tube fanatic
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Posts posted by tube fanatic
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Doing a complete tuner section alignment on a receiver like this is not something that should be attempted if you don't have the experience; it's much too easy to mess things up! At the very least you will need an AM sweep generator, an FM stereo signal generator with calibrated output, and an oscilloscope. For educational purposes, it would be better to find an old solid state mono tuner and play around with that. There are probably some online tutorials on the procedure to be followed. In any event, good luck, and don't hesitate to ask if you need any more advice.
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I turn on mono, close my eyes, and move the balance until it sounds as though the singer is coming from right in front of me. Then I open my eyes, and see where the balance knob is. I am pretty sure my left and right ear hearing are the same, but I aint no spring chicken at 49.
Doing what "mustang guy" suggests is the easiest way to set it. There are many variables at play here- room acoustics, slight efficiency differences between the speakers (try switching them between the 2 channels and see if you now have to swing the balance control to favor the right channel), differences in power output between the 2 amp channels, and your own ears. Remember also that potentiometers are rarely balanced to provide exactly the same resistance between the midpoint of rotation and the ends. And ganged potentiometers (as used for the volume control of stereo amps) never allow exact tracking between the 2 channels. So, at a given setting, one channel may be providing more signal than the other. Is this something that has developed now, or has it always been that way? And does it happen with any source that you're listening to, or just with a particular one? The other factor, which many never consider, is whether you have a large gob of wax in your ear canal which is attenuating the level. I'm my ENT doc's favorite patient as I come in 2-3 times/year to have everything cleaned out. I can actually tell when it's time as my high frequency response decreases when the buildup gets to a certain point.
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im also curious about the quality of chinese tube amps available.
this one in particular interested me
http://www.musicalparadise.ca/mp/index.php?main_page=product_info&cPath=6&products_id=75
anyone here have any experience with this amp?
These forum members may be able to help you:
http://community.klipsch.com/forums/p/154485/1628040.aspx#1628040
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"Once you start replacing the caps in the tuner sections, a complete realignment will be necessary"
Changing dried out electrolytics will not affect the alignment.
I didn't look at the schematic for this unit, but if the multiplex section uses discrete components, replacing the electrolytics with those having different values/characteristics can throw things off. Some say it can't happen, but in my experience it has.
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Some of the Yaqin amps have gotten favorable reviews, and for the money they sure are pretty! For the same money, it may be possible to have the Pioneer amp restored after which it should be quite nice. The fact that you are hearing crackling and hum suggests that there are problems other than tubes. Continuing to use the amp without knowing what is going on could set you up for failure of parts which could be very costly to replace. What model is it? The advantage of mono amps over most stereo amps is that they allow the greatest channel separation, limited only by the source. This generally allows a wider and deeper sound stage, if that is important to you. In addition, many modern stereo tube amps do not have a balance control. Since room acoustics, recording imbalances, and differences between our ears often necessitate a somewhat different volume level for each speaker, not having the ability to adjust that can also affect soundstaging and imaging.
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I'm holding to the original values as close as possible, only varying the voltage rating when I have to. So far I have replaced 38 caps on the two main "power boards" but there are at least another 30 - 40 in other places. I am also replacing the 4 power transistors as one is bad.
Should I "soldier" on with my soldering or let them go until they actually fail (if that is in my lifetime) ?
How about replacing the caps on the phono stage, any risk of changing the sound for the better or worse?
I am still enjoying the project, I just don't want to change this unit any more from original than is necessary or prudent.
Once you start replacing the caps in the tuner sections, a complete realignment will be necessary. So, if you don't have the required test equipment and know how to do this, I'd leave well enough alone. Regarding the phono section, depending on how much capacitor values have changed, the resulting sound after replacement can be different. Whether it will be pleasing or not is indeterminate. The same can be said for the preamp and amp sections also. But, since you're already committed in that part of the circuit, I'd certainly finish the job there.
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Calibrating the meter is the least of the problem. Keep in mind that VU meters usually have a damped movement which will present kind of an averaged reading as opposed to showing the peaks. Ideally, you want to use a driver circuit for the meter which will put a very high impedance across the amp's output so as to have no effect on the sound. Are you sure that you really want to bother doing this???
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Here's some info which will help you get started on your "quest!"
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Thanks to everybody for all the great replies and advice.
Would running a solid state pre amp affect the sound coming out of a 45 set amplifier in any way?
Or would it totally destroy the 45 set magic sound and make it sound solid state doing this?
It's hard to determine what effect it would have. You would need to try it yourself. Remember that your sources are, I assume, all solid state anyway. Why not go with an integrated tube amp so you don't need a preamp at all?
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Unless you are talking about extremely thin wire, like a #22 or 24, and have a long run, there's no advantage at all. How far from your amp are the speakers? If less than 15-20 feet, some #16 lamp cord is all you need.
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Newer technology has allowed the size of capacitors to be greatly reduced. Whatever you do, make sure that the rated working voltage of the replacements is at least the same as what's in there now. Also, go for the highest ripple current rating for the power supply electrolytic caps that you can find.
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Does the amp have both 4 and 8 ohm taps on the output transformers? The 63s probably drop down into the 3.5-4 ohm range somewhere in the mid bass area so you may have to try each to determine which sounds best. How about some more details about the amp?
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H I would love to think so, but, I am looking for stellar imagaing, that is the biggest thing that I would like largened from my current highend setup. Any knowing, willing, experiences users would be appreciated.
For stellar imaging you need to go with mono amps (or a stereo amp with 2 totally separate power supplies). Any amp which shares the power supply between both channels is likely to have some crosstalk issues which can have a noticeable effect on imaging.
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As I said in my many posts to all of you.............et al..............majorly goodnight..............you really.........except for the few in my other posts........you have NOTHING and subsequent to the conversation.............say hay to AMY......................bye................I will be looking in'...............Dale.
Dale, you have asked a question which has no answer (unless you pose it to yourself). An amp, especially a tube amp, can't be considered in isolation from the speakers with which it is used. The best sounding amp with K-horns may be totally unacceptable with B &W 801s. And even if a specific speaker is named, you will find as many opinions about the "best" sounding amp as there are folks who use that speaker. Why not find a custom amp designer/builder who will voice the amp in your system to achieve what you are looking for? Since cost is no object, your goal should be easily achievable. Perhaps something like this would give interesting results: http://www.nutshellhifi.com/VSAC2003-2.html
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You will find as many opinions about what the best components are as there are amp designers/builders! When budget isn't a concern, I always use the Hammond 16--SEA series of single ended output transformers. To my ears, and those of the the folks I build amps for, they are excellent and provide great value for the money. 45s are nice tubes and tend to sound lovely in the right system. But, there are other tubes which can do a just as good, or dare I say better, job. So, you really need to have a long conversation with your amp guy and ask for recommendations based on his experience. I've used many triode connected pentode designs for owners of Cornwalls. Depending on the size of your listening room, how far you sit from the speakers, and how loudly you listen those can often be a very cost effective way of achieving the sound you want without incurring a considerable expense. Is the local fellow willing to "voice" the amp for you in your listening room? That refers to adjusting the operating parameters of the amp to modify the resulting sound to some degree. It seems that you're on your way to a great listening experience. Just take your time and ask lots of questions before committing to a definite plan of action.
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Thanks Chris! I'm not accustomed to having to paste the text down here first, and then create the link; but, your method seems to work fine. Appreciate the help and have a great day! Maynard
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Thanks for posting the link. I run Firefox, and for some reason, the link tab won't work (it's not even highlighted). Also, copy/cut/paste won't work either (with those I get a box saying that they aren't supported by Firefox). Any suggestions would be appreciated!
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With LaScalas in a room of that size, and medium listening levels, you don't need much power at all. In fact, 2 or 3 watts/channel would probably be more than enough. While your budget puts you in the zone of some extremely fine tube equipment, it really isn't necessary to spend more than a fraction of that to achieve amazing sound. You need to decide whether you want an integrated amp or separates and check out the various offerings. Where are you located? The best thing is to locate some folks who can bring over a variety of tube amps for you to audition in your own system. Check out the offerings from companies like Decware (www.decware.com). They allow you a 30 day return privelege with a small restocking fee iirc. Prima Luna also has some great amps at far less than your budget. Use the money you save to buy yourself some other "toys!"
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What is your budget? How loudly do you listen, and to what type of music? How large is your listening room? And why do you think you need that much power? Sorry for all of the questions, but clarifying these points will make it easier to recommend suitable equipment.
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Craters and Freighters has franchises all over the country. They pick up the items at your location, take them back to the warehouse for packing, and ship for you. I've used them to ship everything from large heavy speakers and 1930s console radios to vintage communications receivers. They have always packed to survive an airplane drop and everything has arrived in perfect condition. Rates have always been reasonable.
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Very nice overview of different amplifier types and how they work:
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Similarly, in the past 15 years I have had no output tube failures in any of the single ended amps that I've designed and built for local audiophiles and family members who average 2 or more hours of use/day. I'm curious as to how modern tubes stack up against that kind of track record. So, if anyone has experience with that, please post!
I like the SE sound and it is certainly a simpler design...the only gotcha is the power envelop....hard to get high WPC's using a SE approach unless you do what Cary does
on their V12's and parallel's the SE's and drives them with el-84's.
about your track record question....I have in my possession 3 Manley MB-350's which came out of a recording studio. They were in use every business day for the last 19 years. Each amp has 8 KT-90's. 350WPC capable but probally never really driven above 50WPC. Well one of the amps failed after 19 years and 1 power tube flamed out and took out two resistors and two capacitors.Tube life has many factors....how much you beat them towards their max WPC.....heat....high bias......excessive plate voltage....lack of soft start....etc
You are absolutely right about the power limitations of SE designs and the factors which control tube life. I have always preferred that route for up to 10-12 watts out (easily obtainable with 2 tubes in parallel) after which I've had to go to p-p due to lack of availability of affordable output transformers which could handle the current. And then there's the issue of the size and weight of the single ended output transformers too. Some argue that the distortion of SE pentodes is way too high; but, that is easily managed/reduced with some negative feedback at the ouput stage. The resulting smoothness, to my ears, is unbeatable. Regarding the tube life, one of my favorite amps is a triode strapped Philips 6BG6GA which has a 30 watt plate dissipation (basically a 6L6GC which was packaged for horizontal output service in a TV). With 250V on the plate, and idling at only 40ma, this tube doesn't even know that it's doing anything. I wouldn't be surprised to see a life span of 25000 hours or more on this one.
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Makes a nice case for single ended, cathode biased amps! Put in the tube, measure the circuit parameters to see if they're within spec, and forget about it for the next 10,000+ hours!!!
I can see driver tubes lasting 10,000+ hours...but common audio output tubes?
It all depends on how the output stage is set up. With carefully controlled filament voltage (i.e. does not exceed its rating under any line voltage condition), selection of its operating point, and proper ventilation, it's easy to achieve (I'm speaking about US made tubes as I have no familiarity with those of current manufacture). I've worked on numerous communications receivers from the 40s and 50s which used a 6AQ5, 6V6, or 6K6 in the audio output stage, which were operated 24/7, and had no failure of those tubes after 1-2 years! Similarly, in the past 15 years I have had no output tube failures in any of the single ended amps that I've designed and built for local audiophiles and family members who average 2 or more hours of use/day. I'm curious as to how modern tubes stack up against that kind of track record. So, if anyone has experience with that, please post!
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Makes a nice case for single ended, cathode biased amps! Put in the tube, measure the circuit parameters to see if they're within spec, and forget about it for the next 10,000+ hours!!!
A question about high power amplifiers
in 2-Channel Home Audio
Posted
At risk of inflaming this issue, there are 2 factors which need to be considered in choosing how much power is needed. The first is whether the amp can drive the minimum impedance of the speakers, and the second is whether it can play loudly and cleanly enough to make you happy. In the case of tube amps in particular, distortion rises with power output. So, if your usual listening level only requires flea power (as you stated around 0.25 watts, which isn't unusual with CWs), it's likely that your tube amp is producing very low distortion at that level. And as long as the amp's distortion stays acceptably low when called upon to deliver what's needed to handle peaks, you're in good shape. As to high power amps sounding better at low volume levels than low power amps, that isn't necessarily true. If the distortion of both is the same over the needed range of power output, and the high power amp sounds better, it's more likely due to differences in circuit design than anything else. It's also unfair to compare tube amps to solid state amps because the operating parameters (such as damping factor) are so different. OK guys, tear me apart- I'm heading back to the bench!!!