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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 48

post #706 of 1579
2/9/13 at 3:07pm
Quote:
Originally Posted by mab1376 View Post


You may just need to clean the contacts, check eBay for deoxit.

Thanks for your suggestion. I have already scrubbed the pins with a soft stainless steel brush and then with a soft brass brush but that didn't make any difference. I have deoxit, but as the brushing didn't help, didn't really think deoxit would either. Will give deoxit a try.... However, I am beginning to think that the tubes are simply defective... bummer.....  

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post #707 of 1579
2/9/13 at 3:58pm
Quote:
Originally Posted by gibosi View Post

Thanks for your suggestion. I have already scrubbed the pins with a soft stainless steel brush and then with a soft brass brush but that didn't make any difference. I have deoxit, but as the brushing didn't help, didn't really think deoxit would either. Will give deoxit a try.... However, I am beginning to think that the tubes are simply defective... bummer.....  
That's possible, good luck.
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post #708 of 1579
2/9/13 at 3:58pm
Quote:
Originally Posted by gibosi View Post

Thanks for your suggestion. I have already scrubbed the pins with a soft stainless steel brush and then with a soft brass brush but that didn't make any difference. I have deoxit, but as the brushing didn't help, didn't really think deoxit would either. Will give deoxit a try.... However, I am beginning to think that the tubes are simply defective... bummer.....  
That's possible, good luck.
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post #709 of 1579
2/9/13 at 5:44pm
Quote:
Originally Posted by DutchGFX View Post

I have a huge problem! I just received my MKiii, and I hooked it up to my e17 with L7 for line out, I think, and my Q701's have REALLY DISTORTED BASS! It also is distorted on my K240 MKii, and I didn't try my sextetts but I assume it's the same. Why is this, do I need to burn them in to get rid of the distortion? It sounds very boomy, and muddy, not detailed, and does not blend with the music, aka, distorted. Help please biggrin.gif thanks guys

Are you sure you have the right settings for the tubes you are using (read manual) and you can also clean the contacts on your tubes with isopropyl alcool 90% proof

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post #710 of 1579
2/9/13 at 7:38pm

Does anyone have any experience with Philips Miniwatt 408As?

 

http://www.nostubestore.com/2012/08/philips-miniwatt-ts62-6028-408a.html

 

These are somewhat expensive little buggers but with gold pins they sure look real tempting!

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post #711 of 1579
2/10/13 at 7:55pm

Would like to share a rather scary occurence.

 

Today the left channel on my MKII completely went dumb/out. Tried swapping tubes, checked switches and everything but nothing fixed it. Definitely was sure it was the amp since I tried different outputs on my DAC and other headphones.

 

Somehow it magically came back. I'm hoping that its an isolated occurence but will report back if it happens again.


Edited by junkimchi - 2/10/13 at 8:04pm
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post #712 of 1579
2/10/13 at 7:59pm

One thing you did not mention for the next time is your source connections

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post #713 of 1579
2/11/13 at 11:03pm

Ok the dead left channel just happened to me again. But then it got fixed again as the amp warmed up a bit. Is this normal? Does this happen to anyone else?

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post #714 of 1579
2/12/13 at 6:33pm

UPDATE: Turns out it wasn't the amp but actually my D1. Swapped and reseated the OPAMPs and the problem was fixed. I guess it was the superior being's way of telling me I should know the insides of my DAC. 

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post #715 of 1579
2/12/13 at 8:08pm

I knew that your LD was not the issue. I had DAC problems before and my LD's are a bit picky on what DAC source works the best.

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post #716 of 1579
2/13/13 at 12:47am
Hey John, I have another quick question about your GEC CV4014, if you don't mind.

I just realized that of the two GECs I've been using (pretty much my favorite tube now, right up there with the CV4015), one produces a noticeable flash when switched, and I can't *see* a flash in the second one, but it could be hidden by the silver screening; it's hard to tell. My closest CV4014 made 2 years earlier flashes too. I'm just wondering if my two non-NOS GECs are exactly identical or not, or if say one is dying.

So, could you possibly tell me if yours flash when switched on?

Btw, I do strongly encourage testing those tubes, they are much more punchy and powerful than the EF92 (and 6ak5) and have a great bass thump and liquid mids that work miracles with orthos (HE-500 in my case).

And also, to the person who tried some 6n1p as power tubes on the LD, I really wouldn't do that... Same pinout does not indicate compatibility and in this case, apart from heater voltage and being a double triode there isn't much in common with the 6n6p... Still, I'm curious to know if it even worked and how it sounded.
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post #717 of 1579
2/13/13 at 2:48am

Yep, my second set of the GEC tubes the left will flash and the right does not.

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post #718 of 1579
2/13/13 at 2:56am
Quote:
Originally Posted by john57 View Post

Yep, my second set of the GEC tubes the left will flash and the right does not.


Interesting. So I shouldn't worry about that I guess, as both tubes I use sound the same, and great.

 

Those are your "XF" date coded tubes right?

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post #719 of 1579
2/14/13 at 6:32am
Quote:
Originally Posted by Audiofanboy View Post

Hey John, I have another quick question about your GEC CV4014, if you don't mind.

I just realized that of the two GECs I've been using (pretty much my favorite tube now, right up there with the CV4015), one produces a noticeable flash when switched, and I can't *see* a flash in the second one, but it could be hidden by the silver screening; it's hard to tell. My closest CV4014 made 2 years earlier flashes too. I'm just wondering if my two non-NOS GECs are exactly identical or not, or if say one is dying.

So, could you possibly tell me if yours flash when switched on?

Btw, I do strongly encourage testing those tubes, they are much more punchy and powerful than the EF92 (and 6ak5) and have a great bass thump and liquid mids that work miracles with orthos (HE-500 in my case).

And also, to the person who tried some 6n1p as power tubes on the LD, I really wouldn't do that... Same pinout does not indicate compatibility and in this case, apart from heater voltage and being a double triode there isn't much in common with the 6n6p... Still, I'm curious to know if it even worked and how it sounded.

Hi Audiofanboy,

Yes the 6n1p works as power tube on mkii. Initially i thought that it sounded smooth will slikier highs, clearer presentation than the 6n6p. But after a while of listening the effect was actually 6n1p not having enough power to drive grado 225i. It sounded ok when the volume knob was at around 9 oclock, but when turned to higher volume sound started to distort especially the bass, and the level of loudness did not change much. Like amp is losing power.

Temperature of the mkii when running on 6n1p as power tube after 2 hours remained normal. Anyone may try to see the effect of 6n1p, but i personally do not think it's worth. But if there is anyone who actually willing to try it, please tell us your results and thoughts.

Afterall tube rolling is in deed addictive... Happy rolling....
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post #720 of 1579
2/14/13 at 7:01am
Quote:
Originally Posted by torara View Post


Hi Audiofanboy,

Yes the 6n1p works as power tube on mkii. Initially i thought that it sounded smooth will slikier highs, clearer presentation than the 6n6p. But after a while of listening the effect was actually 6n1p not having enough power to drive grado 225i. It sounded ok when the volume knob was at around 9 oclock, but when turned to higher volume sound started to distort especially the bass, and the level of loudness did not change much. Like amp is losing power.

Temperature of the mkii when running on 6n1p as power tube after 2 hours remained normal. Anyone may try to see the effect of 6n1p, but i personally do not think it's worth. But if there is anyone who actually willing to try it, please tell us your results and thoughts.

Afterall tube rolling is in deed addictive... Happy rolling....


Fascinating, though I wouldn't try it myself ;) .

 

After checking the datasheet for 6n1p (I was thinking 6n23p / 6922 type tubes, used more as a driver tube), it's not that far apart from a 6n6p in its basic electrical characteristics; not exactly replaceable but I understand why it didn't explode or anything.

 

Still wouldn't try it though.

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