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11-16-2011 Post does not mapped to Knowledge Tree
Markus
Posts 68
Joined on 03-07-2007

Post #: 141
Post ID: 17375
Reply to: 17373
Too obvious perhaps ...
fiogf49gjkf0d
 Romy the Cat wrote:
Now at higher it goes and as louder it gets it has more and more almost some kind of mechanical resonances overlying over sound. Dead tubes would not be doing it.


... but did you clean your needles? And does this happen on all records or just specific ones?
11-16-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 142
Post ID: 17376
Reply to: 17372
Hum points
fiogf49gjkf0d
 Romy the Cat wrote:
Yes, the layout kind of not optimum. You might try to lay the transformers sidewise and to make the RCA atop, above the transformers. Still, I hope you understand that your hum has very little to do with layout. Properly grounded unit shell has no noise in open incisures. You need to play with grounds.  I usually use by-pass ground techniques – never failed on me. One you find a proper grounding then whatever you will do with the corrector will produce no noise. BTW, I did ask anybody to mane the uploaded images identifiable, so please….


Yes, I understand all your points. I don't think I have any ground loops though--I tried your ground bypass technique and it didn't change anything so far. Apologies for the pic--I've uploaded it automatically and then realized that it was not named (in your gallery it's impossible to rename the file).



Cheers,
Jarek
STACORE
11-16-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 143
Post ID: 17377
Reply to: 17376
Beats and pieces.
fiogf49gjkf0d
 rogier wrote:
It could be dirt (dust) in the aircaps..
Hm, a good point, I never consider how dust in aircaps might sound. I presume that it will be no difference as dialectic is air anyhow, it is beside the point that there. Still, the sonic difference between “clean” air caps and dirty is certainly not know to me. Nevertheless, I do not think that it is due to dirt in air caps as it would be developing slowly. My problem appears all of the sudden. Well, it might be a single piece of dirt all of the sudden shorted two aircaps sheets? In this care it would be juts drop in capacitance with change of RIAA cure. Sure, it is not hard to blow the aircaps. Juts to be on the save side I will run tonight inverted RIAA sweep and see if I am still flat. Subjectively I do not recognize any in frequency response in the records I know and I am very sensitive to it. The anti-RIAA sweep sill would be a good indicator…

 Markus wrote:
... but did you clean your needles? And does this happen on all records or just specific ones?
I always clean needles. I even removed the headshells and inspected the needle and cantilevers as I thought that some metal dust was somehow attacked in my room and jammed suspension. Nope it was not the case and my cartridges are fine. The effect is happening on all records.

 N-set wrote:
Yes, I understand all your points. I don't think I have any ground loops though--I tried your ground bypass technique and it didn't change anything so far.
Try to short the signal to ground at different points of the corrector and see how noise disappears. Literally go over the circuit from front to the end before and after each element and see if shoring it this specific location affects noise. If the specific location cares DC then use cap to short the signal. Does the corrector have noise without the transformer? If not then you need to find a proper interface between transformer and corrector. Most common problem (if your transformer is properly shielded that most likely not be the case) is that people use dual mono transformer with stereo correctors.  I think it is what you do, I do it as well. So, to deal with it you need to connect grounds of your transformer together. Where to connect them and how to connect them to corrector is a big subject but for beginning to short the grounds of RCAs would be a good start. I do not know what Pieter use for shielding if it is one layer of mu-metal then it is not enough. BTW, a transformer has to have some room in the shielding can and some empty space around itself. The shielding layer must be separated by air and do not lay over each other. Anyhow, I am sure you will find the problems. It is impossible to remotely debug ham….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-16-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 144
Post ID: 17379
Reply to: 17377
What else?
fiogf49gjkf0d
Hm, I took the anti-RIAA signal converted and run CD player into the phonostage. The RIAA curve was fine and the effect of the HF volume and frequency-depended quantization did not expose itself. So, it looks like the phonostage is not a problem after all. That is very good and… very bad as I have nothing to blame now. I did played with mono tonearm last week but it sound fine now, with no quantization and I think the stereo arms did sound fine after I finish with it. What the hell has happen with me stereo arms! How two arms might get “broken” like this if then never were even touched? Is it in cartridges? Is it tonearms (both at the same time!!!) Is it something environmental?  The cables from both arms come to the same phonostage at the same entry jacks… is it possible that both cables pick some interference from something? The entire analog setup with max out volume has no more noise then it usually has, the noise is VERY low. You need to stay right at the mouth of horn to hear something. It is with 83dB gain in phonostage and 109dB sensitive acoustic system at… max out volume.  My normal listening level is good 50dB down, so it is no noise or interference in cables. What else?


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-16-2011 Post does not mapped to Knowledge Tree
JJ Triode
Posts 99
Joined on 09-12-2007

Post #: 145
Post ID: 17380
Reply to: 17379
Suggestion for the phonocorrector problem
fiogf49gjkf0d
Romy,Try running the left and right signals from the stereo arms, one at a time, into the known-good mono phonocorrector.  If the problem is not present then you know the stereo corrector is to blame.
Are both left and right channels in the stereo corrector sounding bad?  Then check the power supply (unless it is a dual-mono supply, then it is very puzzling.)  If the power supply is in a separate chassis, can you run the stereo corrector from the mono corrector's PS?
As Paul said, clean and tighten all cable connections, including in the AC and PS umbilicals.JJ
11-16-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 146
Post ID: 17381
Reply to: 17380
I do not think that it is electrical.
fiogf49gjkf0d
 JJ Triode wrote:
Romy,Try running the left and right signals from the stereo arms, one at a time, into the known-good mono phonocorrector.  If the problem is not present then you know the stereo corrector is to blame.
Are both left and right channels in the stereo corrector sounding bad?  Then check the power supply (unless it is a dual-mono supply, then it is very puzzling.)  If the power supply is in a separate chassis, can you run the stereo corrector from the mono corrector's PS?
As Paul said, clean and tighten all cable connections, including in the AC and PS umbilicals.JJ
Actually I do not blame phonocorrector anymore. If running the inverted RIAA signal across the corrector sounded fine than the phonostage is not guilty. Yes, both right channels sound identically bad. I do not believe that it has to do with anything electrical at this matter. It is mechanical as it has almost some kind of HF resonance texture. It feel like somebody play a loudspeaker that lays on a floor with drivers up and then spread super fine led shots over the drivers…. So, I do not think that it is electrical, I hope it is not psychological….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-16-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 147
Post ID: 17382
Reply to: 17377
Veggie ham
fiogf49gjkf0d
I'm slowly getting somewhere. Disconecting transformers did bring the ham down, but to my surprise
not exactly to the level where it was before-it's unfortunately stronger.
And all this after my heroic removal of Holcos from the grids of V2.
The ham is there, its level varies from annoying (standard) to only lightly hearable depending on the orienation
of the signal and PS boxes (the PS box is closed, the signal is still open). Strangly it also decreases a bit
when I touch the case, possibly indicating a poor grounding of the cases, which is not the case given my religious
approach to it...the fight with ham continues, i'm still not in the position to start wityh the transformers...
BTW they seem like one layer of mumetal, i glued them to the Cu plate with silicone, but the cases wanted to be
grounded (at least this is what I inferred)--hence a strips of braid in the picture.

Cheers,
Ham-Set



Cheers,
Jarek
STACORE
11-17-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 148
Post ID: 17384
Reply to: 17382
Do phonocorrector first then transformers.
fiogf49gjkf0d
 N-set wrote:
I'm slowly getting somewhere. Disconecting transformers did bring the ham down, but to my surprise not exactly to the level where it was before-it's unfortunately stronger. And all this after my heroic removal of Holcos from the grids of V2. The ham is there, its level varies from annoying (standard) to only lightly hearable depending on the orienation of the signal and PS boxes (the PS box is closed, the signal is still open). Strangly it also decreases a bit when I touch the case, possibly indicating a poor grounding of the cases, which is not the case given my religious approach to it...the fight with ham continues, i'm still not in the position to start wityh the transformers... BTW they seem like one layer of mumetal, i glued them to the Cu plate with silicone, but the cases wanted to be grounded (at least this is what I inferred)--hence a strips of braid in the picture.
Well, you need to get rid of transformers and to make your phonocorrector to have no noise of any kind with any transformers. From MM level you need to have no more then 1-3mV AC at output and absolute not noise. After you do it, then you can add transformers to start to play with it.

Yes, one layer of mumetal is not enough. Theright configuration is 4 layers separated by space: mumetal, aluminum, copper and steel. Each of the layer works with own shielding and it is very good to give for transformers at list 2-3 inches or more of free space around them before the first internal layer. Mumetal might be eliminated if steel is very think, I would say with 1/3-1/2 inch you might stat do not worry about mumetal.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-18-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 149
Post ID: 17388
Reply to: 17379
Holly idiocy!
fiogf49gjkf0d

 Romy the Cat wrote:
Hm, I took the anti-RIAA signal converted and run CD player into the phonostage. The RIAA curve was fine and the effect of the HF volume and frequency-depended quantization did not expose itself. So, it looks like the phonostage is not a problem after all. That is very good and… very bad as I have nothing to blame now. I did played with mono tonearm last week but it sound fine now, with no quantization and I think the stereo arms did sound fine after I finish with it. What the hell has happen with me stereo arms! How two arms might get “broken” like this if then never were even touched? Is it in cartridges? Is it tonearms (both at the same time!!!) Is it something environmental?  The cables from both arms come to the same phonostage at the same entry jacks… is it possible that both cables pick some interference from something? The entire analog setup with max out volume has no more noise then it usually has, the noise is VERY low. You need to stay right at the mouth of horn to hear something. It is with 83dB gain in phonostage and 109dB sensitive acoustic system at… max out volume.  My normal listening level is good 50dB down, so it is no noise or interference in cables. What else?
Well, I have fixed my analog.  It has no relation to phonostage but as long I did blamed the phonostage above than I post resolution in the same thread. The reason was my dust tonearm. I do not have an idea why it did it bit as long I remove it the problem disappear. I have two dust tonearm on my TT the light-duty with brash and heavy duty with brash and roll.  The light-duty dust tonearm was installed on the armboard of my Second stereo arm. Of cause there was nothing vibrating or shaking on that dust-arm but apparently my TT did not think so, even thogh I did not even use this dust-arm with stereo catrighes. If somebody would tell me that this light dust-arm installed on very platter and on TT like Micro 8000 would be able to effect anything I would not believe.  However, the fact is fact – putting it back I got my “quantization” of sound back and removing it did remove the quantization. The mono arm apparently did not pick up the responses from the dust-arm as the mono arm instated on the other side of the TT or perhaps because mono cartridges are more immune against all of this.

Again, it is absolutely absurdity but it is what it is. BTW, here is a good concussion from the story – it shall be nothing, absolutely nothing, which might be sitting on the TT platter. I have a luxury of having wide and comfortable platter on which I have a habit to put a lot of superfluous crap. Not when I do it I would think twice, or at least listen once.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-20-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 150
Post ID: 17392
Reply to: 17384
Yes sir
fiogf49gjkf0d
 Romy the Cat wrote:
Well, you need to get rid of transformers and to make your phonocorrector to have no noise of any kind with any transformers. From MM level you need to have no more then 1-3mV AC at output and absolute not noise. After you do it, then you can add transformers to start to play with it.


It wants to be shielded. I've lined the inside of the signal steel/alu case with a copper foil (for furtherreference 0.3mm foil is way
too thich and hard to work with), closed the case and the ham is gone, my phono is vegetarian again!
No minor changes in layout could kill the ham with case open---the pickup from the PS was too strong
(my cabel is very short, 60cm of f...cking stiff cardas twisted pair f...ck! I'll double it soon). This makes me think to line the
inside of the PS case with the foil too so that it does not vomit the garbage all over tha place...

Now the fun begins with connecting the transformers...let's see...

Cheers,
Nset




Cheers,
Jarek
STACORE
11-20-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 151
Post ID: 17393
Reply to: 17392
I think your game is not over.
fiogf49gjkf0d
Hmmmm. Nset I will tell you something that will disturb you but it is what it is. If you did not use transformers and your phono was noisy and shielding did help it to be not noisy then you do not a proper grounding in your phonstage. The non- shielded phonstage might have some minor noise but it will be upper range noise and shielding, or putting it into an enclosure, will help. If you have num then it has nothing to do with shielding but only grounding. If your shielding helped against num then it was not because shielding but because you inadvertently change something in grounding. It is my believe and it is my experience that a phonstage with properly implemented grounds (from perspective of hum) does not need any shielding or even enclosure for this meter. Yes, shielding of cause will help but to a VERY minor scale (for hum) and only if you are willing to place it right next to aggressive polluters (like TT motors etc…)

The Cat, not Sir.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-20-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 152
Post ID: 17395
Reply to: 17393
More ham
fiogf49gjkf0d
I see the point, thanks a lot for your comments. Playing with the phono I've somehow come to a conlusion (possibly wrong)
that my ham is an electrostatic air pick-up from the PS. During the operation both PS and signal boxes are very close
together and the hum depends on the relative orientation of the two and gently fades away when switched off.
I must say though I have not done your trick with shorting the stages (only shorted the input) as it's difficult with this
design: 2nd stage is fixed bias, DC coupled to 3rd. I did pay a lot of attention to the ground, so actually cannot
imagine having a ground loop anywhere (I guess this is what you are referring to as improper grounding?).
 
However, if I lift the ground I get a horrible pick-up, which I think is in turn magnetic (it desappears instantly
when I switch the phono off). THis is actually something that worries me and perhaps indicates that
you may be right: why lifting the ground leads to such a drastic change?
 
Cheers,
N-set



Cheers,
Jarek
STACORE
11-20-2011 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 153
Post ID: 17397
Reply to: 17395
Route(s) to Ground
fiogf49gjkf0d
The ideal "star" grounding plan is seldom realized in practice, for lots of reasons. For one thing, it takes serious concentration to really think it through. As I have said many times, it is often useful to have a "bleeder" on the chassis, and this works better if it runs uninterrupted to a dedicated ground rod rather than via the mains neutral or ground. Again, neutral and ground share a bus at the main (service) box, in any case, and often before that in a sub-panel, or even in outlet or junction boxes, even though this is not good for hi-fi (nor is it safe...).

The phono [pre]amp exacerbates both parasitic and self noise both just because it boosts a small signal so well.  Sure, any EMF can harbor and/or effectively generate noise that gets picked up by the gain circuitry, in addition to generic EMI and RF. Likewise, current may be "stacked" internally due to varying ground potential, especially between gain stages, not to mention the loops we always figure out the hard way.

Lastly, not saying it is this way for you, but I have also been quite peeved when replacing a special $$$ tranny with someting "less special" cured the hum immediately!

Best regards,
Paul S
11-21-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 154
Post ID: 17404
Reply to: 17397
Grounding arrangement
fiogf49gjkf0d
The grounding I have employed is a mixture of a "local star" and GND plane (I've obviously copied it from the Cat).
I did pay a lot of attention not to have loops. Here is my grounding scheme. I wonder if there are any obvious errors?

Nset_834P_GND.JPG

There is a switch breaking lifting the GND plane from the chassis. If I lift it I get a horrible pickup, I think magnetic
100Hz from the PS (the hum disappears instantly when switching all off).
The connection between the signal and the PS box is via a shield (braid) on the umbilical.
Then at PS, the chassis is connected to the GND
pin of the IEC power inlet (for the time of experimentation I connect to the power ground).

Actually, connecting the scope across 470k output resistors (at the RCA's) the pick up with the phono switched off
is of the same amplitude as the ham with the phono switched on (but for eample the pick up on the 2M grid is negligable).

Cheers,
N-set






Cheers,
Jarek
STACORE
11-22-2011 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 155
Post ID: 17405
Reply to: 17404
Ground Thoughts
fiogf49gjkf0d

Is the "ground plane" in this case literally a sheet of copper that you run all the grounds to? If so, this may be overkill on the one hand and an antenna/noise magnet/generator on the other hand, and/or it may well make for ground loops. It is usually sufficient to have a ground "bus" that is not connected to the chassis, and this goes out on the neutral wire. Parts should not directly touch the copper sheet or the chassis; stand them off mechanically and electrically. The chassis and your IC shields can use the "dedicated" ground. The "house" ground is lifted at the chassis/not used for the phono stage. You are using shielded IC, right? Bleed the shields from the upstream end only (and leave the downstream end loose; do not ground shields at both ends...).

Good luck.

Best regards,
Paul

11-22-2011 Post does not mapped to Knowledge Tree
AlexBerger
Israel, Beer Sheva
Posts 20
Joined on 04-19-2010

Post #: 156
Post ID: 17406
Reply to: 5856
0A2 Question
fiogf49gjkf0d
Hello Romy,

What brand of 0A2 do you use in your phonostage?
I used RCA, but after 1.5 years of work it began to spark when phonostage is switched on.
I tried Siemens, Mazda and now Sylvania 0A2.
Siemens has "disco sound", without mids, just metallic highs and punchy bass.
Mazda has strong sweet coloration with accent to upper mid and week bass.
Sylvania sounds good, actually more interesting than RCA did. But vocal doesn't sound smooth enough.
Maybe it needs some break-in time?

Regards,
Alex.   

11-22-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 157
Post ID: 17408
Reply to: 17404
Where is the Bolt?
fiogf49gjkf0d
N-set, it is difficult to say anything without seeing the circuit. I think that you did not exactly my version but made some modifications; I do not know/remember what they were.  The major think that I see at your picture is that your main grounding point is too far from where I accustom to have it. In my view the  main grounding point, the location where everything need to come together, including the negative from filament and contact o chasses is  the spot where you phono cable enter the box. Right next to RCA jack you need to have a big bolt driven into chasses and to this bolt everything needs to go. When you do ground bypassing and trace the source of your hum then you need to bypass everything in the respect to this bolt. I do not insist that this is how it always needs to be done. I am not an experience equipment builder – you have much more experience and knowledge. But how I described I bolt all my 4 phonostages and I never had any problems with noise, I presume that something I did right.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-22-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 158
Post ID: 17409
Reply to: 17406
Gas tubes in the phonostage
fiogf49gjkf0d

 AlexBerger wrote:
Hello Romy,

What brand of 0A2 do you use in your phonostage?
I used RCA, but after 1.5 years of work it began to spark when phonostage is switched on.
I tried Siemens, Mazda and now Sylvania 0A2.
Siemens has "disco sound", without mids, just metallic highs and punchy bass.
Mazda has strong sweet coloration with accent to upper mid and week bass.
Sylvania sounds good, actually more interesting than RCA did. But vocal doesn't sound smooth enough.
Maybe it needs some break-in time?

Alex,

They all are good questions

I have published a short survey: “150V Gas Tubes survival guide.” at:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=2792

where I did explore hot the gas tube impact sound. However, that was in context of Melquiades amplifier, where the gas tubes drive bias – MUCH more sensitive element then anode supply in my view. Regardless if it was more sensitive or not I think the topological difference would make my experience with Melquiades’ use of gas tube not applicable to use of gas tubes in my phonostage.

I never made any tube roiling in the PS of phonostage, I should but I did not. I put in there Telefunkens and did not try anything else, the Telefunkens were not my the best choice with Melquiades, but since Telefunken tube are very reliable and I have no easy access to phonostage’s PS I figured that Telefunken will be a reasonable choice if I am not going to see those tubes for very long time, preferably never again.

Telefunken most likely made by Siemens, or versa versa, so it is possible that your Siemens and my Telefunken are the same tubes rebranded. Sylvania are very very good tubes, I always like them, in fact I use special Sylvania 12AX7 in the second stage of my “End of the life phonostage”. My the most beloved 150V gas tube is Amperex. They have not flat shields like all other tube but many small holes in the shield that make them to look very different and they do sound in my estimation much bettered. But again, it was in Melquiades, who knows how they will sound in phonostage.
 
The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-22-2011 Post does not mapped to Knowledge Tree
AlexBerger
Israel, Beer Sheva
Posts 20
Joined on 04-19-2010

Post #: 159
Post ID: 17410
Reply to: 17409
"End of Live" tube set
fiogf49gjkf0d
Romy,

Thank you.

I think I should to give some break-in time to Sylvania 0a2.
50 hours is enough?

Previously I used in my EAR the next set of tubes ECC83: 1-Amperex (red print), 2-Amperex (red print), 3-Sylvania 7025 (yellow print).
When I built "End of Live", I used tube set exactly lake you do: 1-Telefunken (smooth plate), 2-Sylvania 7025 (yellow print), 3-Telefunken (smooth plate).
(But my Sylvania 7025 is not specialty strong...)
Now I changed Sylvania 7025 to Amperex (red print). IMHO the sound is steel natural and well balanced but more refined.
11-22-2011 Post does not mapped to Knowledge Tree
N-set
Gdansk, Poland
Posts 609
Joined on 01-07-2006

Post #: 160
Post ID: 17411
Reply to: 17405
GND plane
fiogf49gjkf0d
 Paul S wrote:
Is the "ground plane" in this case literally a sheet of copper that you run all the grounds to? If so, this may be overkill on the one hand and an antenna/noise magnet/generator on the other hand, and/or it may well make for ground loops.


Oh, this is a very controversial statement Paul! The 2D sheet of thick copper (or in my case actually semi-3D as the Cu is 1.5mm thick)
has vanishing inductance and resistence. Thus it's antena action is zero so is it's resistance in any "ground loop". Thus no loop.
Think that various induced currents have a much more space to distrubute themselves properly. I have zero experience with RF,
but, the common knowledge there says a 2D sheet provides an ultimate ground.


 Paul S wrote:
It is usually sufficient to have a ground "bus" that is not connected to the chassis, and this goes out on the neutral wire. Parts should not directly touch the copper sheet or the chassis; stand them off mechanically and electrically. The chassis and your IC shields can use the "dedicated" ground. The "house" ground is lifted at the chassis/not used for the phono stage.

Again, bus is semi 1D, it has higher self inductance than a plane and so it's antena action is stronger. Yes, all the parts are lifted from the GND plane/chassis. I use house earth for the safety of experimentation-I don't want to electrocute myself before I finish the phono.

Cheers,

Nset





Cheers,
Jarek
STACORE
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