on November 12, 2012, 04:16:46 AM
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Okay so this isn't really going to be a complete guide but just some impressions, I gave up rolling the 6AS7s so I looked into rolling in some different tubes for the driver side, and my 6SN7s finally arrived. I don't have many tubes with me for input side so I'll just briefly summarize how each tube type sounds.
Bear in mind that the 12BH7, E80CC and 6SN7 draws double the current of the 12AU7 so it would be a good choice to have the Speedball upgrade beforehand!
12AU7/ECC82: Nothing wrong with these but average. the 12AU7 doesn't quite stand out to the rest and is at the bottom of the hierarchy. Exceptions to this bunch are the Tesla ECC802S, Raytheon Windmill 5814A and Telefunken ECC82. From my experience, bigger tube = more air, bigger soundstage. Technicalities wise, The Tesla ECC802S is actually very capable. However, it is only one of the many good value tube amongst the E80CC and 12BH7
Telefunken ECC802S/Bugle Boy 7316: For what they're worth, the Crack is not worthy of these ultra rare tubes.
12BH7: More musical and better micro detail in general. Slightly more air but ever so slightly. Rare Sylvanias or RCAs are very refined and are oozing with micro detail and dynamic range. Brimars or Tung Sol/CBS-Hytron with long curved plates are also good but rarer than RCA and Sylvania, not superior but different tonality. The other 12BH7 such as GE and grey plate RCAs are not as good and you're better off with a premium 12AU7 instead.
Philips Goldpin E80CC/6085 (Also labeled as Valvo, Telefunken, Haltron, Siemens, and early Tungsram): Very musical and full bodied in the mid ranges. Perhaps slightly thin on the highs but a very enjoyable tube with its weighty lows. There's also a foil getter version which exhibits far better dynamic range at a higher premium.
Tungsram Nickel Pins E80CC (Also labeled as Siemens): Very dynamic and linear. My reference "Hifi" tube. Slight bass rolloff but otherwise a fantastic tube. May not be for everyone due to its neutrality but the microdetail and instrument separation is as clear as day. However, this tube is very prone to sibilance on badly recorded tracks (your experience may differ). There is also an extremely rare silver plate and silver foil-D getter version of the Tungsram but I've never had my hands on one as they are extremely rare.
6SN7: Basically something like the 12BH7 BUT comparatively more "vintage" in musicality. Perhaps not superior in sonics and technicalities but the music becomes so involving that it's a far better listen than the others. Sylvania VT231 or Tung Sol Mouse Ears are a good premium.
Sylvania 6SN7W, GEC/Marconi/Brimar CV1988/B65, Tung Sol VT-231/6SN7 Round Plates: The premium tubes of the 6SN7 family throws in technicalities, air and transparency to the mix. Far more dynamic and detailed. However, not worth throwing into the Crack. Regardless of which of these tubes mentioned at $150+ per piece the Crack will not do it justice. (It probably would if you had some good headphones like the HD800) but otherwise, I think to use this in the Crack would be an over-expenditure.
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Thanks for this post! You describe what I heard as I rolled in 12au7, and 12bh7's. I don't have any 6sn7's but I settled on a NOS Tung-sol 12bh7 and I here just what you described but was not able to say.
Pat
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I think it's Doc B who is a fan of the 12AU7's possibilities. I have a bunch including variants (6189, 5814 etc). I've got some GE 5814's, a Silvertone labeled Amperex and some Philips (Herleen) that are sweet in Crack. I think there is a 6189 in the mix somewhere as well. And, I havent gotten through all of my 12AU7 types yet. I change it up between these tubes and a couple 12BH7's just for variety's sake and enjoy them all. YMMV of course.
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I assume you are using some sort of adapter to allow you to use the 6SN7s? What kind of adapter is it? I have a 6SN7 (tube) to 6DE7 (socket) adapter from my WA6. Can I use that?
Any advice is greatly appreciated!
Best regards,
Adam
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How important (if at all) is it that the two triodes in the driver tube are matched?
Best regards,
Adam
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How important (if at all) is it that the two triodes in the driver tube are matched?
This is not essential to proper operation, as long as they both have enough emission to get the plate voltage down to ~80V +/- 10%, the circuit will operate. Gain matching might be nice, but the variance of triode-to-triode gain on 12AU7's isn't that large IMO.
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Any reason to be concerned by a tube where they measure 11.3 vs. 14.6ma respectively?
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It's hard to say much about those readings, because they are just currents. If a tester is measuring tube currents and new/good starts at 12mA and peaks out at 15mA, then the 11.3mA reading might be suspicious.
If the tester specifies new/good to start at 8mA and end at 20mA, your readings look great!
The best way to measure a tube is to stick it in the Crack and measure the voltages at 1/5, listen to the amp for noise and distortion, and potentially put a 60Hz signal into the input and measure the AC voltage at pins 1/5. This will give more reliable results than any tube tester I am aware of.
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It's hard to say much about those readings, because they are just currents. If a tester is measuring tube currents and new/good starts at 12mA and peaks out at 15mA, then the 11.3mA reading might be suspicious.
If the tester specifies new/good to start at 8mA and end at 20mA, your readings look great!
The best way to measure a tube is to stick it in the Crack and measure the voltages at 1/5, listen to the amp for noise and distortion, and potentially put a 60Hz signal into the input and measure the AC voltage at pins 1/5. This will give more reliable results than any tube tester I am aware of.
Hi Paul! Do you mean pins 1/6 instead of 1/5?
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1 and 5 feed each of the triode plates in the driver tube, so those are where you'd want to look.
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PB had a LONG day, wrestling with the BeePre - he may be a little punchy.
4 and 5 are the heater ends; 1 and 6 are the plates. 2 and 7 are the grids, 3 and 8 are the cathodes, 9 is the heater centertap.
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By 1 and 5, I mean terminals 1 and 5, not tube socket pins 1 and 5.
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nt
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Look on ebay. I've bought and sold many different tubes there.
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There are plenty on eBay... this forum isn't usually the place for classified ads.
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I was hoping to avoid ebay. Anyway, I deleted my posts above on this matter.
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Has anyone tried one of the Psvane 12AU7s or CV181s/6SN7s (using a 6SN7 adapter)? If so, what are your impressions?
Best regards,
Adam
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I think the overwhelming consensus about Psvane tubes is negative. For $75, you can get a whole pile of nice old stock 12AU7's, and listening impressions of the Psvane tubes have not been super positive either.
Heck, a used Telefunken or Mullard 12AU7 can be had for $30-40 per tube.
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Thanks, that's good to know. To be perfectly honest with you, I haven't found that tube rolling has made a huge difference in the sound of the Crack, and in any case, it seems to sound good with everything I have tried so far...
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Adam,
When you find the tube that floats your boat you will know it! I'll say I have liked the Mullard 12AU7 variant, CV4007. But you may not find it as pleasing. It is a personal taste kind of thing. Same as rolling output caps.
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I currently have the stock 12AU7, a Brimar 12BH7, a Tungsram E80CC and a 6SN7 adapter with various 6SN7s (but haven't tried all of them yet). I also have RCA 6AS7G, Bendix 6080WB with solid graphite plates, Tung-Sol 5998, Chatham 2399, Sylvania 7236, Sylvania Gold Brand 6080, Russian 6N5S and a G.E.C. 6AS7G on the way*. And some other 6080 as well (can't remember off-hand).
Part of my problem is that A/B-ing tubes feels almost impossible to me. I listen to the amp with a given set of tubes (after letting the tubes warm up first), then turn of the amp, wait 5-10 minutes for the tubes to cool, then plug in the new tubes, wait for them to warm up, then listen to music again. The differences made by the tubes are subtle enough that it is tough to really get a sense of how they compare when there is 15 minutes in between. So far I seem to like the 5998s best, but I don't really have a preference on the driver tubes yet...
Best,
Adam
* The G.E.C. 6AS7Gs are being sent from the Ukraine. They were supposed to be delivered in 7 days. That was 11 days ago. According to the online tracking system, the tubes are still sitting in Kiev. When I asked why, I was told that the delay was because a major Ukrainian airline (Aerosvit), which was supposed to be the carrier, went bankrupt. Grrrrrrrrrrrrrrrrrr..........................
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The differences made by the tubes are subtle enough that it is tough to really get a sense of how they compare when there is 15 minutes in between.
Sounds like you need a second Crack ;)
Just kidding, enjoy the listening!
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Paul,
You jest, but I was actually thinking the same thing... ;D
Best,
Adam
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I've been away for a long time... but as far as I am concerned, and mentioned many times, the tubes you use ultimately are dictated by your wallet. For one, I've long given up the 421A and GEC 6AS7G hunting. The TS5998 has enough technicalities for the job. Likewise for the input side tube. You may very well throw in a TFK 12AU7, Foil getter E80CC or even a round plate square mica TS 6SN7. At the end of the day, those tubes are better off in a higher end setup than the training shoe Crack. I just settled with the TS5998 and a nice affordable Sylvania foil 6SN7. Sometimes TS mouseears 6SN7 and graphite column 6080WBs into the mix. Spending more $$$ worth on NOS tubes worth more the Crack for that minute improvement just seems pointless as the Crack won't do rare NOS tubes justice. Not unless every single part in the Crack has been replaced with some fancy highend aftermarket stuff less the power supply that makes the Crack the utmost best OTL amp that would leave you flabbergasted if you tried to drive the HD800 with anything else.
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"...a higher end setup than the training shoe Crack..."
When used with the HD800s, what is better than the Crack? This is a serious question. I've tried an awful lot of amps, including high-end amps, without finding better. The three candidates that spring to mind as potential candidates are the Eddie Current Zana Deux SE and possibly the Cavalli Audio Liquid Fire or Liquid Glass.
The Zana Deux sells for $2,200. The Liquid Glass is on sale for $3,500. The Liquid Fire isn't available right now. Mind you I'm not even sure that any of these is a better match than the Crack for the HD800s - I simply haven't tried them, so I can't say.
What else do you consider better than the Crack when used with the HD800s?
Best regards,
Adam
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I should add that after building the Crack + Speedball and testing it until I was confident that what I heard was real, I sold my Woo Audio WA22, fully-balanced Beta 22, HiFiMAN EF-6 and several other amps. Given what I saved by selling those amps, even after spending freely on tubes for the Crack I still have thousands of dollars in extra cash left over. And I haven't regretted selling those amps for a minute. Not because the Crack is cheaper, but because it is better, at least when used with my HD800s.
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. . . mentioned many times, the tubes you use ultimately are dictated by your wallet. . . .
Amen Brother! I never bought the Telefunken top of the line for my FP 2. I did spend $50 for a pair of CV4003s. I might do better soon.
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I should add that after building the Crack + Speedball and testing it until I was confident that what I heard was real, I sold my Woo Audio WA22, fully-balanced Beta 22, HiFiMAN EF-6 and several other amps. Given what I saved by selling those amps, even after spending freely on tubes for the Crack I still have thousands of dollars in extra cash left over. And I haven't regretted selling those amps for a minute. Not because the Crack is cheaper, but because it is better, at least when used with my HD800s.
Well I was only making an assumption that there are many more higher end setups and I would honestly believe that there must be something in the higher echelon that justifies the extra spending. But since you've been there, then there is nothing else to be said if the Crack is the best OTL for the HD800.
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Certainly the decision of whether the expenditure is worth it is ultimately up to the individual who spends the money. I have been at both extremes and in between, and I can't say that I found "you get what you pay for" applies very consistently in the audio business.
Do I think we could make a better headphone amp than Crack? Yes, but it would have to cost more. Do I think we could make a more successful headphone amp than Crack? Not sure.
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Just got my crack ,& with my Hd800's,I am totally amazed
I've been at it for the last 7 hours,and ever piece of music I have ranging from Brahms,beethoven,to light jazz & acoustic guitar ,sound incredible
Grainger...I'm also interested in getting the Mullards.
Can you you please tel me what the difference is between the CV4007 & the CV2984 ?
Not that familiar with tubes for this amp,but after some reading,did order a Tung-Sol 5998 today,at,what I feel is a good price.
Any help/suggestions on a Mullard-lie tube will e greatly appreciated
Thanks
Mike