i dont think westinghouse made 6CA7–can u please post pics? im most curious what u have there.
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What do you think are the best current production vacuum tubes?
- Thread starter Jon S
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u got time to post pics all around the tube?
Lavane
Lunatic Member
I personally prefer diode rectified. Out of the 15 tube amps and preamps I have, only one preamp is tube rectified, and only three amplifiers are tube rectified.
There is no writing on the top or on the red base.
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Mybig8ohm
Active Member
I prefer a tube rectified preamp though it's certainly no deal breaker. I have it in my head that it throws a better soundstage. But It probably makes no difference lol.
I have a question about your ST35. Mine came early & I'm testing it out on my back patio test set up running with the tubes4hifi SP13.
With the JJ's in it it sounds pretty good. Fast n punchy. But this amp chassis gets hot. When the wind was blowing I could smell the heat..& all the heat seems to be coming from just the power tubes. Is this normal or the same that you experience?
any writing on the bottom of the base? if not etched into the glass, thats where philips, mullard etc put em.
Lavane
Lunatic Member
Ya it gets hot. Many people run the Dynaco and Dynakit amps without the cage. But when I added the choke and bias board it was just too ugly without the cage. I do wish there were more slots on the sides of the cage for better ventilation. I added taller feet too. The little nubs didn't leave much space underneath.
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i dont know of any european or american EL34/6CA7 that matches this. the only EL34 with that tiny single halo getter i can find is shuguang, and the micas are identical to those of older shuguang. in addition, the only EL34 i know with those mica supports is shuguang. there are several other tells. i think its shuguang.
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Mybig8ohm
Active Member
I was referring to this tubes4hifi ST35. It's housed inside their enclosed aluminum chassis with some top & side air vents.
There is some serious tube heat building up inside this thing. I'll need to ventilate it better
mine gets real hot, and i vented my chassis a bit more. i usually take the lid off.
Lavane
Lunatic Member
That's what I was going to suggest, take the top off. Maybe set a couple whisper fans on top pulling air out of the chassis, or on the bottom pushing air up through the inside of the chassis might work too?
I can see how that amp would get pretty warm inside.
The preamp I wouldn't worry about too much, signal tubes dont get as hot.
I have owned many tube components over the years and can go down many bunny trails on my experience with several different tube families. Instead, I will offer my knowledge on the end game of my tube experience. As much as I‘ve enjoyed several different tube amps, I‘ve ruled them out in the end and decided SS amps are preferred. I went through a phase where I used tube preamps (combined with SS amps) and felt this gave me some tube magic without the cost, heat, instability and anxiety related to a tube amp. Then I decided I really don’t need a preamp and preferred passive and digital solutions to attenuate unity gain line level signals.
My final tube solution is the use of a tube buffer. By far the best one on the market is the Modwright Analog Bridge. Simply an amazing component that uses a tube rectifier and two separate tube driver circuits, one for the 6SN7 tube family and one for the 6DJ8/6922/7308 family. Mine is the XLR balanced version which utilizes Lundahl transformers. Although you can roll rectifiers to get different secondary audio effects for driver tubes, I prefer a more transparent solution. I have found the only rectifier that provides the stability, accuracy and long life is the older Mullard GZ34. Stupid expensive but nothing comes close in the long run. I have owned four through the years with only one that has drifted from spec. I have gone through a dozen other rectifiers that simply could not take the same torture.
I use the 6SN7 circuit for listening to digitals sources. I have a bunch of older 6SN7 tubes that are fun to roll but they have gotten stupid expensive so I keep them in the vault for special occasions. In the end, I use EH 6SN7 tubes that measure well and maintain some stability. They are cheap enough that I keep several matched sets in standby as most every modern tube has some risk of drifting over time. I have tried several other modern 6SN7 tubes but most cost a bit more than the EH with little or no benefit to my ears. In my experience, if you can find a set of EH 6SN7 tubes that measure well and stay stable, they will perform very well for several years. True that some drift in a matter of days but they are cheap enough that I just toss them.
I tend to use the 6DJ8/6922/7308 circuit for analog sources. I have a huge collection of this family of tubes that I acquired before things got stupid expensive. I have not found any modern tubes that sonically match older options. Most don’t even come close and typically drift very fast. If I did not have my collection of these older tubes I would explore newer options as there could be some possibilities? Old Holland Amperex, 7308 PQ, Mullard Blackburn, Telefunken, miniwatt SQ, etc, all live up well to their reputations. IMHO a ‘real’ Mullard CV2493 beats them all for what I look for in this tube. I am very lucky to have bought a dozen of these in Europe many years ago from a military surplus source at a shamefully low price (I could have bought 100 unit batches!). Current prices for the CV2493 are stupid expensive with most out there of questionable origin. From what I understand the CV2493 is a really tight measuring CV2492 tube that survived a military torture test. It was mostly used in radar equipment in Eastern Europe BITD. All twelve of my tubes measure very high and all match perfectly. Not one of them has ever drifted in the 30 years I’ve used them.
My final tube solution is the use of a tube buffer. By far the best one on the market is the Modwright Analog Bridge. Simply an amazing component that uses a tube rectifier and two separate tube driver circuits, one for the 6SN7 tube family and one for the 6DJ8/6922/7308 family. Mine is the XLR balanced version which utilizes Lundahl transformers. Although you can roll rectifiers to get different secondary audio effects for driver tubes, I prefer a more transparent solution. I have found the only rectifier that provides the stability, accuracy and long life is the older Mullard GZ34. Stupid expensive but nothing comes close in the long run. I have owned four through the years with only one that has drifted from spec. I have gone through a dozen other rectifiers that simply could not take the same torture.
I use the 6SN7 circuit for listening to digitals sources. I have a bunch of older 6SN7 tubes that are fun to roll but they have gotten stupid expensive so I keep them in the vault for special occasions. In the end, I use EH 6SN7 tubes that measure well and maintain some stability. They are cheap enough that I keep several matched sets in standby as most every modern tube has some risk of drifting over time. I have tried several other modern 6SN7 tubes but most cost a bit more than the EH with little or no benefit to my ears. In my experience, if you can find a set of EH 6SN7 tubes that measure well and stay stable, they will perform very well for several years. True that some drift in a matter of days but they are cheap enough that I just toss them.
I tend to use the 6DJ8/6922/7308 circuit for analog sources. I have a huge collection of this family of tubes that I acquired before things got stupid expensive. I have not found any modern tubes that sonically match older options. Most don’t even come close and typically drift very fast. If I did not have my collection of these older tubes I would explore newer options as there could be some possibilities? Old Holland Amperex, 7308 PQ, Mullard Blackburn, Telefunken, miniwatt SQ, etc, all live up well to their reputations. IMHO a ‘real’ Mullard CV2493 beats them all for what I look for in this tube. I am very lucky to have bought a dozen of these in Europe many years ago from a military surplus source at a shamefully low price (I could have bought 100 unit batches!). Current prices for the CV2493 are stupid expensive with most out there of questionable origin. From what I understand the CV2493 is a really tight measuring CV2492 tube that survived a military torture test. It was mostly used in radar equipment in Eastern Europe BITD. All twelve of my tubes measure very high and all match perfectly. Not one of them has ever drifted in the 30 years I’ve used them.
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Mybig8ohm
Active Member
I'm going to hook this power amp into the living room today with a better set of speakers. I have a 2 fan intake/exhaust with 90° sensor I could set over the vents or just run it without the lid first. But yes, it's like an oven in there.
And yeah, that tubes4hifi Aikido circuit doesn't even get warm..cool runnings. I have quite an assortment of tube pre's to try with the el84 but the Aikido pairing on my back patio yesterday seemed nice. I ordered a quad of some 60's German (Ei tooling) power tubes from Brentjessie yesterday..cheaper than the el84m's I was about to order. And a set of 6p1p-ev for $40 bucks from a different seller.
It uses ecf80's for drivers which I have a few nice sets in that family. I like the the premiums 7643's by mullard, Valvo & I have some ecf80 & 6bl8 by Tungsram & La Radiotechnique. I actually ran Tungsram ecf80's you can get for $14 a pr on the 'bay in my ST70 & love them. These are not 6gh8 equivalents if you look at the specs but have worked well for me in my Van Alstine 70 the last 4 months. I'll have to wait & see if the tube is short lived in the ST70.
For me, after 45 years of listening testing as well as measurements, it is clear.
For output tubes, I definitely prefer the reissue Mullard KT88 with cathode bias. Extremely transparent,
natural sounding. I do run my output tubes rather easy, 440 p-k idle voltage, 29 watt plate dissipation.
The only small signal tube I use is the JJ E88cc. By far the lowest THD vs other tubes for line preamplifier
output of 2vrms. Was able to design a perceptually perfect (and natural sounding) line preamplifier,
very near perfect phono stage (with separate ps chassis), and monoblocks with separate power
transformers and B+ supplies for each stage). One negative is longevity of the tube.
Caveat: My entire system decoupling capacitors of dac (analog stages), phono stage, line preamplifier,
monoblock amps, xover speakers, use polypropylene capacitors, except the HV with poly bypass of
electrolytics, and multiple cathode bypass caps. This essentially replaces the DA of 7-10%
with DA of 0,02% for much much greater transparency and naturalness. It is, however, extremely
sensitive to parts and other qualities in design.
keep on truckin
joe
For output tubes, I definitely prefer the reissue Mullard KT88 with cathode bias. Extremely transparent,
natural sounding. I do run my output tubes rather easy, 440 p-k idle voltage, 29 watt plate dissipation.
The only small signal tube I use is the JJ E88cc. By far the lowest THD vs other tubes for line preamplifier
output of 2vrms. Was able to design a perceptually perfect (and natural sounding) line preamplifier,
very near perfect phono stage (with separate ps chassis), and monoblocks with separate power
transformers and B+ supplies for each stage). One negative is longevity of the tube.
Caveat: My entire system decoupling capacitors of dac (analog stages), phono stage, line preamplifier,
monoblock amps, xover speakers, use polypropylene capacitors, except the HV with poly bypass of
electrolytics, and multiple cathode bypass caps. This essentially replaces the DA of 7-10%
with DA of 0,02% for much much greater transparency and naturalness. It is, however, extremely
sensitive to parts and other qualities in design.
keep on truckin
joe
fantastic
I can't tell who made that tube, but that getter sure looks like Telefunken's thick ring getter style.
TConnelly
Active Member
Greetings all, I have a situation I’ve been dealing with that I think might relate to this discussion. I have a Bugera V5 Infinium 5 watt tube guitar amp. 12AX7 and EL84. The Infinium refers to their tube life monitoring system. It adjusts the power tube bias automatically as the tube ages. There is an led on the back panel that comes on and the jewel light flashes when it's out of spec. When I first got the amp. it would take about 20 seconds to warm up and produce sound. After about a year and a half I noticed that once the 20 seconds were up the jewel light would then blink for another 20 seconds. So I got two new tubes from Antique Electronic supply. Both were from J J. After that it was back to normal.
Then recently after another year and a half or so it started doing it again. I decided to try Tung Sol this time. But this time with the Tung Sol EL84 It would take almost a full minute to start blinking and then almost another full minute before it would stop blinking and produce sound. So I ordered another from J J. This one worked exactly like the worn out J J that it replaced. Except I found that the new one from J J would not produce any sound until it stopped blinking. But the old J J would produce sound after the normal warm up time. So now I'm really confused. Do I buy yet another tube to see what happens?
So my question now is 'how likely is it that I've gotten two defective tubes back to back? Both defective in different ways? And secondly, if so is it more likely to get good ones if you buy them in say a matched pair? I'm not sure now whether this amp has a problem. Am I demonstrating the very definition of insanity? Asking the same question over and over expecting a different answer?
Sorry for the long post. Thank you for any thoughts you might have if you've gotten this far.
Cheers.............Todd
Then recently after another year and a half or so it started doing it again. I decided to try Tung Sol this time. But this time with the Tung Sol EL84 It would take almost a full minute to start blinking and then almost another full minute before it would stop blinking and produce sound. So I ordered another from J J. This one worked exactly like the worn out J J that it replaced. Except I found that the new one from J J would not produce any sound until it stopped blinking. But the old J J would produce sound after the normal warm up time. So now I'm really confused. Do I buy yet another tube to see what happens?
So my question now is 'how likely is it that I've gotten two defective tubes back to back? Both defective in different ways? And secondly, if so is it more likely to get good ones if you buy them in say a matched pair? I'm not sure now whether this amp has a problem. Am I demonstrating the very definition of insanity? Asking the same question over and over expecting a different answer?
Sorry for the long post. Thank you for any thoughts you might have if you've gotten this far.
Cheers.............Todd
Mybig8ohm
Active Member
Tubes are finicky. It wouldn't surprise me if you received 2 bad tubes back to back but that would be some serious bad luck. It happens though.
Could be the auto-bias. I would email Bugera & tell them about your situation. Ask them about their bias system & what would make the amp act this way? See what they recommend as far as tubes & minimum measurements. But yeah, I would definitely send them an email..