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Post by Deleted on Sept 12, 2015 15:06:23 GMT
I recently had to reluctantly sell off a few pairs of my headphones meaning I'm now left with only low impedance 'phones. As a result my Ember isn't getting the love or use it deserves so I've decided to sell it on at a special price for DIYAH members only. Will be closer to 'market value' if it gets listed elsewhere but I'd rather sell here in the knowledge it's going to a good home I'm the second owner having bought the Ember from a fellow head-fier approx. 3 months ago. I believe he originally bought it new back in March this year. In very good condition complete with worldwide power supply (110-240v) and a UK kettle lead. If you're overseas then you'll need to replace the kettle lead with one suitable for your country but the power supply itself will work just fine. Acrylic top plate & bottom plates (top is clear / bottom is black). The stock JJ ECC82 is also included and works fine but does sit a bit squint in the socket, which I'm told it's done from new. I've tried a number of other tubes and they all sit perfectly upright so can confidently say that the Ember's tube socket itself is fine. One other thing to mention is that I do get some slight noise from the volume pot if I turn it quickly when no music is playing. With music playing it isn't noticeable but I like to be upfront about things. I asked Frans about it recently and it appears to be quite normal with the Ember 1's volpot: link (edit: please also read posts below for more info).When I sell an item the most important thing to me is that you are pleased with your purchase. To this end I'm more than happy for the buyer to 'audition' the Ember for a week from the date of arrival and if for any reason you're not 100% satisfied you can return it for a full refund - no questions asked (unless you smear it in jam and paint it green). I'll also cover all return postage costs if you're in the UK or make a contribution if further afield In terms of posting I may need a couple of days to find a suitable box for posting, as I like to package stuff up properly to ensure it arrives the same way it left. I will post outwith the UK if you cover any extra shipping costs involved (I'd estimate £6 or £7 to EU countries and perhaps a bit more for R.O.W.) - PM me and I can check exact costs for you. Make no mistake this is a truly wonderful amp and I will genuinely be sad to see it go. £115 including UK delivery (DIYAH price)
Any questions please just ask!
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Post by Deleted on Sept 12, 2015 15:25:48 GMT
The JJ ECC82's tend to have a slightly rounded bottom to the glass which is why it might not sit entirely perpendicular. Not a problem.
The scratchy volume pot issue is only because the output capacitors have been by-passed. With them in circuit it goes away. Again, no big deal.
Good luck with sale but I doubt you need luck as that's an excellent price.
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Post by Deleted on Sept 12, 2015 15:32:53 GMT
Cheers Gordon.
That would make sense. The pins don't seem bent so suspecting it's just the way they protrude from the glass.
The noise I mentioned occurs when the caps aren't bypassed but Frans says that can happen. It's lower level than the scratch you get when you bypass the caps, which iirc was still evident when music is playing (only when turning the knob of course!).
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Post by Deleted on Sept 12, 2015 15:50:22 GMT
It's probably dust then. Have you tried screwing it between min & max to see if it goes away? That actually happened to me last night. Sweeping left to right removed it completely.
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Post by Deleted on Sept 12, 2015 16:12:13 GMT
Don't think it's dust as I've tried turning the knob a few times and unscrewing it and giving things a wipe. It's been evident since I received the amp and hasn't worsened over time so don't think it is symptomatic of anything untoward.
The noise really only manifests itself when the knob is turned quite quickly when no music is playing esp. when approaching max volume. Slower turns of the sort you'd likely make when listening to music tends to result in no noise from the pot. So in normal usage it's not something that is really an issue at all.
Here's what Frans had to say about it:
"The scratchiness of the volpot can also be heard with the input cap not bypassed. It is very faint though and is only heard when no music is playing. Ember 2 has an extra resistor which prevents this BUT with SOME tubes it is possible background hiss becomes audible. Modification is possible. When I have some time I can do those mods to my Ember and make a tutorial."
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solderdude
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Post by solderdude on Sept 12, 2015 21:12:38 GMT
I can add to this that it is also very tube dependent.
It's not dust, the potmeter is as good as hermetically closed.
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Post by Deleted on Sept 12, 2015 23:42:02 GMT
Thank you for the input Frans. I haven't really noticed any difference between tubes myself but haven't rolled too many. Just had a listen again and it actually sounds like it's only the left channel that exhibits any noise (not very loud) - does that change your thoughts or can one channel sometimes be 'affected' more than the other? As previously mentioned it is only evident with no music playing and once the volume has been set the noise stops immediately. Equally fine adjustment of the volume knob doesn't result in any noise through either channel. It's only relatively quick turns that generate the 'crackle' sound, which does seem to point to the potmeter rather than anything else as presumably it'd otherwise always be present. I personally found this a non-issue but appreciate that it could be a concern for potential buyers (when you can't hear something for yourself molehills can seem like mountains), so it's always reassuring for all parties to get an expert's take on things. Cheers again! ---- Just to add that I want folk to be 100% satisfied with anything I sell them and I'm always happy to offer a full refund if they're not. Zero hassles and no questions asked
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solderdude
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Post by solderdude on Sept 13, 2015 16:58:27 GMT
If you want you can send it to me and I will modify it and if needed replace the pot. It is always possible a component fails.
When it only is present in one channel and independant of tubes that could point to a dodgy pot.
Does it happen with nothing connected to the input as well ?
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Post by Deleted on Sept 13, 2015 18:59:15 GMT
Thanks Frans.
Sounds like there could potentially be more may be afoot than the usual pot noise we discussed, so probably best I remove the Ember from sale whilst we get to the bottom of things.
I was wrong in my earlier comment about the 'crackling' noise only coming from the left channel. Whilst predominantly from the left it's actually also present in the right channel, only less audible. This noise only occurs when the volume knob is turned quickly and happens whether I have a source connected to the RCA input or not.
With RCA cables connected the amp is completely silent when no music is playing and I am not fiddling with the volume knob. If I remove the RCA cables then I hear a low level electrical 'hum' which gets steadily louder as the volume is increased. This hum is present at all times but ceases as soon as I plug one or both RCA interconnects back in. Not sure if that's what you would expect or not?
As I say the pot noise really isn't something that I've found problematic, so if you think it's unlikely to worsen I'll probably just mothball the Ember until I next own a suitable headphone and then enjoy it 'as is'. However, if you think it might be indicative of something more serious then it would definitely make sense to take you up on your offer to have a look at the amp and make any mods or repairs you feel are necessary. If you feel it's worth further investigation would it be okay to discuss via PM?
Thanks again for all the help. It's much appreciated!
Best, Mark
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solderdude
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Post by solderdude on Sept 14, 2015 6:17:12 GMT
Hi Mark,
I don't think anything is wrong with it. However, if you want the 'scratch mod' to be performed then P.M. me.
The noise you hear when adjusting the volpot is caused by eletrons leaking through the grid. The change of resistance (when turning the pot) while the current remains the same equals a varying voltage. That voltage change (on the input) is what you hear.
The mod consists of adding a resistor so the resistance the grid 'sees' doesn't vary as much any more. This lowers the 'scratch' to levels below the audible limit (its still there but greatly reduced).
the catch is ... SOME tubes have a much higher grid leakage then others. When this is the case a higher grid current + higher resistance = higher noise amplitude. So... with SOME tubes this mod trades in scratchy noises while adjusting to a higher noise floor.
The hum with open inputs is normal b.t.w. I just wanted to know for sure a DC on the input didn't cause the scratchiness, which it can.
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Post by Deleted on Sept 14, 2015 20:29:40 GMT
Hi Frans.
That's a weight off!! I really can't thank you enough for all your help 'troubleshooting' things and for the very clear explanation of the reasons why the scratch occurs.
It sounds like the mod is a bit of a double edged sword if it potentially elevates the noise floor of some tubes. Having heard amps with an audible noise floor in the past I have to say that some volpot scratchiness is a minor inconvenience by comparison. I do appreciate the offer though.
Thanks also for confirming the hum with open inputs is normal.
Best wishes, Mark
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Post by tunkejazz on Sept 22, 2015 11:18:37 GMT
So...have you sold it? :-P
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Post by Deleted on Sept 22, 2015 14:53:43 GMT
So...have you sold it? :-P Possibly. Should know for sure in the next few days.
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Post by tunkejazz on Sept 22, 2015 15:04:38 GMT
So...have you sold it? :-P Possibly. Should know for sure in the next few days. Let me know if you haven't, I am interested...also in a polaris.
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Post by Deleted on Sept 22, 2015 15:39:04 GMT
Possibly. Should know for sure in the next few days. Let me know if you haven't, I am interested...also in a polaris. Okay, will do Can't help you with a Polaris though I'm afraid....wouldn't mind trying one myself.
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