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Nice, I had a KA-3500 at one point. I loved that volume knob, it had such a satisfying click.
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Apr 24, 2013 16:12
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BANME.sh posted:There's a few nicks on the original wood plinth which I intend to replace with some kind of fancy hardwood, eventually. Walnut and maple to get a similar look! Example I whipped up in SketchUp 
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Apr 24, 2013 16:41
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My tube guitar amp takes more than a few minutes to warm up. More like 5-10 minutes of playing to get the good tube sound out of it.
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Apr 24, 2013 19:04
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Blistex posted:Walnut and maple to get a similar look! I am actually thinking of going with something a bit more exotic. I really like how this Zebrawood looks: http://www.vinylnirvana.com/vintage-turntables-for-sale/thorens-td-125-mkii-wsme-3009-series-ii-improved-arm-custom-zebrawood-plinth/ 
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Apr 24, 2013 19:18
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Would a full-metal plinth cause a lot of problems? I mean obviously one would have to be careful with insulation but there's these leftover bits of 10 cm steel just strewn about outside the gate at my workplace and I'm sure I could get one of the customer's guys to plasma cut me a suitable piece.
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Apr 24, 2013 19:24
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Philthy posted:My tube guitar amp takes more than a few minutes to warm up. More like 5-10 minutes of playing to get the good tube sound out of it. Yeah, tubes have to hit a certain temperature before they stabilize since their design is based on thermionic emission. A good number of solid state devices take a bit of time to warm up as well. Mosfets have a negative thermal coefficient and the current passing through them will drift around for the first 10-20 minutes.
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Apr 24, 2013 20:38
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Jerry Cotton posted:Would a full-metal plinth cause a lot of problems? I mean obviously one would have to be careful with insulation but there's these leftover bits of 10 cm steel just strewn about outside the gate at my workplace and I'm sure I could get one of the customer's guys to plasma cut me a suitable piece. In theory, metal would resonate more than wood. (It rings when you strike it, right?) That could be bad. Or negligible. I really don't know how it would work in practice as a turntable plinth.
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Apr 24, 2013 22:38
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Finally got home and hooked everything up for testing purposes. Got the new receiver hooked up and its making one speaker louder than the other even after cleaning the posts, switching wires. When I switch the red/white from the record player it makes the alternate speaker louder. Any ideas? Anyways have some crappy pictures from my cell.  Klipsch KG 2.2  Technics Sl-D2  Kenwood KA-3500
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Apr 25, 2013 00:36
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Clean the connectors between the head shell and the tone arm, that might help.
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Apr 25, 2013 00:44
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Confirm its not the turntable first by using a different input device, like an iPod into aux. Then confirm its not the speakers by using a different pair if you got them. If all else fails, it might be the DC offset that needs adjustment. You'll have to track down the service manual for instructions for that specific amp (check hifiengine). It will require tweaking some variable resistors on the amp board. You will also need a voltmeter capable of reading mV. Or it could be a dying capacitor BANME.sh fucked around with this message at 00:58 on Apr 25, 2013 |
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Apr 25, 2013 00:54
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BANME.sh posted:Confirm its not the turntable first by using a different input device, like an iPod into aux. Then confirm its not the speakers by using a different pair if you got them. Tried the record player on a newer receiver I have and it sounded just fine out of both speakers, tried plugging my phone into the aux, got great sound out of both. Thinking its the amp. Which sucks. WHen I took it apart there were no blown caps, but yeah, would need to test it with something.
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Apr 25, 2013 01:09
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Could be the phono pre inside the amp then.
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Apr 25, 2013 01:15
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http://servicerepairmanuals.net/hifi/kenwood-ka-3500-service-manual/ $3
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Apr 25, 2013 01:38
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Yeah I already got the pdf for free. Wasn't very helpful, going to talk to my electrical guy at work tomorrow.
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Apr 25, 2013 01:40
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The lazy in me says get a cheapy phono pre amp and toss it on the aux input. Until you can get around to fixing it proper.
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Apr 25, 2013 02:07
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TooLShack posted:The lazy in me says get a cheapy phono pre amp and toss it on the aux input. Until you can get around to fixing it proper. Behringer PP400 Ultra-Compact Phono Preamp?
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Apr 25, 2013 02:22
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I've never had to use one, so I wouldn't know, I'm sure someone else monitoring the thread could set you straight.
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Apr 25, 2013 02:24
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I finished building my record bin, unfortunately I'll be moving in about a month so it'll stay in the garage unused until my new place.  Here's the speakers I built with the Pioneer SX 3800 I picked up a few months ago. It sounds really good, it's so true that tuners were built better on these old receivers, myself and my girlfriend love how the radio sounds on this stereo. 
Meow Meow Meow fucked around with this message at 23:16 on Apr 27, 2013 |
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Apr 26, 2013 02:17
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Meow Meow Meow posted:I finished building my record bin, unfortunately I'll be moving in about a month so it'll stay in the garage unused until my new place. I like your setup. I think that's an SX-3800 though, not a 780.
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Apr 26, 2013 06:48
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Meow Meow Meow posted:Here's the speakers I built with the Pioneer SX 780 I picked up a few months ago. It sounds really good, it's so true that tuners were built better on these old receivers, myself and my girlfriend love how the radio sounds on this stereo. Wow your girlfriend is all over that receiver.  But, seriously, I have major receiver envy and will henceforth embark on a quest to replace my old 80's Hitachi. Where did you find/how much was it?
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Apr 26, 2013 07:22
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Butt Soup Barnes posted:I like your setup. I think that's an SX-3800 though, not a 780. Looks like it. SX-3800 http://vintageelectronics.betamaxcollectors.com/pioneerstereoreceivermodelsx-3800.html SX-780 http://vintageelectronics.betamaxcollectors.com/pioneerstereoreceivermodelsx-780.html
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Apr 26, 2013 13:54
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I think that's him on the receiver. His gf took the photo.
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Apr 26, 2013 13:56
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alg posted:I think that's him on the receiver. His gf took the photo.
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Apr 26, 2013 17:32
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I complained a little while ago about the my Pro-ject RPM1 running slowly, and had an idea the other day on how to "fix" it. The Pro-ject's AC synchronous motor, like most others, determines it's rotational speed from the power supply frequency, not the voltage, by using a pair of coils run above and below a permanent magnet attached to the rotor. As mine was running slowly, and I couldn't change the 50Hz line frequency, I devised a way to make my own, and give me very fine control over the motor speed (within reason). Normally the Pro-ject's motor uses a bipolar capacitor to "fake" the phase inversion for the second coil (energizing them alternately is what causes the rotor to spin), so I guessed that I could treat the two coils like a pair of speakers and control them using a pair of sine waves generated from an external source, and boosted to a high enough voltage by an audio amp. Combine audacity on the laptop and a cheap 20W class D amplifier from eBay, and I have a rock solid, stable turntable with zero speed drift.   (blue and white are the top coil, red and yellow are the bottom one) After a bit of tweaking, I found that 50.75Hz was the frequency at which the lines on my strobe disc didn't move. The next step is coming up with a slightly more portable source for the sine wave (I'm thinking a cheap MP3 player of some sort) and an amplifier that starts up at high volume for maximum torque when spinning up the platter and ramps down afterwards to minimize any vibration in the motor. I also finally got around to rebuilding the gainclone into a much nicer rack case salvaged from a very dead subwoofer amplifier:  Bass Ackwards fucked around with this message at 18:20 on Apr 27, 2013 |
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Apr 27, 2013 18:09
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Anyone have any experience with either a Pioneer sx820 or a Sansui 5000A? Also, condition the same, is one far superior than the other?
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Apr 27, 2013 21:36
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Butt Soup Barnes posted:I like your setup. I think that's an SX-3800 though, not a 780. You're right, thank you. It's not at my house so I took a guess at the model no. Jeff Goldblum posted:Wow your girlfriend is all over that receiver. Picked it up on kijiji for $60. Old guy had 6 or 7 old receivers he was trying to get rid of.
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Apr 27, 2013 23:20
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metaxus posted:I complained a little while ago about the my Pro-ject RPM1 running slowly, and had an idea the other day on how to "fix" it.
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Apr 29, 2013 05:08
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I've seen something like that turntable setup before. I'm sure there's some sort of crystal oscillator circuit out there to generate your waveforms.
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Apr 29, 2013 06:42
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metaxus posted:I complained a little while ago about the my Pro-ject RPM1 running slowly, and had an idea the other day on how to "fix" it. Recalling you're a pretty big geek (positive way) have you seen the Altmann DIY turntable? This is like a much fancier/cooler version.
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Apr 29, 2013 20:31
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Paperweight posted:I've seen something like that turntable setup before. I'm sure there's some sort of crystal oscillator circuit out there to generate your waveforms. Isn't that what the "Speed Box" is for? http://www.project-audio.com/main.php?prod=speedbox&cat=accessories I think the DIY is really cool though.
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Apr 29, 2013 20:44
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My wife's 40 Dollar yard sale find. Needs a new capstan belt, it was old and mushy, as soon as I turned it on and the motor was engaged it broke. New one ordered from Pioneer today. I don't think I will ever be able to top this score ever.
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Apr 29, 2013 21:03
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Ron Burgundy posted:
 I'll chime in with Ron Burgundy's warning. When I was assembling my first set I bought a used Technics SLJ2 linear tracker for novelty value. It had a very small footprint and a neat optic system that allowed for track selection. Needless to say, it cut up most of what were the beginnings of my record collection. They're great as conversation pieces, but that's it.
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Apr 29, 2013 21:06
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I hate to disagree with someone who was agreeing with me, but I was speaking specifically of vertical linear trackers. I have owned the extremely similar SL-J3 for many years and it is a fine machine. You absolutely must take the cover off and clean off and reapply white lithium grease to the gantry movement if these are left longer than a couple of years.
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Apr 29, 2013 21:15
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I ended up picking up a Pioneer SX-820, Sansui SP-2000, Audio Techica at-lp60 turntable, and an IKEA Expedit. I really love the sound these Sansui's put out. Also, I went to Costco and stumbled across a pre-built LED kit for $30 and was intrigued. I attached it across the back of the case top and sides to give some ambient light. It goes through the full spectrum, but I was partial to blue.  Anyways, thank you thread!
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Apr 30, 2013 04:46
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savesthedayrocks posted:I ended up picking up a Pioneer SX-820, Sansui SP-2000, Audio Techica at-lp60 turntable, and an IKEA Expedit. I really love the sound these Sansui's put out. That looks like a SX-3700. Anyway, recap the crossovers and clean off the tweeter switch with a brass brush, contact cleaner won't touch that hard black oxidation, and they should open up a bit.
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Apr 30, 2013 23:49
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Retarded Pimp posted:That looks like a SX-3700. Yeah, from the research I've done its the exact same, but its the Canadian version with a black face/dial. Internals are allegedly the same. Do you have a write up or a lead to point me in the right direction on what you are referring to? I'm still pretty new to the vintage stuff so it went right over my head.
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May 1, 2013 05:31
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That was a pretty cool way of making a turntable work.Paperweight posted:I've seen something like that turntable setup before. I'm sure there's some sort of crystal oscillator circuit out there to generate your waveforms. Two tape loops, one for the spin-up, switch over to the second loop with your pre-recorded 50 Hz signal. It would be possible to make a system to generate a sine wave for example with a voltage-to-frequency converter, but to make it work properly it should have feedback from the turntable, so a tachometer on the turntable fed into a frequency-to-voltage converter. Stability would depend on the stability of the voltage-frequency converters, but what I just described is basically a direct drive turntable.
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May 1, 2013 11:41
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longview posted:That was a pretty cool way of making a turntable work. IIRC some of Sony's high-end tables did indeed use a magnetic strip on the inside of the platter to track speed stability.
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May 1, 2013 14:34
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BANME.sh posted:drat, that's awesome that you figured all that out, but what an insanely convoluted system to get a turntable spinning properly that should be working fine out of the box. It was fine out of the box when I bought it, about 6 years ago. I don't know why, but the motor doesn't run as fast as it used to... The coils are OK, the bearings aren't seized, mechanically, it's fine. The only explanation I can come up with is that the permanent magnet in the motor has lost some of it's flux over time somehow, and that weakness is translating to it running slow. Not an Anthem posted:Recalling you're a pretty big geek (positive way) have you seen the Altmann DIY turntable? This is like a much fancier/cooler version. I'll be modifying this further soon enough. Going to make a laminated ply plinth for it (like the Altmann table), reuse the bearing and tonearm, and build an air bearing linear tracking arm for one side based on an evolution of the Ladegaard design. My plan involves doing away with the knife-edge vertical bearing and making the arm carrier itself the bearing in both horizontal and vertical planes. It'll take some fine tuning to get it to work right, but it should perform pretty well if I can pull it off. Thanks for the "big geek" comment too... I'm quietly proud of it.  alg posted:Isn't that what the "Speed Box" is for? http://www.project-audio.com/main.php?prod=speedbox&cat=accessories I do have a Speed Box II, but the problem is it outputs exactly 50Hz, which eliminates speed drift from the AC line frequency (good) but is about .75Hz too low for the motor to run at the right speed (bad). Paperweight posted:I've seen something like that turntable setup before. I'm sure there's some sort of crystal oscillator circuit out there to generate your waveforms. longview posted:That was a pretty cool way of making a turntable work. I'm considering ditching the AC motor altogether so it's likely this will end up being a moot point. I think it's going to be far easier for me to go down the path of a smallish DC motor backed by a PWM controller of some sort with a strobe disc under the platter and an optical sensor controlling a feedback loop for the motor speed. I'll need to get a new pulley as the Pro-ject one is designed for a motor spinning at 300RPM, and the ideal speed for a DC motor will probably be double or triple that. The AC motor also cogs like a bastard and would require some fairly serious isolation, where I can hang a DC motor on an elastic mount or rubber grommets and it'll be virtually silent. I'm pretty average when it comes to micro controller programming, so I think it might end up being my first Arduino project, with the added bonus of being extendable for adding things such as a speed display and easy 33/45 selection, etc... And if I build my air bearing arm, an Arduino could easily control a servo and a stepper motor for cueing & moving the arm hands free. Now I think about it, I could probably also incorporate optical sensors for record sizing and detecting the lead out grooves, which would make it fully automatic, but that's probably getting a bit ahead of myself.  Fernando Bumface posted:
Ron Burgundy posted:I hate to disagree with someone who was agreeing with me, but I was speaking specifically of vertical linear trackers. I have owned the extremely similar SL-J3 for many years and it is a fine machine. You absolutely must take the cover off and clean off and reapply white lithium grease to the gantry movement if these are left longer than a couple of years. Fernando, I'm with Ron Burgundy and convinced that your SL-J2 had something wrong with it if it destroyed your records. I don't have any experience with vertical linear trackers, but I *do* have an SL-10 (the granddaddy of Technics linear trackers) that I rebuilt from what was basically a wreck, and have repaired countless other arm-in-lid Technics turntables. Providing these units are well maintained and have the arm sensor (and cueing damper) correctly calibrated, they're one of the gentlest consumer level turntables I've ever come across... The nominal tracking weight for these P-Mount tables is between 1.25 and 1.5g, and the arm servo response is virtually instantaneous. They (the SL-10 at least) can also sound utterly, jawdroppingly amazing with the right cartridge and spotless vinyl. minivanmegafun posted:IIRC some of Sony's high-end tables did indeed use a magnetic strip on the inside of the platter to track speed stability. This is also the reason that a lot of those really rare Sony turntables are now unrepairable. The magnetic strip loses it's polarization or field strength over time, the processor can't detect the platter speed, and they refuse to do anything other than spin half a revolution and stubbornly stop. Don't even get me started on the Biotracer arms. Bass Ackwards fucked around with this message at 16:45 on May 1, 2013 |
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May 1, 2013 16:30
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Ha, I got a Sony PS-X800 on the cheap, was gonna try and fix it. The more I dug into it, I said screw it. It's up on ebay now for parts. The other Sony I have is full of sensors too, and it's not even a linear tracker. So it's just gonna break randomly one day I'm sure.
TooLShack fucked around with this message at 18:59 on May 1, 2013 |
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May 1, 2013 18:51
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