MikeS

I only have the ability to use 3 8" drivers, 2 10" or 1 12" drivers. To push 150+dB's out of a trunk would require a super efficient box, and 2 really efficient woofers. I got to listen to Mike's 8 RE's in his Bronco. It was roughly a enclosure of around 5-6 foot internal volume...(he knows the exact volume and alignment) It had multiple ports, and you could plug some of them to tune lower, or run them all open open for SPL. I was scratching my head when he told me it was a 4 ohm load with a 150 watt Alpine amp. I think he had it tuned lower for music when I listened to it. Efficiency can be your friend.......especially in the home audio world. To say speakers/drivers in general are inefficient, well maybe the generalization can fly in the car audio world. But high efficiency loudspeakers have been around for a good 80 years now. When you only have a couple few watts to work with, you need a real efficient loudspeaker. A 50 watt commercial home tube amp in the mid fifties was about as much power as one could find without having to be a insane DIY dork and resort to building some sort of audio amp with the higher power transmitting tubes of the time. I have a pair of 104db sensitivity loudspeakers. They can boogie with one watt. The FI subwoofer is 95db efficiency? Mike

I fixed your post. and for the record, i'm no grammer ninja, lol. but i try not to ramble and i do try to form, and type, complete thoughts. makes it a bit easier to get my point across. wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee That's good, because you don't use capitals in any of your postings.

Is this the crossover diagram you are refering to? http://www.wadsnet.com/~dtenney/dayton_8MTM.htm They look like seperate circuits from the way the xover program models them. And technically, they are. Say the woofer circuit's + and - inputs are the binding posts, where the amplifier connects. To connect in the tweeter circuit, you just jumper the + and - from the binding posts to the tweeter circuit. If you look at the diagram, and just draw lines from the woofer's pos and neg input to the tweeter's input, that would connect both together. I hope that helps............

That's easy....just drive the car 730 miles per hour...... I remember when in the '70's when I was a kid riding my bike around, and would get blasted by a sonic boom when they still had fighter aircraft at the local AFB. They would hit mach 1 before they left the area. I'd be riding my bike along and WHOMP!! A big pressure wave with a loud thump like a cannon with a muted kinda sound. They had a SR71 blackbird here about 10 years ago, it hit subsonic when it left the area. Thumped the apartment I was in pretty good at the time. Trimmed grass for groundskeeping at the local AFB once. Don't ever trim grass without hearing protection at the head of the flightline when a pair of those damn dual engine F18's or whatever take off in a pair......even at 150-200 yards. Caught me off guard.....I just seen some jets taxiing on the flightline......kept trimming, nose to the ground......next thing I know my ears are getting trashed.....look over and see two F18's and four jet engines pointed at me, taking off. Low frequencies beating off my chest with high frequencies that make you wanna run away in fear. That was about sick loud. Wore hearing protection from then on.....

The audiobahn 15" may have a higher fs up around in that 50-60Hz area. I would guess a driver with a free air resonant frequency of 50Hz is going to be down by 6db at 30Hz......depends on the box and alignment I suppose. With my experiences running swept sine waves with respect to port tuning woofers for home audio, is once you get below the fb the port is out phase with the cone like mentioned,(good post,BTW) and the cone starts a floppin'. SPL is gone, because you are below fb, and well below the driver's fs. Now with a cone going beyond it's excursion limits, I can't seem to relate SQ with that.

http://web.archive.org/web/20041027051204/...rces/fiberfill/ Cool, thanks. It'll help. Mike

Excellent topic. From what I understand, I think Polyfil works in a resistive manner, which goes along with what was explained. I use Dacron/Polyfil quite often in bass reflex cabinets. From my experiences, if you stuff too much in a cabinet/enclosure, it dampens way too much. You'll get to the point where the bass pretty much dissapears. IIRC, it seemed to limit cone movement as well. I dunno.....I ain't too sure.... My experiences have been by trail and error. Add some fill, listen, add some more, take some out. It works well with a speaker/cabinet that is boomy, or peaky at certain frequencies. It dampens the boom and tightens up the bass a bit from what I have noticed. It is at the sake of amplitude and sensitivity. And peaks can be adjusted by tuning the vented alignment which ever way necessary. I have tried poly in a 6 foot enclosure, and it is not as effective, like mentioned. One way to get rid of boomy sound in a enclosure using polyfil is using a AA battery. Hook the woofer up to the battery, and listen to the DC when connected. If it's a big thump, add polyfil. Add fill until the thump sounds more like a mild thud. I never tried this, I just went with the trail and error approach. I wonder if that is some general rule of thumb, calling for a pound and a half of polyfil for 2.5-3.0 ft enclosures, and a pound for larger sized enclosures. What I'd like to know is how one could determine the added volume for the amount polyfil that it "fakes" in the enclosure. So one could have a way (formula) to come up with the numbers for the added volume to add into a box plot program....like WinISD or something. Mike

Some of the commercial offerings of coaxial speakers can make for a really good stereo experience. Some..... I have a pair of B&C 12CXB's in 3.75 foot enclosures. I've got them tuned to around 40-45Hz...I think.....I have a big wad of polyfil in the cabinets, and I am not accounting for the "faked in" volume the dacron gives. I need to hook up a VTVM and a signal generator to watch impedance and determine vent tuning. They ain't optimum, but they have good punch and depth so far. I had them tuned way too low,(32-35Hz) and didn't realize how lean the bass was until I tuned them higher. Dialed in, it's like headphones. I have a pair of Altec 15" 415A Bi-flex drivers. They aren't the duplex tweeter type. They have a sub midrange cone with a outer woofer cone. They need a helper tweeter pretty much, and a rather large bass reflex cabinet, but they can crank out some bass. I was using a Selenium slot tweeter capped off with a 1 mic cap. What I noticed is you can really power into the things without much if any cone breakup, which is a issue with some fullrange drivers. The Altec's have some excellent midrange, voices are nice. If they only had a tweeter in the center.

I picked up a vintage Pioneer SX-780 solid state receiver for a friend. After I cleaned it up real good, and set DC offset, I used it with my Klipsch LaScala's for about two weeks. It's a 100 wpc receiver, and has power meters for each side. One day I tried to push the meters past 1 watt......I couldn't do it, it was way too loud. With normal listening levels, the meters ran at 20-40 milliwatts. LaScala's are 104db efficiency at 1 watt/1 meter. Sumthin' like that..... A 100 wpc amp is like having headroom from hell. It's nice, but OTOH, at the lower normal listening levels those poor transistors seemed like they were barely conducting and didn't sound as good as having the receiver tipped up a bit on the volume. Tubes have better sound (IMO) at those lower milliwatt listening levels, and meshes up better with higher efficiency speakers. A cheap SS reciever or any budget amp will sound cold, hard and grainy through Klipsch Heritage crap or other brands of high efficiency speakers. I don't understand why people wouldn't deal with higher efficiency speakers. It doesn't have to be expensive.

I posted a pic, but didn't list the gear. 1989 LaScala's, with Crites tweeters and K33E replacement woofers. K55V midhorn drivers, with K401 horns. Modified crossover networks, using a combination of Jantzen and Bennic caps. I need to finish them.... Homebrew 2A3 SET stereo amp. Modified Magnavox single-ended 6BQ5 console amp. Harmon Kardon 330B receiver. Two SVS 16/46 CS series passive subwoofers, with a Audio Control PCA with two-way active crossover, and powered by a ol' wore out NAD power envelope amplifier. A older Pioneer CDP. It actually was a higher end unit back in the day. And a Lambda DC tube power supply.....every stereo needs one of those..... Well, that was the configuration that week.....I've been using a 50 year old Japanese transcription turntable the last few weeks. this weekend I'm listening to "Corntecs". Klipsch Cornwalls flipped over with the midhorn and tweeter disabled. And Altec 415A Biflex woofers mounted in them. The 415A doesn't sound too bad at all. Deep strong bass and midbass, with excellent midrange. A little rolled-off on top, but not that bad. A helper tweeter capped off high adds some extra "air". I dunno...I still favor my B&C 12CXB's I think.....I need to compare.....

I scrounged up a Sylvania 6DJ8, and also have a couple of Philips branded Mullard produced E88CC's. I know I have more 6DJ8's around here as well...... This looks rather simple to try for a breadboard circuit.......I have a HV DC tube power supply so all I have to do is cobble up the phono circuit. If I can dig up the right value parts around here. I'll see what kind of sonic mess I can come up with. http://vinylsa.co.za/pdf/A%20Simple%20Phon...C88%20Tubes.pdf

I got cute and scounged up a Shure 800E and weaseled it on the tonearm. Took all the headshell weights plus a penny on top of the tonearm to get the VTA right. Plus a lot of cocking around with cartridge adjustment, and overhang. I doubt if the VTA and SRA is correct, it looks kinda close..... The old Stanton/Pickering 380 cart sounded rolled off on top, but had real nice midrange. The Shure has less surface noise, and more top end. Bass between both is about the same. This TT look's like a dinosuar that eats records, but it's starting to sound rather nice. Through the LaScalas wih a POS vintage integrated JVC SS amplifier, the combination doesn't sound bad at all.

Got it all put back together. I still need to get a stylus and some silicone grease for the unipivot. It's a tanker with a boat anchor on a pivot, but you get the right record and dialed-in, and it sounds rather nice. I'm just wondering if I should try a more modern tonearm tonearm and cartridge with this table....

Yes, it is a idler drive. I never messed with one before either, I'm pretty ingnorant to turntables. I have a couple Dual TT's, one is a belt drive that needs a belt, the other uses a idler wheel or something. This Musicmaster sounds way better than the cheap Dual TT's. I got it all tore apart now......the thing is real simple so I should be able to put it back together no problem. I need to figure out how to get the motor tight to the base, they didn't have it mounted right. I need to get creative and figure out how to mount it correctly, and still have it itself isolated from the base. When directly coupled to the base, you hear motor noise. I cleaned the plinth up a bit, or really the big wood box it sits on. I tore the arm apart and cleaned it up. I need some sort of Silicone oil or grease for the unipivot. I got dumb and set the TT on it's side, and the oil leaked out. The oil helps damp the tonearm, and helps for slow cueing. Then rewire the tonearm mess, and figure out how to get things grounded proper. Then I can ponder out some phono pre-amp circuits.

That blue glow you see is hovering right outside of the cathode, and between the cathode and plate, correct? That's the only blue glow I've noticed inside EL-84/6BQ5 in my experiences. Some larger tubes like 6V6/6L6 and my sovtek 2A3's for example, get a blue glow on the inside of the glass envelope. I can't remember off hand what the cause is, stray electrons striking the glass? You start seeing pinkish/purple clouds or spots, that's usually a sign of cathode poisoning. With cathode arc/death nearing. But you'll hear static from the tube with this condition. Had a NOS 80 dollar 2A3W/5930 do this after a month.....That'll chap a guy's ass, especially with a 30 day guarantee. You may want to hit a place like Guitar Center or a pro sound joint that carries Caig products that JimJ mentions. I'm cheap, and I've had good luck with the RS contact/control cleaner and lubricant. It's worked with many a carbon pot. I used this stuff with that Pioneer SX780 I found for my friend. Worked well with the VC pot, which was really scratchy. "Hows the Altec coming?" I've cleaned measured and tested the PS transformer, you know.....the one with the hole drilled into it. I repaired the burnt insulation on the heater windings. Checked for DCR, and then ran the thing unloaded for a 7 hours, to check for overheating. It passed......it ran rather cool unloaded. I found a posted Sams Photofacts schematic of the Altec 345A posted online. I also have the original operator manual's schematic, but the Sam's schem shows DCR for the PS xformer secondary leads. My measured DCR #'s matched right up. I'll see how the PS xformer holds up with a load when it's in the amp, it should be ok. I emailed and had my retired EE audio buddie explain how to measure a output transformer out of circuit using a signal generator and a scope, using a simulated plate load for the primary and a dummy load for the secondary. Using square waves, I could monitor varied frequency response between each output transformer and check for similiar characteristics, or un-similiar. Basically, I did it to check for possible shorted windings, which would effect the square wave response. They passed, and seem pretty balanced between the two.......not perfect, but close enough. So now that I know the iron is ok, I can continue. I need three 40/40 uF 500 volt capacitor cans. The ol' 49 old ones ain't worth cocking with. Bummer that, those cans are gonna run a good 100 bucks for what I want. I scrounged up six 0.1 uf K40Y 1000 volt Russian coupling capacitors. The ones like in my little Magnavox amp. They will fit with just a wee bit of room. I lucked out. I'll need some power resistors, and some new 50 uF 50 volt capacitors for the negative supply for bias. Also some 50 uF 3 volt capacitors for the 6AU6 bypass cap....maybe I can find a Nichicon axial cap at radio shack in 16 volt with some luck. A bunch of under chassis clean up, and wire cleaning mostly......that's about it....I also need a matched quad of EL-34's. The original tubes are all mis-matched brands. They all test somewhat close, but I'd rather just start over with a fresh quad. I'll save the only two Mullard EL-34's for a SE amp or sumthin'. I also need to find some 6C4's. I need around 200 bucks to do all this. But I got bills at the moment, so I've just been "prepping" more or less. I'm currently sanding all the mouse markings off the chassis. It's a major chore I hate it, but the metal comes out pretty much like chrome. Hopefully, this amp sounds clean and powerful enough to make my LaScala's boogie when I got a few beers in me. I'm a no life......yikes

You may as well just run the amp with the cover off, save yourself brain damage. You'll get better ventilation...one thing a tube amp likes is lots of air around it. Have you tried cleaning the pots yet? Sometimes if you work them back and forth you can work them back in...sometimes. Whatever you clean the pots out with, go ahead and and buy a can of compressed air as well. Spray the cleaner into the pots, work them real good back and forth, and then blow them out with the compressed air. Do it a couple times. Then blow them out real good, and let them dry for a few hours, a day, or whatever. They should do better after cleaning, sometimes they don't. That's kind of bummer with tube vintage amplifiers and integrated amplfiiers. They use strange value pots with various designs, (like dual-ganged) that are hard to replace. AES may have 1 meg replacement pots, but they may not look the same way in design. Or be dual-ganged. Then they has the infamous ceramic coated "PEC". Printed electronic circuit I suppose it means. There are ceramic square looking things with several leads going to them. They have internal capacitors and resistors in them, and are tied into the tone pots. Do the tone controls sound ok? Mike

72" telelvision.....nice. You want a big HT audio system, not one that fits in a box. If you have a budget and not too concerned about time, maybe start off with getting a nice pair of mains for front left and right. And not little bookshelf speakers either, some good sized floorstanders.....you want the sound as big as the screen. Start off with 2 channel first, or 2.1 with homebrew subwoofers or whatever. Get a 5-7.1 AV receiver to use to start off.....Now price reflects SQ and build quality, so if you buy a cheap AV receiver that's what you get. $1000-1500 would seem to get into a decent AV receiver I guess. I used to just watch DVD's in 2.1, but I have pretty much resorted to 2 channel stereo listening. Don't have the money nor the room to build a HT rig I would want.....so I'm kinda ignorant to the HT hobby with respect to building up a system. But a $6K TV deserves a audio system that kinda reflects the TV's price, if you want to have a impressive HT system. IMO.

http://www.soundsolutionsaudio.com/forum/i...;module=gallery There....pictures of my crap....

Howdy, I'm used to the common generic message board formats. This one gives me brain damage. How does one post pictures directly from a hard drive? I don't have host site, and the URL links seem to indicate code errors when I add a link to reference a picture. I notice you can do it with a personal avatar. Love these smilies.......especially like this guy.... I dunno..... I dunno....

Yeah, you are right. After looking at the schematic, I notice that. The actual chassis ground symbol is designated like a rake. Plain grounds look like a upside down christmas tree. You would think all those ground shields in the cables ties in somewhere to chassis ground. The 47K input resistor at the mag phono input is pretty much the grid resistor for that grid of section 6EU7 it feeds into. It also sets the input impedance I think as well.... I almost have to have the amp sitting here to trace out, but your gonna do it. When I have scratch built amplifiers, the way I've been kinda taught is to like run a ground bus from the PS first cap's ground. You also run the PS xformer's CT to the first cap's ground. From there you run the ground bus to the input jacks, and chassis ground at the input jack's ground pin. Then you try to configure all the HV grounds, (PS, output stage) as close to the PS section as possible, working your way to the lower voltage tube grounds and then signal grounds as you go to the input jacks. There is star grounding. Which works well, but in this case it takes less wire to ground to a bus than running several ground wires to one spot. One good rule of thumb is to make sure the PS transformer's CT is tied to the first cap ground of the power supply. I'm sure the Heathkit is....It's obviously has HV chassis grounds separate from the signal grounds. Old vintaqe tube amplifiers used several ground points on the chassis sometimes.....it can be a PITA. The best thing is just leave things be, and make sure all ground points are clean and well-grounded. Cool, it worked....the TT ground.... Mike

All my droning boring threads......gone.... I wouldn't have patience to cock around with it either. AK does have some real flakes on there, but some members are good folks. If you to find folks that rub you the wrong way, go to the Klipsch forums. There is some real douchebags on there......but there is some good people there I have known for years. I did AA around 10 years ago.....I dunno....good for archive searches. DIYaudio is great for archive searches as well. The DIYaudio forums have posters from world-wide, so there is some attitude and ego going on there from what I notice. And it can get rather technical, which kinda intimidates someone who doesn't really know what the hell they are doing. Audio message boards, you can learn quite a bit from them. But it seems whenever I have some real questions, I have to resort to emailing my retired EE audio friend for answers. Or just wing it and figure it out. There is also another retired audio engineer locally, that I need to keep in touch with more often. He's a good resource for help as well, and has just the most excellent stereo rigs. Mike Stehr.

If you look at the schematic, the grounds of the jacks go to cables with a shield wire for ground. Follow that shield ground wire, it shows on the schematic that it goes to chassis ground. You also asked in the PM from AK about where to ground the turntable on the amplifier. Pick a spot on the chassis somewhere convenient. Try it first and just touch the ground to the chassis from the TT. It'll probably hum until you do ground it to the amp's chassis. Whether it still hums when grounded to the chassis......that's something you'll have to find out......

How do you post images on this site? Like right off my HD?