Wanted: Accuphase Transistors!!

[flemo]

Hi Everybody,

I recently had a mishap with my Accuphase E205 amp and as such I need to replace a couple of resistors still to be identified and 4 x transistors.

My main concern is obtaining replacement parts for a 25 year old amplifier.

The attached pic hopefully provides the info for the transistors which I'm chasing.

Any help greatly appreciated, cheers flemo.

 

[jaycee]

that looks like one output transistor, one driver, and two transistors from the VAS. I can bet there is more wrong with it than this.

The driver is a MOSFET, unusual...

Unfortunately pretty much all of these will be obsolete by now. You will be better finding more modern equivalents, but expect to have to adjust the circuit to suit.

 

[stoN_Cold]

The driver is a MOSFET, unusual...

Why not, that is Trade Mark of Accuphase co.

[IMGDEAD]http://i53.tinypic.com/ou5pty.jpg[/IMGDEAD]

Regards zeoN_Rider

 

[anatech]

Hi Flemo,
The only thing that might be more difficult to find may be the 2SK2662. The TO-126 parts can still be found, and are not hard to substitute. The output (2SB863 and compliment) should be even easier to find a substitute for. If any of these are paired, you must find a sub for that as well if you can't get the original part. I don't have the schematic, so I can't be sure on that.

Hi Jaycee,

The driver is a MOSFET, unusual...

Not common, but Revox did something similar with the B-242 in case you wanted to have a look. I suspect this is an attempt to make the load on the Vas more constant with load.

There may be other examples of this design out there, but I can't think of any past Revox off-hand. Anyone else know of any?

-Chris

 

[jaycee]

Hi Flemo,
The only thing that might be more difficult to find may be the 2SK2662. The TO-126 parts can still be found, and are not hard to substitute. The output (2SB863 and compliment) should be even easier to find a substitute for. If any of these are paired, you must find a sub for that as well if you can't get the original part. I don't have the schematic, so I can't be sure on that.

My thoughts were to recommend teh Fairchild devices KSA1220/KSC2690 for the TO-126 devices, and FJA4213/FJA4313 for the outputs. However these are all faster and may cause trouble. Onsemi's NJW21193/4 might be better in this regard.

Have just noticed Onsemi are taking over Sanyo Semiconductor! Let's hope this means some of Sanyo's excellent devices become part of Onsemi's stable and thus more readily available.

Hi Flemo,
Hi Jaycee,

Not common, but Revox did something similar with the B-242 in case you wanted to have a look. I suspect this is an attempt to make the load on the Vas more constant with load.

There may be other examples of this design out there, but I can't think of any past Revox off-hand. Anyone else know of any?

-Chris

I believe Michael Chua tried this in his Ampslab Bi70Mk2 amp. I seem to recall an old Marantz design like this too in my archives, would have to check.

 

[mt490]

A large amount of Sanyo's catalogue is quite readily available through RS components. But they've been discontinuing quite a bit of their stuff.

As for the outputs, based on the minimal information around I would have chosen 2SB817P/2SD1047P, but you're not in luck because these were just discontinued a few months ago by Sanyo.

The FJA devices mentioned above are probably appropriate, as well as the 2STA1962/2STC5242. If you want slow, 2SA2031/2SC5669

 

[flemo]

Hi Flemo,
The only thing that might be more difficult to find may be the 2SK2662. The TO-126 parts can still be found, and are not hard to substitute. The output (2SB863 and compliment) should be even easier to find a substitute for. If any of these are paired, you must find a sub for that as well if you can't get the original part. I don't have the schematic, so I can't be sure on that.

-Chris

Hi Guys,

Thanks for the input. I should have mentioned that somebody else is working on the amp for me and after their examination concluded 4 x transistors and 2 x resistors were unserviceable.

I don't have the technical ability to perform such work or understand some of what you're saying, so please bear with me and dumb it right down!

Chris, the TO-126 parts you mentioned which ones are they in the pic's and where do you think I may be able to obtain them, or what could I substitute them with?

Thanks again for your help and hopefully I'll be able to get this wonderful amp singing again.

Cheers, flemo.

 

[anatech]

Hi flemo,
2SA1360 and 2SC3419 in the picture, but they are not compliments anyhow. Off the top of my head, a 2SC3423 should be the proper pairing for a 2SA1360. Is it possible he hasn't pulled the complimentary device from the unit? The 2SC3419 may be a bias transistor. Anyone have a schematic for this one they can email to me?

Now, I just have to ask. This fellow who is working on this for you, not much experience? Is this person at least specializing in audio, or is most of their work along a different direction? I'm starting to get a familiar feeling about this. There are other factors involved here beyond a replacement of parts thing. Some expertise is required for even mounting the new parts. Notice I didn't say "to screw the new parts down".

Hi jaycee,

Onsemi's NJW21193/4 might be better in this regard.

Yes, I would think so. I think there is still a variant of the MJW0281A and MJW0302A somewhere. Of course, if Digikey or Newark still have these, they would be perfect! A definite upgrade in quality to the original parts.

Have just noticed Onsemi are taking over Sanyo Semiconductor! Let's hope this means some of Sanyo's excellent devices become part of Onsemi's stable and thus more readily available.

Now that is interesting! Where did you hear about this?

Having Sanyo parts may answer my lament that we don't have great signal and low power devices. The newer On Semi outputs are absolutely top quality! Still, I'd rather see the Toshiba signal devices in On Semi's stable. What will probably happen is that On Semi will take the better Sanyo parts and integrate them into the product line while changing the part numbers a bit. This would solve the counterfeiting issues we all face.

-Chris

 

[jaycee]

Now that is interesting! Where did you hear about this?

Having Sanyo parts may answer my lament that we don't have great signal and low power devices. The newer On Semi outputs are absolutely top quality! Still, I'd rather see the Toshiba signal devices in On Semi's stable. What will probably happen is that On Semi will take the better Sanyo parts and integrate them into the product line while changing the part numbers a bit. This would solve the counterfeiting issues we all face.

-Chris

The announcement is on the front page of onsemi.com
My main beef with Onsemi is no good TO-126 sized devices other than BD139/140, MJE340/350, MJE243/253 - all of which are a bit long in the tooth

 

[anatech]

Hi jaycee,
Same beef I have, but they are no worse than any other US manufacturer of semiconductors. I'd like to see some linear small signal BJTs and especially J-FETs as well. Everything they have is long in the tooth - and that's an understatement!

You know what would be truly wonderful for transistors? Pre-grading like the Japanese do.

-Chris

 

[jaycee]

anatech, im sure you would be delighted with Fairchild's stuff... admittedly they are clones of some well known Japanese devices but they are good performers nevertheless. It seems the well known audio JFETs are long since unobtainium unless you want to go with NOS (or risk fakes). I have a couple of the well known Toshiba types from an old Teac amp but am reluctant to use them in a design, simply because I can't replace them if they fail!

 

[flemo]

So, back to my initial inquiry guys, can I source these parts?

If so where?

If not, what generic or similar product could I use?

I'd appreciate non-technical speak as a lot of what was previously mentioned was lost on me!

Cheers, flemo.

 

[anatech]

Hi jaycee,

im sure you would be delighted with Fairchild's stuff...

You're probably right. I have had less experience with them, although I do buy some signal devices from them. J202 and J201 for example. BTW, have you tried these? They are pretty good, but have low IDSS currents. A shift in thinking when you are designing with them. I've also used some of their HV power transistors in regulator designs and I am not unhappy with them. What I have not had a chance to do is play with their parts that might be used in audio power applications. I was so extremely happy with the On-Semi parts that I didn't want to be disappointed.

If you have an idea of some Fairchild parts that you really like, I'd be interested in trying some. Just let me know what to buy. Keep in mind that I don't look for the highest rated parts, as evidenced by my interest in the MJW series of parts. I think they were rated as 150 watt dissipation parts, not the 250 watt devices that attract many others. A PM would be fine if you have the time at some point.

-Chris

 

[anatech]

Hi flemo,

I'd appreciate non-technical speak as a lot of what was previously mentioned was lost on me!

Sorry about that. I didn't expect you to follow that, jaycee and I were talking a bit of shop there.

So, back to my initial inquiry guys, can I source these parts?

Okay, in your neck of the woods I'm not familiar with the market. We do have some members in your country that I know can steer you the right way. Rabbitz is one I would trust.

In general, avoid replacement brands like ECG or NTE. They are unsuitable for audio. You do have to beware of counterfeit and remarked parts. Buying from a safe distribution chain is in your best interests. Authorized distributors for On Semi and Fairchild are good bets. There are also authorized Toshiba, NEC, Sanyo and other brand distributors. In fact, I would expect that you would have an easier time than we do in Canada. My one honest and known Japanese parts supplier closed his doors several years ago. I should have invested a couple thousand dollars in parts before he closed up. Stupid me. Of course, money would have been a problem as well.

I'll see if I can't get Rabbitz' attention on this.

-Chris

 

[rabbitz]

I get most of my semis from WES Components who carry a good range of new and older parts for the Oz electronics repair industry.
WES Components

You may find something at these suppliers but they tend to carry the more modern high turnover items..... Farnell, RS Online, Futurlec.

You need to find the full part number of the semi and for example I think the semi marked C3419 is a 2SC3419 which is in WES's catalogue.

You may find help at Rage Audio in Sydney as he services a lot of the more exotic products and is one of the few knowledgeable techies left. If he can't help you he may be able to give you a direction. He goes by Zaphod Beeblebrox at Stereo Net Australia.
http://www.rageaudio.com.au/index.php?p=1_3

I think Simply Hi Fi are the distributor so may be able to point you to an authorised repair centre.
WELCOME TO SIMPLY HI-FI, THE HOME OF GREAT SOUND AND VISION

With an amp like this you should get it repaired properly by skilled personal rather than to try a DIY approach that could end up in tears and in the end more costly.

 

[flemo]

I get most of my semis from WES Components who carry a good range of new and older parts for the Oz electronics repair industry.
WES Components

You may find something at these suppliers but they tend to carry the more modern high turnover items..... Farnell, RS Online, Futurlec.

You need to find the full part number of the semi and for example I think the semi marked C3419 is a 2SC3419 which is in WES's catalogue.

You may find help at Rage Audio in Sydney as he services a lot of the more exotic products and is one of the few knowledgeable techies left. If he can't help you he may be able to give you a direction. He goes by Zaphod Beeblebrox at Stereo Net Australia.
http://www.rageaudio.com.au/index.php?p=1_3

I think Simply Hi Fi are the distributor so may be able to point you to an authorised repair centre.
WELCOME TO SIMPLY HI-FI, THE HOME OF GREAT SOUND AND VISION

With an amp like this you should get it repaired properly by skilled personal rather than to try a DIY approach that could end up in tears and in the end more costly.

Hi Rabbitz, thanks for the info and I'll make contact with your suggestions.

I'm not fixing the amp myself. A mates uncle who is a retired, highly regarded electrical technician is looking at it for me. He did a diagnosis and handed back the fried bits and suggested I source them. I don't have the ability or knowledge to even consider fixing it myself !

Cheers, flemo.

 

[jitter]

Hi Everybody,

I recently had a mishap with my Accuphase E205 amp and as such I need to replace a couple of resistors still to be identified and 4 x transistors.

My main concern is obtaining replacement parts for a 25 year old amplifier.

The attached pic hopefully provides the info for the transistors which I'm chasing.

Any help greatly appreciated, cheers flemo.

This may not be of much help to you, but by looking at the picture you attached, I'd say your amp was repaired at least once before. The give away is the stylish T-logo on the 2SK2662 as opposed to the simple letter T on the others. It wasn't until the (mid-?)nineties that Toshiba changed the T-logo on their semiconductors.

My Marantz PM80SE from 1993 has Toshiba transistors with the simple T-letter logo. The ones I bought in 1998 had the stylish T-logo, so the switch happened somewhere between 1993 and 1997. That means the 2SK2662 in your picture couldn't be as old as your amp and must be a replacement. Did you have it repaired before?

 

[flemo]

This may not be of much help to you, but by looking at the picture you attached, I'd say your amp was repaired at least once before. The give away is the stylish T-logo on the 2SK2662 as opposed to the simple letter T on the others. It wasn't until the (mid-?)nineties that Toshiba changed the T-logo on their semiconductors.

My Marantz PM80SE from 1993 has Toshiba transistors with the simple T-letter logo. The ones I bought in 1998 had the stylish T-logo, so the switch happened somewhere between 1993 and 1997. That means the 2SK2662 in your picture couldn't be as old as your amp and must be a replacement. Did you have it repaired before?

Hi Jitter, thanks for the info and it may well have been repaired by previous owners. I've had the amp 2 years and purchased it as is. I have no idea what previous work was carried out on it.

Cheers, flemo.