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.

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….

rogier wrote:

It could be dirt (dust) in the aircaps..

Markus wrote:

... but did you clean your needles? And does this happen on all records or just specific ones?

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.

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

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.

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?

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.

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.

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

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?

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.

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.

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