572B vs 845 vs 211 SE

[Ryssen]

EML 520 BV-2

Locks like a nice tube,but I think I will have to sell my car to afford them..

Fuling:How do you mean easier to deal with,the 813 is 50w and GM70 is 60w at the filaments.or?

I try single stage already. but if the music was more dynamic, the sound stage not good. So why I choose two stage.

Did you try to drive it with a cathode follower,would be interessting to know what you thougt of that compared to the IT.
I thougt of using a power drive later on,you didn´t try that?

 

[dshortt9]

If you used a C3M single stage to an interstage at 8ma or so it may not have enough current or voltage swing (amplification factor) to push the 845. Also, the plate impedance may have been too high for IT use. Look at Tubezone.com - the powerdrive circuit looks very good.

The low Gm of the 572B makes it not very linear. It also needs to be driven in class A2.

 

[Ryssen]

Where did you hear that one?

I read it at this forum,I did a search,and it was sommething about 812A being better than 811A at low frekvensys.Don´t have a link thow.

It also needs to be driven in class A2.

Yes,thats a nice challenge..

 

[Fuling]

813 is 50w and GM70 is 60w

Yes, but 3A is much easier to rectify and get "clean" than 5A.

 

[Ryssen]

You mean you can use smaller e-lyts with 3A?

 

[dshortt9]

Yes, and 'lytics at 20V are 4x as effective in reducing hum for the same value at 10V.
Ryssen, you caught me before I edited. Lower Mu is better. I was confusing Mu with Gm.

 

[Fuling]

Yes, and things like diode voltage drop and resistive losses becomes less of an issue.

 

[tube-lover]

hi dshortt9,

if I only use C3M triode connect cannot provide enough swing into 845. But I use C3M triode conect with EL504 ( triode connect ) will IT. is it enough?/

any comment for me.

thx


thomas

 

[tube-lover]

hi dshortt9,

if I like to use SRPP to push 520-V3, any comment or circuit will advise??

I hadn't any experiment for this tube.

thx

thomas

 

[dshortt9]

The C3m does not seem to be the best triode, there are others that are better.
http://www.geocities.com/la1zka/hifi/distortion.html
Here are some good circuits for 300b's and 845's
http://www.audiodesignguide.com/myamp.html
If you want to clone the Onganku why not use the 6072 in SRPP to a 5687 SRPP like the original?
The EL504 may not be very good as a triode either. I have not seen it used that way.
I think a good driver would be a 6SN7 SRPP to a 300B through an IT to the output tube.

 

[tube-lover]

hi dshortt9,

many thanks for your advise. But I thought I will continous my choice since although the test of THD of C3M was not the best one.

But in hearing test for our group for C3m triode with EL504 triode cathode follower with 1:1 IT was very good.There may a little different for western & eastern taste.

I had real Ongaku kondo to compare the clone ongaku.

But looks will only for my test purpose. It running too HV & hong Kong people looks not too lke for it.

may thanks for your advise.

I will take the clone ongaku to my friend's real to compare. This is his set up.

thx

thomas

An externally hosted image should be here but it was not working when we last tested it.

 

[pedefede]

since www.imagestation.com
is closed, i can't open your pictures with diagrams. If some of you with diagrams for 520b passes by - please take the time to post new photos.

I'm about to make a 520B-amp myself, and would love to get some inspiration.