F5 Turbo Builders Thread

[Odysseas]

Hi all,
I'm building an f5t v2, and in the process of testing i managed to fry the fairchilds....Now I'm waiting for replacements. Looking to my stuff this morning i found a quad of 2SK1530 2SK201 toshibas. I read somewhere,don't remember where though, that these thingies could replace the fairchilds.

So, just out of curiocity, has anybody tried these?Any major differences in sound?
I'm thinking, since, i'm waiting and have nothing to do, try them. Any thoughts on what i should change on the boards? I've everything set for fairchilds at the moment.

I would appreciate any recommendations/ideas.

[Rush]

Originally Posted by Odysseas

Hi all,
I'm building an f5t v2, and in the process of testing i managed to fry the fairchilds....Now I'm waiting for replacements. Looking to my stuff this morning i found a quad of 2SK1530 2SK201 toshibas. I read somewhere,don't remember where though, that these thingies could replace the fairchilds.

So, just out of curiocity, has anybody tried these?Any major differences in sound?
I'm thinking, since, i'm waiting and have nothing to do, try them. Any thoughts on what i should change on the boards? I've everything set for fairchilds at the moment.

I would appreciate any recommendations/ideas.

Nelson Pass discusses the 2SK1530/2SJ201 in the original F5T article. I used them in one of my original F5 and they sound great.
Later in the F5T thread Nelson mentioned 2SK1529/2SJ200 as having less input capacitance and is a good option as well for the F5T. Neither of these will pass the current of the Fairchild devises. All of these are no longer in production.

Rush

[buzzforb]

THey will work great and will plug directly in with little effect. Just look up their datasheet and try to get an idea of the VGs needed for the bias you want. Before plugging them in, set your pots below that point about 25%-50%. You have tested you FE and all is good. As long as you mount and isolate them correctly, you should be able to listen within the day.

[jacco vermeulen]

Originally Posted by Rush

2SK1529/2SJ200 as having less input capacitance is a good option as well for the F5T, these are no longer in production.

Oh dear, what a shame.

[buzzforb]

I would love to get my hands on some. If only....

[dazed2]

I have the 1530/201 in mine. I tried the Fairchild's as well.
Personally I like the toshibas more than the Fairchild's. Seems more musical.

However as buzz says make sure you turn down the bias pots before turning it on. As they bias a lot lower than the Fairchild's.

[buzzforb]

As well as having slightly lower C, I believe it is a little more linear in nature. No different than caps. Different flavor of ice cream.

[Odysseas]

So, 0,2-0,25V across the 0,5 Ohm resistance I should be ok for burn in,right?

[buzzforb]

Please restate what you mean. You should get about .300-.400mV across the source resistors. It looks like the Vgs should be in the range of 2-2.5V

[Odysseas]

the rating of voltage at 300-400mV across source resistors is for the fairchilds. Having to be more conservative with the toshibas, i'm thinking of 200-250mV across the R source.
I can't find a clear enough datasheet for the toshibas to take a look at graphs.

BTW did you manage to send the package?