How to choose Mosfets for a CRESCENDO ME

[Harold Barrel]

Hi to all
Since there are extremely experienced people on this forum and I know nothing about Mosfet matching, I'd really appreciate a hint
I'm building a Crescendo Millennium Edition (dual mono version) from the Elektor Magazine article and I'm stuck on the choice of the two pairs of 2SK1530/2SJ201 Mosfets. Apart from the fact that they are not easy to find any more (and I live in Europe) I don't understand what is mosfet-matching about. There's no reference about matching on the Elektor article
So far I have found the following sources to buy them:

1. This Forum
User "NicMac" is selling these Mosfets on the forum from this topic:

http://www.diyaudio.com/forums/swap...s-matched-2sk1530-2sj201-f5-f5-turbo-f5x.html

And this is the list of his available Mosfets:

https://docs.google.com/spreadsheet...BBqLqnYq03e5_z798RoW0/edit?pref=2&pli=1#gid=0

Looking at the list, I really don't know which one I should choose...


2. Tech DIY Company Store
http://www.tech-diy.com/Store/LatFets.htm

They sell a pair of these mosfets for 12$ and a matched pair for 40$, a significant difference in the price!!

3. AmpsLab
2SK1530 2SJ201 Toshiba Mosfets - Buy Online @ AmpsLab

40$ for two pairs. No specification about matching.



Many thanks in advance

 

[thimios]

Crescendo me, is a 1 pair output amplifier ,so you can use unmatched mosfets

 

[nigelwright7557]

A cheap readily available pair would be irfp240/irfp9240

 

[Harold Barrel]

Crescendo me, is a 1 pair output amplifier ,so you can use unmatched mosfets

Thank you thimios
So you are saying that I could choose any two pairs of the ones sold by NicMac on this forum and it won't make any trouble in the amp?

cheap readily available pair would be irfp240/irfp9240

This sounds also interesting!
You mean that this pair would be a perfect equivalent to the 2SK1530/2SJ201 Toshiba pair? No MODs required in the amp design and/or wattage power difference?

 

[Cal Weldon]

Harold,
You are under moderation for the first few posts like all new members are. When you edit a post, it goes back into the queue to be re-moderated.
That's "where the hell" it went

 

[nigelwright7557]

This sounds also interesting!
You mean that this pair would be a perfect equivalent to the 2SK1530/2SJ201 Toshiba pair? No MODs required in the amp design and/or wattage power difference?

Should work fine.
I have designed and built numerous amps with these mosfets.

 

[Harold Barrel]

So, thanks for your responses so far.
I have decided to build the amp with the original mosfets and not with the IRFP240/IRFP9240 because I've found a Chinese seller who sells 2SK537, 2SK1530 and 2SJ201 mosfets at a very good price
He says that all the transistor are new and original from Toshiba (I've asked) but there's no matching.

Here are the ebay links:
5pcs 2SK537 Encapsulation to 220 Transistor MOSFET N Channel 900V | eBay
2SJ201 Encapsulation to 3PL | eBay
1pcs 2SK1530 Encapsulation to 3PL N Channel mos Type High Power Amplifier | eBay

If someone could please confirm that the absence of matching won't make any difference in my stereofonic (dual-mono) version of the Crescendo ME, I'll buy them

Otherwise, there are still same matched pairs from NicMac (https://docs.google.com/spreadsheet...BBqLqnYq03e5_z798RoW0/edit?pref=2&pli=1#gid=0) but they are more expensive.


Thanks in advance

 

[Ian Finch]

There is nothing to match if you only have a single pair of mosfets, transistors or whatever. This has already been advised by thimios.

If there were 2 or more Mosfet pairs in each channel, there could be some benefit to current sharing by matching the N types and also matching the P types separately, because N and P type Mosfets will never match as complementary pairs. Consequently, if you only have 1 pair in each channel, don't bother trying to do what is impossible.

 

[Project16]

@Harold Barrel.
I can not confirm whether it is the original and if they are matched but here's another source mosfets.
Semiconductor: 2SJ201KIT (2SJ 201 KIT) - TRANSITOR KIT 2SJ201-Y (F) AND... - US$ Site

And another with matched pair.
Tech DIY Company Store

 

[Harold Barrel]

There is nothing to match if you only have a single pair of mosfets, transistors or whatever. This has already been advised by thimios.

Ian Please, don't be upset
I haven't ignored thimios' advice; I just wanted to be sure - this will be my first audio amplifier and I'd like it to sound good!
So, thanks for your explanation Now it's clear.


Thank you too, Project16
I've had found that sites also. The Irish one is somewhat expensive...
I think I will go for the Transistors sold from the Chinese store. He claims that all the items are original, do you think I can trust him? Here are the images:

 

[Ian Finch]

Beware - Ebay sources, even those reputed to be good, like UTsource, will supply different parts to those pictured. I have ordered Sanken power transistors several times and once received only half the order as genuine parts. Other supplies were either unbranded or had obscure Chinese brands and none were anything like the OEM product. If you believe that you can have both cheap and genuine, dream on. Test the marks, see if they wipe off with solvent or are badly laser etched. Counterfeit Transistors

Think carefully about what cheap means for NOS, obsolete parts. It means fakes, remarked substitutes, forgeries, copies and more fakes. If you want best quality, genuine obsolete parts, you are looking to the wrong source.

 

[Harold Barrel]

Counterfeit Transistors

Most illuminating, Ian. Thank you. Ok, no Ebay!
I thing that this thread will be very useful to people trying to put together this amp.

So now I have two options: to buy the Mosfets from this forum (which is now the only source that I consider reliable) or to find an equivalent.

Nigelwright7557 suggested to use the IRF240/IRF9240 pair instead of the original 2SK1530/2SJ201. I've tried to compare the datasheets and yes, I don't notice any major difference, also the dissipated power is the same (150W). What would think about this solution, Ian?

The Toshiba 2SK537, needed for the pre-stage, is even more difficult to find. I've found the IRFIBF20G to be an equivalent but even this one is rare. I'm open to suggestions

Thank you guys!

 

[nigelwright7557]

I have a couple of Fane Crescendo's in these folded horns.

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

 

[Ian Finch]

Nigelwright7557 suggested to use the IRF240/IRF9240 pair instead of the original 2SK1530/2SJ201. I've tried to compare the datasheets and yes, I don't notice any major difference, also the dissipated power is the same (150W). What would think about this solution, Ian?

Nigel is correct. The IRFP240/9240 pair are one of the few "complementary" Hexfet power transistors suitable for audio and still in production. You can buy product manufactured by IR or Vishay.

The original Crescendo series designs used lateral mosfets which are still available from Renesas, Exicon and Magnatech so there is still good support from manufacturers for that type of Mosfet.

I haven't sourced 2SK537 but I recall there are other threads here discussing the topic: http://www.diyaudio.com/forums/solid-state/194826-another-crescendo-me-problem.html
Dönberg (an Irish parts seller) advises that 2SK1643 is a replacement.

 

[thimios]

Many years ago,Elektor recommendation is 2sk1338 instead of 2sk 537.
I used this in my crescendo.

 

[Harold Barrel]

Sorry for my late response, I had been away for a week!
It's nice to find your suggestions here.

So, according to your advices and to the thread mentioned by Ian, this could be a small list of replacements/equivalents:

2SK1530/2SJ201 --> IRFP240/IRFP9240
2SK537 --> 2SK1643 or 2SK1338 or 2SK2733
OP77GP --> OP177GPZ

I've considered also the OPamp because I couldn't find it too.
I have found a german ebay seller who has in stock the IRFP240/IRFP9240 pair, 2SK2733 and OP177GPZ. He's got also the MPC71 resistors and the relays both for the soft start and the protection board.

Now, IRFP240/IRFP9240 are still in production. Do you think I can trust Germany more than China?

IRFP240 Vishay SILICONIX MOSFET Transistor 200V 20A 150W 0 18R TO247AC 850316 | eBay
IRFP9240 Vishay SILICONIX MOSFET Transistor 200V 12A 150W 0 5R TO247AC 850315 | eBay
Toshiba MOSFET 2SK2733 Japan Transistor High Speed High Current Switching 852085 | eBay
OP177GPZ Analog Devices Op Amplifier 0 6MHz 0 3V ?S Ultraprecision OpAmp 856153 | eBay

 

[katiyar]

Will Hexfet mosfet like IRF240 & IRF9240 will be a direct substitute to Lateral mosfet in Cresendo Amplifier circuit. I have two PCB of Cresendo amplifier but could not finish due to non availability of Hitachi 2SK135 & 2SJ50 Lateral mosfet in India. I think Lateral Mosfet has a lower Gate source threshold voltage as compared to Hexfet Mosfet. Due to this I think the original circuit will need a change in drive circuit. Can some one who has done modification guide me regarding the change.

 

[rsavas]

It is the gate bias generator voltage range and thermal compensation that needs to be designed for each different type of device technology. Lateral types do not need thermal feedback

 

[Ian Finch]

You can still buy Exicon TO3 replacement types for 2SK50/J135 from Profusion PLC in the UK. For the closest equivalent types, just compare datasheets. Definitely not cheap though.
Lateral MOSFETs (Buy Online) | Profusion

 

[NMOS]

Will Hexfet mosfet like IRF240 & IRF9240 will be a direct substitute to Lateral mosfet in Cresendo Amplifier circuit. I have two PCB of Cresendo amplifier but could not finish due to non availability of Hitachi 2SK135 & 2SJ50 Lateral mosfet in India. I think Lateral Mosfet has a lower Gate source threshold voltage as compared to Hexfet Mosfet. Due to this I think the original circuit will need a change in drive circuit. Can some one who has done modification guide me regarding the change.

Be aware this old circuits

schematic need to be redesign, amp will not work stable and oscillate

any there is no group wil help you with problems

it was my first amp 20 year ago


For same material count you can build DIY class D

google Indonesian Class D next generation FB group