Complementary Questions

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At the OP stage; have you guys tried NJW21193/4 as triple complements - ie triple EF or close? It's not straightforward comparing Hfe at 8W with the 3W spec of the Toshiba clones 3281/1302 and 5200/1493, but I assume the 21193/4 are lower with lower Ft too, which might be safer in that application.

OK, price is higher and availability is not so good (do any major distributors hold stock?). Stability is a greater issue though. Os, you work with plenty of triples - any thoughts?

I built a triple , not worth it... with my standard mje15032/33 - njw0281/0302 OPS's I get easily 2k hfe in a standard EF2 setup. loads the voltage stage <1ma even at 4R. Thermal and electrical stability with the EF2 is SO much better. price is another factor , the above mentioned OPS is only 8 X $1.40 =$11.20(NJW's) vs 6 X $4.00 = $24 (21193/4) for the same 200w/8R OPS. The slightly smaller NJW's also have 3 X the Hfe (100+).
OS
 
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Thanks for your words on triples guys. I know they are hard to implement with our modern, high gain parts. All the standard advice I read says to use old or low gain, like Hfe 20 at the design max. output current. Then try to find a driver with low gain too. Add good linearity requirements and I guess there is really not much economically available.

I get the point about not being worth it Os. 100 Hfe is just not gonna help - Still, I just have to try to DIY the wide crossover region thing....like Cyrus amps for example.
Now they did use some unlikely output complements, even a quasi pair to keep overall gain low. The sound of a couple of their models I have owned is good to my ears but I have not seen distortion spectra. Perhaps Anatech, being a service agent, has checked this out and may have a comment.

Hi Sajti. The no (I guess) GNF triple would be good to hear about..and just to hear! Have you posted something about this design in another thread?
 
Hi,

my project is hybrid amplifier. Tube vas, and triple darlington output stage, fully balanced. Expected output power is 200W/8ohms, and can handle the load down to 2ohms.
When I started to plan this amplifier, I have made this topic. But after some listening, I have changed to NJW0xxx, and reduce the number of the output devices to 2x6pairs, and use better drivers.

Sajti
 
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Thanks Sajti, Now that is a project. I hope it has come together well for you. I think Bigun would also be very interested in your tube input/no GNF approach and possibilities to build it with just a basic OP stage.

A Question about low-gain audio output complements: They seem pretty rare unless you look at old, low lineariy types. Do you know of any types that would rate 50W/ eight ohm or more in class AB?

To start, I have found Ebay clones of the QUAD 405 using SANYO 2SD1047 --quasi- complementary. The PNP complement is 2SB817.
CYRUS 3 also uses these TO3P-h or TO247 types. They must be OK in triple since no base stoppers are used.

Other sugestions?
 
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