POLL:ROTEL RB-991/990 Owners- Output devices your Amp have? FP/N1016 or 2SA1492/c3856

[dtm1962]

I was just curious who has which output devices in their output stage of your Rotel RB991/990BX/981BX power amps?

FP/FN1016 or

2SA1492/2SC3856

I am just curious why Rotel has used 2 different set of devices for their amps.

From what I gathered if it is not a mistake that the 1016's are darlingtons 8A 70 W (and I assume they operate differently) and the 2SA1492/2SC3856 are standard 15A 130 W devices.

Any comments or let me know what you have in terms of devices!

I am curious about the sound quality diffences and output capabilities if these are not (in my eyes) equivalent.

Thanks in advance,

Dan

 

[ostie01]

Hi, 2SA1492 and 2SC3856 are very commun transistors that can be found in many kinds of amp and power amp.

The FP/N1016 are on stock at: http://pacificsemi.com/index.html
in Canada at around $2.50 each.Good luck

 

[Samuel Jayaraj]

If what you say is true, I am shocked as to how Rotel could use two non-equivalent devices for the same model of amp.

I have extensively modified a friend's RB991 but the sound quality is still pathetic. It was bad to start with and has only worsened in some areas while gaining in others, ie., relatively. The amp that I have worked on has the 2SC and 2SA devices, I think, or I wonder if it was some 2SB and 2SD ones, but certainly not FP or FN.

 

[dtm1962]

Yes it is true.
I bought this on EBay and the output devices look original. I had one FN1016 fail (shorted).

I have decided to replace all the FP/FN1016's with the 2SA1492/2SC3856 which will cost me over $50 but oh well I got the Amp for only $162 USD.

I was surprised to see these crappy overprice darlingtons (misapplied??? in this circuit) in this AMP?????

When I talked to Rotel Parts Center via Email in Canada , it sounded like the FN1016 & the 2SC3856 were equivalent as he would sell either of them to me at the same price.


Sam:

Could you please list me the mods that you performed on the 991 as well.

I am going to mod this until I am happy with sound!

Thanks in advance.

Dan

 

[ostie01]

Hi, $50.00 for outputs 2SA1492 and 2SC3868 seems to be on the high side, they cost only $2.00 each.I never saw a Rotel from this serie working with darlington output, are you sure they are the original parts.

 

[dtm1962]

This AMP has 10 output devices on each side for a total of 20 and the cost that I bought at BD Enterprises (on your recommendation- thank you - I almost bought them at Global Semi in Toronto for $6.00 each!) is about $2.30 X 20 = $46 USD and that equals just over $50 CAD.

I couldn't believe it myself! Rotel Canada Parts wanted to sell them for $12 & $7 each for NPN & PNP respectively!. And they seem to think that the parts are interchangeable as they were going to sell me either of the type Bipolar vs Darlington at the same price!

I have to talk to Rotel Service tech myself tomorrow to see what the heck is going on!

Thanks again for your response!

Dan

 

[ostie01]

Hi, sorry, you're absolutly right, My count was for one channel only.
But I'm pretty sure those are not original. The same amp design could not have darlington and normal transistor output sub.
the 1016 serie are similar to 2sd2438 and 2sb1587

 

[dtm1962]

I feel exactly the same way about this. No way can a design handle both type of devices and still work right!

Thanks again for your help.

Dan

 

[MykhailoM]

Are there any good quality transistors that advisable to use for Rotel RB-991?

to be honest to have a $2 or $3 dollar transistors don't look any good as you probably realised.

Thanks

 

[dtm1962]

Are there any good quality transistors that advisable to use for Rotel RB-991?

to be honest to have a $2 or $3 dollar transistors don't look any good as you probably realised.

Thanks

I would go with the original type as per schematic....