I tried the 12BH7 is several designs inlcuding the White follower and found it to be rather poor. Then I discovered the ECC99 after reading Pete Millett's headphone amp article. The ECC99 is definitely are far better tube for headphones applications.
Cheers
Ian
The ECC99 seems to be better than the Russian 6N6P in spite of the fact that the Russian tube has lower plate impedance and higher Gm, as I recall anyway. I tried spice models of both in my circuit and the ECC99 performed better. I'm just concerned that there is only one manufacturer for that tube.
Hi,
AFAIK the 6N6P (not sure if there's a Chinese version) is no longer in production whereas the ECC99 is.
My main concern with the JJ tubes is the general quality, they tended to be all over the place after a while.
Not sure if it's still the case today but it might worthwhile to check it out.
Ciao,
AFAIK the 6N6P (not sure if there's a Chinese version) is no longer in production whereas the ECC99 is.
My main concern with the JJ tubes is the general quality, they tended to be all over the place after a while.
Not sure if it's still the case today but it might worthwhile to check it out.
Ciao,
Whatever the simulations might say, in practice there is little measureable difference between the two tubes. Perhaps its time to turn off the simulator and turn on the soldering iron.
Cheers
Ian
If you'd check my FB page, you'd see that I have been soldering... I do actually make stuff in real life.
Even so, since all of the parts I need have to be obtained via mail order, it takes a long time to get some things. For example, the transformers have a lead time of 4 weeks. In addition, I do not have a ton of money to throw at these projects, and I refuse to make junky looking crap. The custom circuit boards have a typical lead time of 14 business days and they are expensive! And, once again, I don't want crap. I want professional results.
Just yesterday I received my 1.5" Greenlee chassis punch. I don't know if you're aware of this, but these things are expensive! I needed it for the little electric fan that's going into my project. Then, after punching the hole, and drilling the holes for the screws to mount the fan, I realized I didn't have the proper length screws on hand. So, off to the internet to mail order them, but of course, I don't want any old crappy looking screws, I want stainless steel socket button head screws, which are located in Texas, which take 3-7 days to get here after the ship.... It took me at least an hour just to make the holes in the chassis for the fan (that's one 1.5" hole and 4 precisely located 1/8" holes for the screws). Yes, it turned out very well.
So, the upshot is that I have plenty of time to fiddle with the simulator while I wait for parts. I also use the simulator to just point me in the right direction, not to give me precise results that I expect to see in real life, which brings up another issue: measuring this stuff in real life. How much money and gear do I need to really measure how good the things I make are performing? It's a lot, actually. That means more money and time waiting on mail order delivery.
That's why I play with the simulator a lot.
That's fine. Perhaps, when contributing to threads such as this one, it would be useful if you pointed out that the circuits you are posting are only simulations and not ones you have actually built so as not to mislead people into thinking that the performance you quote for them has actually been measured on real hardware.
Cheers
Ian
Hi,
Beside the max. grid leak resistor value there's also max Vf/k that's totally missing.
If anyone would know these that would be grand.
Absolutely.
But prior to the appearance of the ECC99 choices were rather limited if you wanted to use something "off the shelf" without running into premature obsolescence problems.
IME for similar duties one could use a 6(/12)CG7 instead of the 12BH7A with generally better results.
Some years ago I also posted a design of mine using an SRPP stage coupled into a twisted WCF/SRPP stage using ECC99s that could be used as both a line pre and a headphone amp (the latter use limited to a range of headphone but still).
I'll see if I can dig it up.
EDIT: Here it is:
http://www.diyaudio.com/forums/tubes-valves/40425-ecc99-line-preamp.html
Note that it is not yet optimized so take it for what it was. A quick draw burning the midnight oil.
@Dirk: I checked the measurements you took for the buffer stage against my data taken decades ago and they are spot on. Well done Tina and Dirk.
Ciao,
Beside the max. grid leak resistor value there's also max Vf/k that's totally missing.
If anyone would know these that would be grand.
Absolutely.
But prior to the appearance of the ECC99 choices were rather limited if you wanted to use something "off the shelf" without running into premature obsolescence problems.
IME for similar duties one could use a 6(/12)CG7 instead of the 12BH7A with generally better results.
Some years ago I also posted a design of mine using an SRPP stage coupled into a twisted WCF/SRPP stage using ECC99s that could be used as both a line pre and a headphone amp (the latter use limited to a range of headphone but still).
I'll see if I can dig it up.
EDIT: Here it is:
http://www.diyaudio.com/forums/tubes-valves/40425-ecc99-line-preamp.html
Note that it is not yet optimized so take it for what it was. A quick draw burning the midnight oil.
@Dirk: I checked the measurements you took for the buffer stage against my data taken decades ago and they are spot on. Well done Tina and Dirk.
Ciao,
Last edited:
I think I have a new champion headphone amp. It only uses 2 tubes, but it needs a special transformer. It simulates at 0.003% THD @ 20 Hz @ 1 Vrms into 50 ohms. THD @ 1 kHz is about the same.
https://plus.google.com/u/0/b/111642951711044611308/
https://plus.google.com/u/0/b/111642951711044611308/
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.