Marvel

Mark and Shawn, I understand about not needing a signal on both legs to get the CMRR, but I'm not sure I get the 30db NR in the unbalanced to balanced just by having the twisted pair (like a low Z mic cable) with the rca end tied to the shield. I'm thinking you could tie the one line to the shield on the XLR end and have it be the same, even if electrically they are. Nice Powerpoint presentation even if it does sell the Jensen products. Bruce

Many of you have been praying and sending good thoughts our way as my wife Barbara has struggled in her fight against melanoma. The first standard treatment wasn't working, so we stopped that. In the six weeks she was on it, she had lesions show up on her spine, in her liver and lungs. Her brain was clear. She was then admitted to a clinical trial, to test a new drug. No placebos, she would be getting something that they hoped would work. Everyone had a surprise this week. On Wednesday, the doctor's staff thought that Barbara was too fatigued to receive her infusion of depsipeptide and they decided she should go ahead and have a CT scan and MRI. The radiologist saw several lesions in the brain. There were too many to do surgery or gamma knife and he recommended to begin whole brain radiation. Barbara was admitted to the hospital on Wednesday night and given a steroid to reduce the swelling in the brain tissue. The steroid showed some improvement on Thursday afternoon and she was released to come home. Whole brain radiation will begin on Monday morning at Memorial Hospital in Chattanooga. Barbara should receive ten radiation treatments over two weeks. The radiation expert at Emory, Dr. Peter Johnstone, said the radiation is not expected to shrink the brain lesions but to cause them to become stable and could provide long term stability. Hair loss is expected but regrowth is possible within three months. Some of the new lesions are quite large, and we know at this point that all we are going to be doing is to make her comfortable for the time she has left. I thought I had been dealing with this pretty well. We have received much support, from family and friends, including you folks here on the Klipsch forum. But I guess I'm not dealing with it very well at all. . Even though we are taking it a day at a time and trying to enjoy what we do have, I also have to make decisions and think about life without the love of my life, the joy of my youth. [;-)] Thirty plus years of good times and hard times. It makes a lot of the petty crap here seem pretty trivial. I just wanted to vent/rant/let go a bit. Got to go. It's a sunny day

Michael, I had a 730 for about a week, gotten for a friend of mine. It seemed to me that the receiver portion was weak on it as well. Everyone says the 430 has great sensitivity, but I didn't see it with the 730 model. Bruce

Mark, If pin 1 (ground) is tied to either pin 2 or 3, is is no longer balanced, because it is the 180 degree phase difference that makes it balanced (along with impedance) and offer noise rejection. If they aren't out of phase, there is no benefit. With one of the signal lines tied to ground it simply becomes an unbalanced. circuit. Bruce btw, that's how Cat5 network cable works. Each pair feeds a + and - input. If it didn't, the fast rise time of the signal (square waves) would shunt to ground due to the capacitance of the cable. Wouldn't get very far through the cable before you had no signal at all. That is the other benefit of balanced lines in audio if going long distances. High impedance audio cables tend to lose the high end over long cable runs.

The m00n is often full of himself. Jeff, One of the priests at my church is French. The sermons always sound like I am listening to Inspector Clouseau. Except the sermons make more sense.[] Bruce

Three ways, the third being an active circuit to balance the output of the preamp.

Is the new forum software what is causing everyone to be so full of themselves lately? It doesn't matter what anyone says and someone is jumping all over them. I think I'll take another break.

Craig, I'm trying to be reasonable here too. Shawn didn't mention 26 ohms. What he did say is that with .5 amps going through the ICL ( 25% of the 2 amps rated current for the device) the resistance will drop from 120 ohms to 8 ohms (7.8 in the chart) in 120 seconds. So, yes, it does have something to do with what you use. Bruce I think your resistance goes up as you get heated. []

edwin, A tungsten filament in a light bulb has an extremely low resistance when cold, so draws a lot of current. Its resistance goes up as it heats up (positive temp coefficient). They heat up fast, and it is often the thermal shock that causes them to blow on first turn on. The main thing is that an ICL has a negative temp coefficient (resistance goes down as it heats up). The one that Shannon parks uses is a CL-90, which has a resistance when cold of 120 ohms. Resistors act as current limiters (for example, most l.e.d.s have a resistor in series to limit current flow through them). Caps act as a dead short until charged (as well as other devices). The voltage drop across the ICL, causes current through it and as it heats up, the resistance actually drops. This should mean that more current flows through it, which would be true if the caps didn't charge up. The resistance in the caps becomes higher as they charge, which then limits the current through the circuit. The ICL has then heated up and its resistance has dropped to a fraction of what it was. If you hooked up a CL-90 and a 120 ohm resistor in series across a 120v line, at turn on each device would have a current flow of .5 amps (120 ohm ICL and 120 ohm resistor= 240 ohm total, I=E/R). As the ICL heats up and its resistance drops, the current will go up in the circuit, due to the fact that the resistor value doesn't change (unlike resistance through caps, tubes, etc.). The ICL should drop down to about 1.2 ohms. That means the current through the two devices is now going to be .99 amps (1.2 ohms ICL + 120 ohm resistor= 121.2 ohms, I=E/R), almost a full amp. If that was feeding a cap, there would be a resistance in it after being charged. It is called ESR (equivalent series resistance), and is the resistance of all the parts in a cap at a certain frequency. Then the current would drop back down. The circuits end up being pretty complex, so that in reality there is a lot more going on, but that is it in another one of my nutshells. Bruce

Some audio gear with xlr connectors aren't really balanced. Some, depending on the vintage of the gear, will have pin 2 or 3 tied to pin 1, which is the ground. Others use cheap opamps to balance the circuit electronically, so that you are really better off going unbalanced. Good transformers cost a lot, because they have to maintain the freq. response and power handling for line levels. It's all about trade offs. If you want to go the electronic route, you can have a look at these boxes from Henry Engineering: http://www.henryengineering.com/matchbox.html This one is a two way, designed for sound cards on PCs, but could still be used. Bruce

Well... we have about ten or twelve turkeys that wander through our yard every couple of days. Nobody owns 'em though.

If you run balanced lines, they can be hundreds of feet long with no degradaton of the signal quality. A balanced line has two signal lines that are 180 degrees out of phase with each other so that noise picked up in the cable (emi, rfi, etc) cancels out. So there is great noise immunity with balanced cables. Also usually low impedance, which is also a plus. Unbalanced cables (rca/phono, 1/4 inch phone) don't have the same luxury. The impedance is also usually higher, and with the capacitance of the cable involved, will cause high freq. rolloff on long cables. They also cannot reject/cancel the noise picked up from emi, rfi, etc. You can balance the output on a preamp with active electronics or with a transformer. A high quality transformer would work better (Jensen or Lundhal), but the cost would be greater. For short cable runs, you probably aren't going to be able to tell the difference. Once inside the amp, it's all unbalanced. It wouldn't have to be that way, but the cost would go up dramatically. High end audio consoles are balanced all the way through. Bruce

Exactly Duke! A good amp is a good amp, whether tubes or ss. Bruce

Here are a couple of links to folks who have done some of this: http://www.dcchomes.com/Heresy.html http://forums.klipsch.com/forums/249053/ShowPost.aspx Gregg has a page with LaScalas and KHorns too, but I can't find the link yet. Bruce

I'm using the SED EL34 in mine, and am quite happy with them. I have a new front end, so that doesn't apply (NOS 6922). I have my original 5AR4, which is still working just fine ( at 35+ years). Bruce

caffeine (kafen') , odorless, slightly bitter alkaloid found in coffee, tea, kola nuts, ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (see cacao). It can also be prepared synthetically from uric acid. While relatively harmless, it is the most commonly used mind-altering drug in the world. When used in moderation, caffeine acts as a mild stimulant to the nervous system, blocking the neurotransmitter adenosine and resulting in a feeling of well-being and alertness. It increases the heart rate, blood pressure, and urination and stimulates secretion of stomach acids; excessive intake can result in restlessness, insomnia, and heart irregularities. The effects of caffeine vary from person to person, as people excrete it at different rates. Physical dependence and unpleasant symptoms upon withdrawal (headache, fatigue, depression) are common in regular caffeine users.

I understand turns ratios quite well thank you. I guess I was missing that the 5AR4 is not directly heated. I hope you understand I am not trying to argue, but to understand where you're coming from in this. Bruce

Having the one horn on top looks a lot better too. Unless you are impressing the ladies with your horns. Bruce

That's great and I do it all the time. However, if you upload a pick that should be able to fit in the frame/table correctly, and it shrinks them smaller automatically. The old way wasn't really that hard to work with, and gave us a lot more options. (end rant) Bruce

This can't be right at all. That all comes off the high voltage winding and on a Mark III transformer, it only supplies about .2 amp (200 ma) on the output windings. One heater reuires more current than that. The heater on a single KT88 is eight (8) times higher than what the high voltage secondary could provide. BTW, explain what the drawings are supposed to tell me.

Dennis, Those quotes are all interesting. Dana's drivers use a polyester diaphragm (I'm sure you knew that), where most would assume the titanium for high power use. The 4591 only goes up to 9Khz (I'm sure you knew that as well). I guess one just has to trust their own ears eventually. We'll see if Dana likes his after a few weeks of listening or if it is just the 'new and different' that he likes. [] Bruce

Okay. I don't understand. First, why is the 5U4 an 'instant on' tube? Why does it conduct immediately compared to the 5AR4? I have other work to this morning, but I may have a second question later. Bruce

I have a '79 Spitfire just waiting to get restored. My son and I are contemplating a Mazda rotary engine for it. I only have about $100 in it so far. Body is in excellent shape. I would agree that the Miata would be a great car to get.

I think it was when I sold a 3/4 size Gibson hollowbody electric. Body was about the size of a Les Paul but about 3 1/2 inches deep. Brown hardshell with pink plush. $100. Or when I sold my tube Bassman head and dual JBL fender bottom. That's why I still have my '40s Gibson lapsteel. It rocks with the single coil! Bruce ... slippin' on stage. I can just imagine Duke...

Dana, What's the difference between the 4590 and the 4590P? Looking good to btw. Bruce