F6 Amplifier

[buzzforb]

Enjoying Bad Plus, "These are the Vistas". I think you might even like this one, ZM.

 

[elfischiso]

Hi!
ZM said the 2SK170 and 2SJ74 should have an Idss of 8mA.
I have two pair of the GR-types here, which have an Idss of 4,70/4,80mA. Will they work in this circuit?
What do I have to change in the circuit to make it work?
What are the disadvantages when using GR-types? Do you recommend to get some BL types?

I'm sorry, if it is a stupid question, but i'm quite new to electronic circuits..

Thanks a lot!
Stefan

 

[Zen Mod]

just toss them in and make entire shebang

when/if you can find pair of BL matched ones , replace them

generally - with higher Idss group , xconductance is guaranteed to be higher , so output impedance of buffer is lower , which can't be bad thing

 

[elfischiso]

Thanks Zen Mod!
As I'm still waiting for some other parts, i will try to get some BL types...


Stefan

 

[Zen Mod]

at last !!

http://firstwatt.com/pdf/art_f6.pdf

 

[buzzforb]

Ring one up for the good guys

 

[cochleus]

yep... He rang my bell...again...
Amazing that he is going to so much work!

 

[Mr. dB]

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

 

[zany]

Naughty and greedy boy ZM...

 

[generg]

o-k. two channels are running with two Jensens ( I still have to determine the polarities with the ISKRA)......

.....the low level clarity ist very good, I think this amp excels in clarity and articulation. With two channels running, it is easier to see the characteristic of the F6.
For me it is not an amp that increases anything like stage, colors and so on, may be it sounds a bit dry and anti alcoholic ........ but hear yourself, it is for me a new category of sound First Watt amps produce!

 

[buzzforb]

I felt like it did a great job of presenting the different instruments in approp space in the recording. If you were listening to a live album, you could really pick up on the venue. Iam using box speakers and dont know the sound of OB.

 

[generg]

Yes, I can agree buzzforb, that is a quality I can feel too.

 

[Zen Mod]

naah

just another Papamp

you greedy boyz will anyway praise next one as best thing after bread

 

[generg]

No I did not do that, this amp sounds not like F3, M2 and J2 is sounds like F6......

 

[Zen Mod]

I just couldn't resist ...... true or not , it just sounds so good and nasty

 

[buzzforb]

True. They all have a certain character. That is what is amazing to me. I have heard 5 different amps on the same speakers and they are all different. I got to pick one eventually. I was hoping for SiT. but it doesnt look like that is happening now that SS went belly up. I think that leaves one of current SS variations. 4 to choose from, if you dont go SUSY. SS SOX might be interesting for HE crowd. WOnder if there is a way to add FE symmetry to F6.

 

[Zen Mod]

nothing easier ......

just use same tricks from BA3 and BA3 balanced

Pa is lecturing us all the time , but we are lazy bums , most of the time

 

[lhquam]

Does anyone have a photo of the Thd-vs-Freq slide that Nelson showed at BAF? I have no idea what that looks like when tuned to the master's ear.

 

[labjr]

I was hoping for SiT. but it doesnt look like that is happening now that SS went belly up.

Semisouth isn't the only semiconductor company. Most trends seem to be industry wide. Other companies are making SiC FETs etc. Also the technology used in Semisouth parts will probably be sold off to someone else.

 

[Zen Mod]

Do it, it is one of the easiest PTP I made, only thing is to check twice the polarity of the windings to be correct.

@ ZM ISKRA adventure continues tomorrow, my wife has a cold and I have to do the household and some more....

moi hope that Frau is better , by now

anyway , lookielookie .......

red dots on photo are positive end of windungs