I'm in the "slightly sharp" part of the burn in process with mine.
Doesn't last long but I expect that it's particularly obvious on the end of a 2M black!
BTW, don't rush to fit the MultiFETs as in MM mode you don't use them any way [emoji2359] [emoji1787]
Mine pictured below with precariously positioned Russian PIO caps....bloody great they are too.
Interesting. I'd not realised multifets were optional!
The 2M can be 'honest' in its presentation, everything on the disc gets sent to the amplifier, and the Shibata seems to be the world's most effective tool for scraping detritus out of a groove to boot. But I like the Ortofon house sound. Hung from an Audiomods S6 it sounds good to me, and tracks brilliantly.
Those caps are *huge*, been googling and there seem to be a lot of low value PIO, but not so much at 2/2.2uf. You have a reliable supplier or just took a chance on it?
The 2M can be 'honest' in its presentation, everything on the disc gets sent to the amplifier, and the Shibata seems to be the world's most effective tool for scraping detritus out of a groove to boot. But I like the Ortofon house sound. Hung from an Audiomods S6 it sounds good to me, and tracks brilliantly.
Those caps are *huge*, been googling and there seem to be a lot of low value PIO, but not so much at 2/2.2uf. You have a reliable supplier or just took a chance on it?
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I'm now totally confused, some data sheets say 7v and some say 7.6 for both PCC88 and PCC189.
This link shows both 7 and 7.6 volts on the same PCC88 data sheet.
http://frank.yueksel.org/sheets/030/p/PCC88.pdf
One thing everyone seems to agree on is that PCC189 is a Variable mu version of PCC88, and that the heaters are identical.
It's just that the voltage is sometimes 7 and sometimes 7.6, depending on which data sheet you look at for both valves.
For what it's worth, I'm running mine at 7v, and they sound fine.
This link shows both 7 and 7.6 volts on the same PCC88 data sheet.
http://frank.yueksel.org/sheets/030/p/PCC88.pdf
One thing everyone seems to agree on is that PCC189 is a Variable mu version of PCC88, and that the heaters are identical.
It's just that the voltage is sometimes 7 and sometimes 7.6, depending on which data sheet you look at for both valves.
For what it's worth, I'm running mine at 7v, and they sound fine.
How do they sound in comparison to clarity CSA?
I've just ordered a couple, but think I might need a new case to fit them!
I always found the Clarity CAP CSA to sound a little ragged in the top end and that put me off them. the CMR are way better and way more money.
I currently have CMR, MR, and a few other big caps in stock and in truth i dont feel any need at all to remove these Russian PIO's. Listening to Thin Lizzy - Live and Dangerous last night, and i was absolutely convinced it was the best i had heard it sound.
They are impressive. The only thing i don't like is that i had them for months and didn't try them sooner.
I bought 20 of them yesterday, and i might buy more.
they take ages to burn in, so these have been on my cap cooker for about 6 weeks prior to fitting. 6 weeks because i forgot they were on lol
According to this post from Vivant earlier in this thread, your HT is way too high, 125/135 volts too high.
No idea why.
I don't know about better, as I haven't done a proper A-B yet, but I will.
What I'm saying is I don't feel like I am missing out by having the PIO in place.
Going back to PCC88 & PCC189 heater voltages, it seems they were designed to operate on constant current (300ma) as opposed to constant voltage.
Here's a couple of links explaining this.
https://www.diyaudio.com/forums/tubes-valves/18030-pcc88-print.html
PCC88 Heater Voltage Confusion? - XLR8OR - Tubes Asylum
This would also apply to the PCC189, as all available documentation states it is a variable mu version of PCC88 with an identical heater
Here's a couple of links explaining this.
https://www.diyaudio.com/forums/tubes-valves/18030-pcc88-print.html
PCC88 Heater Voltage Confusion? - XLR8OR - Tubes Asylum
This would also apply to the PCC189, as all available documentation states it is a variable mu version of PCC88 with an identical heater
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Did anyone solve this,I to se 7 vs 7,7v in pdf´s.
I changed the zener and now I have voltage ,allthow a little high,280v at C8P.
How do I make it lower the voltage or even make it adjustable??
That's why I posted the links. Because the PCC tubes are designed to work in series in TVs there is no need for them to have a fixed voltage, they need to be run on a fixed current of 300ma. The idea being that all the valve heater voltages would add up near to the local AC supply voltage, and hence not need a heater winding on the power transformer. The voltage is irrelevant.
That said, just out of curiosity I've just measured current on V1 & V3 on my BB, and it appears to be only just over 100ma, but it certainly doesn't seem to affect the working of the unit.
I say that, but not having heard it with the specified 300ma feeding these valves, I don't really know, but I would have imagined that like a "normal" voltage driven valve, higher power would result in better performance (up to a point of course)
Which leads me to a question, would it be beneficial to increase the current through V1 & V3 to 300ma, and how would this be achieved?
Maybe Alan or Oli could comment
ZD2P is for gate protection of the Mosfet filter.
What is your high voltage AC input, around 170 to 175 is ideal. Sounds like you have a lot more.
The HT can be reduced some by fitting a resistor across C5P, try fitting a 1 Megohm and see what you get.