erik2A3

Your CD player has an output Z (impedance) of 470k ohms??

Just out of curiosity, what is the output/input impedance relationship between these components right now, and is it possible, if you are interested in the potential effects of valves in your system, that a tube-based linestage preamp might be something worth investigating?

Many thanks for the link to cartridge setup and alignment. I got my records out again for the first time in many, many years, and was really kind of astonished by 1: how orgainic and seemingly tangible the sound was, where notes had real depth in addition to just sounding clear. I received a gift of an older Denon table from a friend that is really great, and has put me in search of something along the lines of Clearaudio Concept (MC).

Dee: I think as you about it. Do you have an SB Touch, by any chance? I found it to be really more transparent than the earlier model, and I unexpectedly also found that ripped CDs played via wireless (which is an old term in and of itself!) sound quite a bit better than playing the CD on our CD player -- a Cambridge, which suddenly decided it wanted to quit its job.

We have been using a squeezebox classic and touch. I've enjoyed them very much! Convenient, reasonably easy to use, less involvement...........and then someone very recently sent me an older but still very good Denon turntable in exchange for some amplifier repair work I did for him. I had completely forgotten how organic and 3-dimensional well-recorded vinyl sounds. I still enjoy the Squeezeboxes and internet radio as sources for daily headphone listening, but I am relearning some things I had unfortunately forgotten about what at one time had been for me the only and most real-sounding way of storing and replaying recorded music.

If the required value of C309 is 10uf, 100nf is incorrect. 100nf = .1uf. Hookup wire is simply wire (of correct size and voltage rating) used to connect electronic components together. Jeremy: I respect your tenacity and desire to fix this yourself, but it honestly might be worth considering a professional repair.

Good job with the resistors. As mentioned, that cap had the potential for a little difficulty because it has to be removed, the connection area cleaned and solder flux removed, and the new part installed. That the pad has lifted does not necessarily mean you wouldn't be able to make a bridge with a fine piece of hookup wire connected to the same place the damaged part of the trace leads.

Thanks for taking the time to share your descriptions. Erik

Jeremy: You had correctly identified other resistors, as well as the fuse, in other parts of your post, so it's obvious this was just a simple mix-up....easy to do. C309 is s surface mount capacitor, and SMT components can be kind of tricky to work with. With stuff like this, sometimes it's honestly easier, particularly if you don't have the correct equipment and experience to make the repair, to replace the entire board, although I know that must seem kind of drastic. So, if replacing just the resistors helps, that's good, but that little C309 guy has seen better days, and is not looking very good. It seems to me this is more than just a resistor going 'bad' which is kind of rare but of course not impossible. Whatever happened seems to have affected more than a single, isolated part of the circuit. If you have doubts about anything, please get some help from someone who knows this equipment. Perhaps the manufacturer can help with this. Sometimes professional troubleshooting and repair can cost enough to make one consider a brand new replacement, which is not a slight to anyone. We all need to earn a living! erik

Jeremy: FWIW: the brown resistor is in bad shape, and shows signs of gross overheating. If you look at the body of the resistor, it is badly crazed ( a term that referes to the fractured appearance of the outer 'shell' or body of the resistor. Also, damage in electronics is not always visible from the outside, so a quick look around to see if anything else is wrong can be, sorry to say, totally misleading. The resistors may not be the only problems, as mentioned before. There is an electrolytic capacitor that to me is suspect as well. It is in close proximity to one of those resistors, and there are signs of either leakage, scorching, or both near the bottom. For the boards to get discolored to the degree they are indicates that things got very, very hot in there.

and an FYI: To read the values on the resistors on the board in this case requires knowing the color coding of the bands. There is information available through the usual searches for that. Measuring with a multi-meter may or may not be suitable because of potential -- probable internal damage. and BTW, there is another part that should be considered, too. There is a single nearby diode, which appears to possibly be a zener, that also shows signs of extreme heating. That should be checked, as well. The whole unit should be inspected for safe operation, particularly if left, as seems to be the case above, unattended. How can one be too careful with this sort of thing? edit: if you check the image that shows the fuse, there is a light-colored, disk-shaped component just behind it that looks similar to a ceramic capacitor. My thought that it is an MOV (as mentioned above) has been confirmed by its part number. My opinion is that simply replacing burned and damaged parts without trying to determine the cause compromises safety of self and possibly others. I would get it checked out, Jeremy. Erik

You'll notice, Bruce, I didn't refer to any specific part -- fuse or resistor, although I did mention the large capacitor. The point, again, is that problems like this (regardless of part involved -- L,C, or R) can be symptomatic of problems elsewhere. Good luck Jeremy, and if replacing a couple of resistors is all this takes, wonderful. Are you able to solder, and are there any static precautions that need to observed with this component? There are some things that could be important to consider prior to doing ANYTHING, and it surprises me that others are not mentioning that. There is not even the slightest doubt that those resistors in question should be replaced, and possibly the capacitor, as well (the circuit board will have to be removed to do that correctly, BTW.) Looking at the pictures again, it seems there may be an MOV present in the PSU, which would of course offer protection against heavy line transients.

Jeremy Nice closeup work on those pictures. A brief thought on your situation with this component: Damage such as this often suggests the presence of some other problem. It's not unlike discovering water- damaged and stained acoustic tiling in a ceiling, and then trying to fix the problem by just replacing the tile with a new one -- when the real problem is a leak in the roof; the newly installed tile will be fine until the next downpour. Speaking of which, was there any chance you had a lightening and thunder storm in your area on the day you discovered this? It's mildly possible the cause were the parts themselves. I don't know what power supply components are associated with this, but it would be far better to send the unit out for a professional evaluation and repair. There may be a very real shock hazard present. It appears that there is a filter capacitor in one of the pictures, and those can hold dangerous charges for days. Moreover, that big cap may be included in the damage report too. BTW: I recently repaired an amplifier with a very visually similar problem, which resulted from a short circuit elswhere that found it's way back to the power supply, taking out several capacitors amd resistors in the process. Good luck, erik

Not a dumb question in the least. One thing you might try is removing one of the binding post nuts from the speaker in the other channel. Take it to a home improvement store (hardware/fastener section), where most have an assortment of threaded studs just for this purpose. Try the nut on those until you find the one that's correct, note the identification of that specific thread, and you have what you need.

Just for clarification ( I've been making bunches of typo errors myself, lately. )I think Don Keele (rather than spelled with a 'D') is the person to whom the abve response refers. BTW: when designing for sealed or vented, QTS can be a general guide with some room for variation. I have used drivers with TS parameters that suggested or pointed toward one alignment more than another, yet actually sounded better with the one less favored for that specific driver. Moreover, it's possible to experiment with resistive venting as an often very good compromise between one or the other.

I agree that it would be good to listen to stock configurations first in order to establish a base line for comparison against anything else you might like to try, whether it be a product of a large corporation or small, yet possibly very competent manufacturer (which, I believe, the highly regarded founder of this company also once was). Try to audition, if you can, examples of everything you may be interested in and base your decisions on what you, personally come to like most -- regardless of the size of the company that produced it. Whether hand made jewelry, amplifiers, or anything else -- small industry is certainly not necessarily something to avoid, in my opinion and experience. That said, I've been very pleased with the original metal horns in la scalas and k-horns, but can't help be a bit curious about some of the designs of others. It never hurts to try anything as far as a possible modification, and in fact can help reinforce your impressions. And beyond that, be as safe as you can and enjoy time at home with your family. Erik

I agree. I have a small, 4 watt 6BQ5 (12ax7 driver) that actually has what to my ears is a more evenly balanced frequency response than some 2a3 amps 8've heard, but perhaps not quite the euphonic quality of the triodes that can be favorable.

Listening to La Scalas in the near-field late at night with a low power SET amp of whatever flavor can be magical. They can be like extremely good headphones with real frontal imaging rather than great sounding music lodged in the middle of one's skull.

Personal preferences aside for a moment, it would be helpful, I think, to learn some other facts related to this application: room size being an important one. Triodes seem to be very good in terms of midrange in general, with one or another offering balancing that with appropriate bass response. I have an OTL amplifier that is very close to the 45 in terms of power output, but unfortunately can't be used in the room for which I thought it would be suitable. I tend to listen at rather lower to moderate volumes, and 1.5 watts just could not load the room correctly, even with vocals, baroque, and acoustic jazz. This was surprising, because I LOVED the amp when it was in a small area. BTW: a preamp out is not needed to run subwoofers if the subwoofer has speaker level inputs. Mind you, this does not imply that one is obliged to use the speaker level outputs from the subs to the main speakers, which frequently have a dividing network in series with it (for crossover ranges around 80 to 100 cycles or so). Connect both the subwoofers AND main speakers to the amp, and in most cases impedance interactions are not a problem. It's how I've been using our SVS subwoofer with the 300B monoblocks. A 45 SET might be just the ticket! So might something in shades of 2A3 or 300B.

Awesome! Thanks! erik

Bruce: Correct diagnosis. So, let's test: The thing about coupling capacitors is that frequency response seems to be influenced by the color of the capacitor, not to mention the width of the soundstage, which can be measured by a special type of caliper (the best being made from teak). One holds the very large caliper out in front of the system, about 10 feet from the speakers, and measures where the soundstage/image begins and ends. The above statement is utter nonsense, accept the part about the best soundstage calipers being made of teak. Erik

Or.... Sophia Electric "Baby" costs less than a couple pair of 2A3s and 300Bs that I own and is another amp that shines with the bigger Klipsch Heritage boxes. As its name suggests, it is a small, bit very heavy amplifier. I would say a down side is that output tube choice is limited to what is supplied by Sophia Electric. My wife gave me one of these as a holiday gift, thinking it a very "cute" little thing. The sound of that amp and Klipschorns, however, is not one I'd describe the same way. For the cost, soumd quality is very good, and is one tube amplifier that reminded me, somewhat of the well known class A Monarchy solid state amplifier ( which I ultimately found less involving than I would like....subjectively somewhat 2-dimensional sounding). The "Baby" had what seemed a similar tonal balance, but with a more tangible, rich, and 3-dimensional presence. I know many really like the Monarchy, though. Next to a recently rebuilt organ amplifier, the Sophia amp is also one of the very quietest amps I have.

The grid chokes are a snap to put in -- and so also to take out. Sell them to me if you don't like them! I have also have Moondogs, as well as two strikingly good sounding OTLs from Transcendent Sound. 2A3s in parafeed (aka shunt feed) topology mentioned above are probably the closest I've heard to a transformer coupled SET amp sounding something like an OTL. All of these are really fine amplifiers! My impression of the 2A3 is also that there is lots of air around instruments, and that I seem to detect an upward tilt...which shouldn't be surprising since these triodes really shine in the midrange. I suppose the 300B sounds maybe sort of 'rounder' in that sense, but again it depends on the circuit, as well as fine tuning with passive parts to one's liking -- meaning coupling cap types, carbon vs metal film resistors, tube rectification vs SS, and so forth.

...in fact I can't get that Baldwin out of my mind! I was thrilled to have found another, completely untouched from its original construction, so that I can make one, with these new circuit additions and subtractions (one of which did something very special....), for my own. The one to which I refer above couldn't be in better hands, and for me that's nice to know. Erik

What's important to keep in my, IMO, is not just the tube in question, but the circuit in which it's used. I built a pair of direct driver-stage-coupled 300B monoblocks last year that are anything but lush. They in fact are more detailed sounding than all of the 2A3 amps I have, in the sense that high frequency response is more sharply and cleanly expressed,but in a way that does not put a microscope on every minute sound -- which can lead to fatigue and result in out-of-balance frequency response. Moreover, the brand of tube certainly has something to do with the overall sonic presentation. I have used KR Enterprise 2A3s in the past, which I like very much, although some describe them as 'transistors in a bottle.' I disagree entirely. It's subjective in that sense. Other differences have to do with output power, with the 300B probably having subjectively better (as in more perceived) bass response, but the sensitivity and efficiency of speakers being used. If at all possible, as with all aspects of this, try to hear some different examples if you can, and choose for yourself. Depending on the output transformer used, it's also very possible to modify a 2A3 circuit for use with 300Bs, and vice-versa. 2A3s use 2.5 volts on the heaters, whereas 300Bs use 5, but there are options for 2.5 volt filament 300Bs. There are options. SET amps can be addictive sounding, but it would be completely error to not mention the very, very good results people have had (including me) with higher powered push-pull options (including push-pull 300Bs and 2A3s). I recently spent weeks completely overhauling an organ amplifier using push-pull 6L6s that caught me completely off guard by how good it sounded. A few changes and subtractions of existing circuitry and re-grounding resulted in an amplifier that truly seemed to have every bit of air and presence of good a 2A3, 300B, or 45 amp, but with much more horsepower and decidedly improved bass response -- for which SET amps, in some circles, do not enjoy the best reputation. erik