Sick pioneer SA6200

[pre65]

Have you made a start on the EL34 amp yet ?

[colin.hepburn]

Have you made a start on the EL34 amp yet ?

Yep must get on with the EL34 just need to get PSU Caps and EL34 Cathode Resisters I prefer to have all the parts first before starting but getting there now just got some bills in the way

[al newall]

What cathode resistors do you need Colin?
Might have something suitable.

[colin.hepburn]

What cathode resistors do you need Colin?
Might have something suitable.

Hi AL
Options are2x 880R 5/10 watt or 1k2 /3k3 best to go with the 2x680R i think
See http://www.audio-talk.co.uk/phpBB2/view ... 6163#56163

[Mike H]

Hi All
Anyone know of a good website for transistor Cross referencing i.e. Comp to and equivalents I a m trying to find good low noise up to date new equivalents for the following

2sa764/2sa726 to92 ECB/BCE 30v 50mA 0.2w 250hfe 120MHz
2sa820 / 2sc1318 to-92 ECB 60v 0.5a 0.625w 85-340hfe 200 MHz
2SA720 PNP TO92 ECB 60V 500mA 200MHz
2sa489 / 2sc789 to-220 BCE 60v 4a 30w 40-240hfe 3 MHz

I would say, just look for types with the specs you want, Volts, current, power, Hfe, case style. Not too sure you'll notice any difference compared with the ones the amps's already got. I haven't yet. As I remember


 

[colin.hepburn]

Hi All
Anyone know of a good website for transistor Cross referencing i.e. Comp to and equivalents I a m trying to find good low noise up to date new equivalents for the following

2sa764/2sa726 to92 ECB/BCE 30v 50mA 0.2w 250hfe 120MHz
2sa820 / 2sc1318 to-92 ECB 60v 0.5a 0.625w 85-340hfe 200 MHz
2SA720 PNP TO92 ECB 60V 500mA 200MHz
2sa489 / 2sc789 to-220 BCE 60v 4a 30w 40-240hfe 3 MHz

I would say, just look for types with the specs you want, Volts, current, power, Hfe, case style. Not too sure you'll notice any difference compared with the ones the amps's already got. I haven't yet. As I remember

Thank mike
Yep I was just looking at what's about for low noise UK Transistors like the BC BD types as it is the power amp sounds very good but the preamp and phono stage throws a hissy fit maybe in part due to old 5 % drifting carbon resistors a 2sc789 will cost £9.99 each i wont be paying that for a 40 plus year old transistor

[Mike H]

Oh does it? Beg your pardon then.

OK well could cruise RS or Rapid for matches, you would hope anything modern would be better made. Doing something about the resistors sounds like a good idea as well.



 

[al newall]

I should have a pair of 820R 50w resistors.
I came across one of them last night, if the other turns up would they be any use?

[Mike H]

2sa764/2sa726 to92 ECB/BCE 30v 50mA 0.2w 250hfe 120MHz
2sa820 / 2sc1318 to-92 ECB 60v 0.5a 0.625w 85-340hfe 200 MHz
2SA720 PNP TO92 ECB 60V 500mA 200MHz
2sa489 / 2sc789 to-220 BCE 60v 4a 30w 40-240hfe 3 MHz

I was starting to look into this last night but ran out of time.

Only thing is which are NPN and which are PNP?

Or, could you post a scan of the circuit that uses them



 

[colin.hepburn]

2sa764/2sa726 to92 ECB/BCE 30v 50mA 0.2w 250hfe 120MHz
2sa820 / 2sc1318 to-92 ECB 60v 0.5a 0.625w 85-340hfe 200 MHz
2SA720 PNP TO92 ECB 60V 500mA 200MHz
2sa489 / 2sc789 to-220 BCE 60v 4a 30w 40-240hfe 3 MHz

I was starting to look into this last night but ran out of time.

Only thing is which are NPN and which are PNP?

Or, could you post a scan of the circuit that uses them

Yep
If we take the 2sc789 -220 BCE 60v 4a 30w 40-240hfe 3 MHz an equivalent can be a TIP 41C NPN TO220 100V 6A 65W but the bit I don't understand is the hfe is different and the MHZ is also different then they have to be matched pairs a night mare

[Mike H]

Oh I see "equalizer" means "phono" lol

The last two I got already

You want to change them all?

Not sure matched pairs are absolutley necessary, or be noticeable, can't say I've noticed too many differences buying a batch

The Ft (terminal frequency, MHz [at which gain is reduced to X1 - I think]) can be a pain in the arse actually if it's too high.

So it's mostly down to working Volts and Hfe. I'll look into it later, most probs I'll look at BC numbers for the low power ones


BTW that phono circuit is quite well designed, that's a classic way of using DC feedback to get the bias for Q1 and keep the whole thing in the right area for DC Voltages.



 

[colin.hepburn]

Hi Mike
Thanks for the help
The following ones were suggested to me what's you views


For all the TO92
BC639 PNP TO92 EBC 80V 1A 1W 100MHz
BC640 NPN TO92 ECB 80V 1A 1W 100MHz

For Drive TO220
MJE15030 NPN TO220 150V 8A 50W Hi Fi Driver
MJE1529 PNP TO220 150V 8A 50W Hi Fi Driver
Yep the phono stage sounds good but a lot of hiss


IF you want a copy of the full serves Manual I uploaded it to hifi engine


http://www.hifiengine.com/manuals/pioneer/sa-6200.shtml

[Mike H]

Oh I see, well BC640 has low Hfe actually so not too sure about that.

Back shortly....



 

[Mike H]

OK so where it is written:


2SC1344/2SC1312 (npn)

I would say BC549 (Rapid 81-0069)

That's all the pre-amplifier ones.


Power Amp:
2SA763/2SA726 (pnp) ~ BC558 (Rapid 81-0184)

2SC1318 (npn) ~ BC639 (Rapid 81-0080)

2SA720 (pnp) ~ BC640 (Rapid 81-0082)


2SA489 ~ MJE2955T (pnp TO220)

2SC789 ~ MJE3055T (npn TO220)


^ http://uk.rs-online.com/web/search/sear ... breadCrumb






 

[colin.hepburn]

OK so where it is written:


2SC1344/2SC1312 (npn)

I would say BC549 (Rapid 81-0069)

That's all the pre-amplifier ones.


Power Amp:
2SA763/2SA726 (pnp) ~ BC558 (Rapid 81-0184)

2SC1318 (npn) ~ BC639 (Rapid 81-0080)

2SA720 (pnp) ~ BC640 (Rapid 81-0082)


2SA489 ~ MJE2955T (pnp TO220)

2SC789 ~ MJE3055T (npn TO220)


^ http://uk.rs-online.com/web/search/sear ... breadCrumb

Cheers Mike
That will do nicely should get all for less that the price of one 2SC789