Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Seduction => Topic started by: bainjs on March 29, 2012, 03:55:59 PM
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When I did the resistance check, all the values are correct except for A3,B3 and A8,B8. The manual says the values should be 1M ohm +. I'm getting .0L for all of them. These are the LED connections on page 32. The silver side of the LEDs are oriented correctly.
Any help is appreciated.
Joel
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1M+ means "more than 1000000 ohms" - in other words, a very high resistance. OL stands for "overload", in other words, higher than the meter can indicate. The purpose of this measurement is just to make sure you have not shorted the LEDs accidentally, or damaged them with excess heat, either of which will cause a much lower resistance reading.
Background: the LEDs need more than 1.5v applied before they will conduct any current, and most meters use less than 1.5v to test resistance , so you almost always get a high reading. But it varies from meter to meter, so it's hard to predict - the actual value can be all over the place.
Incidentally, the LEDs conduct in only one direction, so you might get different readings if you reverse the meter leads.
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I suspected that was the case, but wanted to make sure before I went to the next step.
Thanks Mr Joppa!
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I finished the Seduction and played it a few days before I installed the C4S board. I'm really pleased with the outcome. I do have a question: I'm getting a faint buzz when the volume is fully up. Is this typical? I can't hear it at normal listening levels. When I turn the unit off, the buzz goes away so it's not the Foreplay or SEX.
thanks
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Joel,
Try a pair of shorting plugs in the input rather than the TT leads. See if that cures it. It could be the TT/wiring that is the source of noise.
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Is the noise equal in both channels? The right channel is theoretically more likely to be noisy because it is closer to the power supply components. The design does allow for an internal shielding chassis to be installed if needed, but I don't think it has proven necessary very often. This is primarily a strategy to block out RFI and other nasties, it might help whatever the source of your issue is.
More likely, however, is that your noise is the noise of the tubes. You could try another pair, but it also sounds like it is at such a low level that it is basically a non-problem. I also found that the springs in the tube shields exacerbated my microphonic tubes and removing them made a big improvement. YMMV of course, and use a tool NOT your finger to poke out the springs...
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When you turn the unit off, you also kill the signal from the turntable. I'd bet that the turntable and/or phono cart has got the be the source that is the biggest PITA in terms of hunting down noise (hum and buzz) . Well, aside from maybe the computer as a source (dont know about that yet). I had a hum and buzz from my table and/or cart when I set seduction up. This was for the headphone system where it could really be a much bigger annoyance than with speakers. It was only at fairly high volume levels. Drove myself nuts troubleshooting. It was as simple as flipping over the turntables non polarized 2 prong plug. The hum is essentially gone now, the buzz is not completely gone but inaudible unless the volume knob gets pretty close to wide open, far louder than I could possible listen and it would only be heard when the needle was in dead wax. On a related note, I have a slight amount on the main system (loudspeakers, not phones) as well, different stage, different table. Again, not obtrusive at listening levels and volume needs to be up pretty high to hear it. I remember that there was some on my first real system years ago as well. Point is, while Im sure some folks have dead quiet vinyl systems at full clockwise rotation of that "volume knob", I highly doubt that it's uncommon to have a little bit which shouldnt be a problem if it is unobtrusive when listening.
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I too have a very slight hum when wide open, but when I used the shorting plugs instead of the Cartridge the hum is gone. Most noise I have experienced comes from the TT or Cart. Some carts are worse than others as well as some tonearm wiring is not as good as others. At the levels I have to turn it up to for the hum to be noticed it would like destroy my speakers, eardrums and get me evicted in that order. At normal levels even when played through extremely quiet passages of music it is impossible to notice. Also, no matter how much care we take with tube purchase there will always be a chance of tube noise at those levels.
One thing you can also confirm is that the metal shields on the tubes are, in fact grounded, this is easy to confirm with a meter. I had a case once where the painted top plate actually insulated the tube shield, entirely my fault for not properly cleaning before installation. Even then the hum was hardly an issue.
Cheers
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Mike, good point!
Joel has heard my system with both the Seduction and Eros in it. My Seduction has a little hum, no buzz. I don't think he ever heard it . And maybe I turned it all the way up so he could hear it. But at my listening chair, where I listen, there was nothing to be heard.
BTW, Joel, you have boxes winging (joke) their way to you as of yesterday afternoon after my pacemaker battery check.
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I got it backwards ... buzz is gone, tiny bit of hum.
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Grainger,
I received the caps and LPs today. Thank you. Paula's package should be there soon.
I believe I understand the KKs - the .47uf along with the .102 used as a coupler to replace the stock .47uf, correct?
What about the 2uf Obligato - which stock cap does it replace?
Joel
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One more thing about the hum. I disconnected the phono and the hum did not change. I'll try shorting plugs tomorrow. The hum can only be heard when the volume is turned up all the way so I don't think it's anything to worry about.
When I install the new caps, I'll go over all the joints to make sure the solder looks good.
Thanks for everyone's comments! I really enjoy seeing all the different perspectives.
Joel
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Grainger,
I received the caps and LPs today. Thank you. Paula's package should be there soon.
I believe I understand the KKs - the .47uf along with the .102 used as a coupler to replace the stock .47uf, correct?
What about the 2uf Obligato - which stock cap does it replace?
Joel
Yes, the silver bodied KK caps in parallel with the black Obbligato caps. The others are just for fun. You can use them as a power supply bypass cap. They are PETP, another plastic, caps.
Don't worry about hum that is only heard with either your ear to the speakers or with the volume all the way up. Nobody listens that way. If I had turned my system all the way up when you were listening to the Seduction you would have heard a slight hum. As I said elsewhere, I blame audio reviewers for this insanity.
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Now I'm confused. Do I use the .1uf coupling cap with the .47uf or the 2uf obligato?
And if it's to be coupled with 2uf obligato, which stock cap do I replace with them?
Thanks
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The black Obbligato goes at the output. You can use the 0.1uf to either bypass that Obbligato or between stages replacing a 0.1uf brown (mine were brown) cap. They are wired to the grid of the second stage.
Edit: the interstage (0.1uF) caps go from T29-T26 and T39-T36.
The other ones are just to try clipping to other things to see how they sound.
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With the replacement of the interstate and output caps, the hum has become more noticeable. Do you think the extended leads I had to add to the .1uf KKs to replace the stock caps could have increased the hum? I used buss wire for the leads. Could changing from .47uf to 2uf on the outputs increase the hum level?
I guess I can put it back to original and add a set of caps one set at a time to see if I can isolate the hum.
Thanks for your help.
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With the replacement of the interstate and output caps,
Replacement of the interstate? That might be a Federal crime.
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Joel put in a pair of KK Teflons for interstage caps and Obbligato Film/Oil for the output caps.
Yes, the extended leads might increase your hum. What sensitivity speakers do you have. The higher they are the more likely you are to hear the low level hum that is normal with the Seduction.
You heard my Seduction through 94dBW speakers and 3.5WPC. My level of hum was normal, you only hear it in abnormal circumstances. It had 4 of the KK Teflons and 2 Obbligato caps.
Is the Seduction near another piece that it might be picking up hum from?
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Sorry, my iPad has a mind of its own with its spelling correction efforts...
Grainger,
No, it's away from the other equipment. I'll play with it today. I've got some suspicions on the hum source to check. My speakers are 99db .
Thanks
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Sorry, my iPad has a mind of its own with its spelling correction efforts...
That auto-complete thing on my iPhone was making me crazy. I shut it down. It would be OK if it would just suggest a word and let you decide whether to use it, rather than forcing it on you. Whoever thought of that one must have control issues.
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I removed the KKs and put the stock .1uf caps back in. I also checked the tube shields to make sure they were well grounded. Much lower hum, very acceptable.
One other thing, has anyone had their turntable to decide to run backwards? This is a used SOTA I recently purchased. I've been playing it without any problems until now. I couldn't figure out why the leading groove wasn't tracking on the LP to start playing until I noticed the label going counter clockwise. I kinda had a twilight zone moment seeing that. I turned the table off and gave it a little push in the right direction and turned it back on. Seems to be ok now.
Joel
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Do SOTAs use a synchronous motor?
If so, there is a start capacitor that creates a phase shift to one of the motor windings that starts it in the right direction. That cap getting out of spec and starting to fail could cause the reverse start from time to time.
It needs to be the right value of non-polar capacitor but it does not need to be anything more exotic then a mylar type.
I'd contact SOTA and ask what value to use.
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Sorry, my iPad has a mind of its own with its spelling correction efforts...
That auto-complete thing on my iPhone was making me crazy. I shut it down. It would be OK if it would just suggest a word and let you decide whether to use it, rather than forcing it on you. Whoever thought of that one must have control issues.
This is a whole 'nother thread. My brother used to send the most awkward emails from his iPhone (with auto-correct).
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Yes, they use a 24 pole synchro motor. Thanks for the cap info. If it becomes an issue, I'll swap it out.
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Capacitors are a good thing with turntables. My VIP has a ceramic 0.01uF 1kV across the power switch to keep it from making pops when turning on and off and a 2.0uF 200V to get the motor started.
Good thoughts there Wanderer!
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I replaced the .47uf caps with a pair of KKs donated by Grainger. No additional hum resulted and they definitely give it a different sound. A little more body is the way I would describe it.
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I replaced the .47uf caps with a pair of KKs donated by Grainger. No additional hum resulted and they definitely give it a different sound. A little more body is the way I would describe it.
Im trying to remember the Seduction build. The output caps are .47uF, right? Are those what you replaced? I think I used 1.0uF at the outputs, Obbligato golds. I like them.
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No, the .47s are the interstage caps. I used 2uf Obligatos for the output. I believe the KKs aren't broken in yet, but they already sound pretty good. It's time to leave it alone and let it play for awhile!
Joel
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Gotcha. Stock, the kit is supplied with .47uf for the outputs. So, I thought maybe you were using the KK's in place of the .47 orange drops or pannys shipped with the kit. I used the 1.0uf Obbligatos. I also used them in the FP3 (2.2uf I believe). Everything sounds great but I havent rolled any other caps to compare.
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I'm getting a faint buzz when the volume is fully up. Is this typical?
With your level control all the way up, you are amplifying any noise that might be there A LOT, so yes, this is typical.
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I would test at the loudest listening position you use. If there is a tiny bit of hum, that is allowable as you would only hear it between tracks. But you probably won't hear it between tracks.
All the way up is some reference audio reviewers threw out there. And it is dependent on a lot of factors.