Hello Zintolo:
I am currently building another SE 6p15p. I will do some tests with pin 6 connected directly to the cathode verses using a .2uF mkp capacitor. If I understand it correctly this would put pin 6 at the same AC and DC potential as the cathode, with the capacitor it puts it at the AC only potential.
It will take a few weeks to get to that point.
I am currently building another SE 6p15p. I will do some tests with pin 6 connected directly to the cathode verses using a .2uF mkp capacitor. If I understand it correctly this would put pin 6 at the same AC and DC potential as the cathode, with the capacitor it puts it at the AC only potential.
It will take a few weeks to get to that point.
@planet10 Hi Dave, I posted a pic of your datasheet of the Tamradio on Facebook. I got this remark in one of the groups.:
Winding ratio is not 606! Thats just impedance ratio. Winding ratio will be unsquare from 606. Which means it will be something around 25.
I suppose winding ratio is the same as turning ratio.
Winding ratio is not 606! Thats just impedance ratio. Winding ratio will be unsquare from 606. Which means it will be something around 25.
I suppose winding ratio is the same as turning ratio.
Attachments
The important thing is teh reflected impedance, the math is right, the name i use dmay not be. This stuff is right out of the text book i used to figure out what to measure and how to do the math.
dave
dave
Yes, wrong term. I did a zillion of those and that is the first time someone pointed out i was using the right term. Thse images date from over 15 years ago.
Anyone know what b+ I should aim for with the SV83? The datasheet says no more than 200v on the screen. But I know for a fact it can survive that. My b+ was 270 yesterday...got it dialled down to 255. Should it be lower?
Should be fine for triode mode. only time it gets funky is when plate and screen are at different potentials static, and the plate swings too far from the screen during signal.250-180 should work as long as the bias doesn't drift or redplate.
Hello Bas:
The measurement on my RH6p15p are 286v on pin 7(Plate), 195v on pin 9(grid3), 4v on pin 3(cathode). I used a 100v zener diode between B+ (300v) and pin9. The data sheets contradict each other so I went with the suggestion by A. Kitic on his website.
I have not recalculated yet, but I am over driving it at full volume. I suspect it is the bias setting on the 12at7 @ 1.3v as my CD player puts out more than that.
I hope this helps
The measurement on my RH6p15p are 286v on pin 7(Plate), 195v on pin 9(grid3), 4v on pin 3(cathode). I used a 100v zener diode between B+ (300v) and pin9. The data sheets contradict each other so I went with the suggestion by A. Kitic on his website.
I have not recalculated yet, but I am over driving it at full volume. I suspect it is the bias setting on the 12at7 @ 1.3v as my CD player puts out more than that.
I hope this helps
Bas, a real 6P15P-ev can take 330 V on both plate and screen. The parameter to watch is dissipation, especially the screen dissipation - keep it well below 1.5 watt specified as maxs, preferably under 1 watt.
Hello Bas:
I agree with Francois. It is all about current and dissipation.
I agree with Francois. It is all about current and dissipation.
I came to this forum as the Hazen mod has been spoken about here quite recently. Though I have no Deckware amp, I came across the Hazen mod while digging through some information by Mr Deckart.
I have done the Hazen mod in my own single ended el34 amp. It is not a clone but my own design. Though I was skeptic at first and I must say the Hazen mod is incredible. I have done extensive testing with and without the capacitor in place. I agree fully with them this impact is bigger than changing the output transformer haha.
I have tested electrolytic and film caps. What I notice is simply the same topology applies as does to the cathode bypass capacitor. This means low ESR audio grade capacitors. I do not necessarily notice a difference between electrolytic and film caps. The effects are the same, bur the cap merely does some fine tuning in sound for me. I settle for a value of 200uf (Silmic II ) as this is fits in my amp nicely and I prefer the sound.
What I notice in sound is impeccable though. Beware you will need speakers with very good resolution power (ribbon tweeters for example) to notice what is really going on in the very high frequencies otherwise it might give the impression the treble has been slightly cut which is not the case.
The sound stage has resolved very well and for the first time I have heard proper 3D / holography. Sibbilance is gone and liquidity increased. I cannot describe it really. For the first time I really get the feeling the artist is in my room. And no this is not distortion, in fact it is less distortion because I measured it. Also it is way easier to listen to.
I can only imagine what it does to the Deckware clones / amps.
It was the smallest one I had on hand which sounded “good”. I also tried a 0,22uF MKP cap. And a 100uF electrolytic. They did the trick but did not get rid of the harshness in the upper frequencies the same way the Silmic II does. Hence why I refer that the same topology for capacitor choosing applies as when choosing the cathode bypass capacitor. I notice no difference between polarized or non-polarized capacitors other than the tonal differences which are inherent to the caps.
Just want to be sure I understood the position where these caps are used? You mentioned the Hazen mod. Are you using the 200uF Silmic II in the Hazen mod between EL34 suppressor grid and cathode?