Here is a version with MJL4281 devices in TO-264 and also NJW3281 in TO-3P🙂. Also drivers can also be MJE15XX.
regards
Prasi
regards
Prasi
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a member asked me if i can supply pcb for this amplifier as per post # 261.
so if there is interest from atleast 3-4 members + with permission from Mr. Mile, i can get pcbs from board house and supply pcbs to those interested members.
regards
Prasi
so if there is interest from atleast 3-4 members + with permission from Mr. Mile, i can get pcbs from board house and supply pcbs to those interested members.
regards
Prasi
Yes prasi if your board supplier is local I would be interested in a couple. Since money transfer would be international, best if you make an e-bay listing and link it from here. Bare boards, I have semiconductors already.
Bruce, that op amp is no longer available. RCA is a naked name like Sunbeam, the fab factory was torn down decades ago. Not entirely off topic, it does have single supply. The AX6 design should be able to drive several pairs of output transistors off board if you put heat sinks on the driver transistors. My Ax6 has off board output transistors, I did put an inductor in the return from the temperature sense over there on the heat sink to prevent oscillation from occurring. Also space the base drive wires away from the temp sense wires.
Bruce, that op amp is no longer available. RCA is a naked name like Sunbeam, the fab factory was torn down decades ago. Not entirely off topic, it does have single supply. The AX6 design should be able to drive several pairs of output transistors off board if you put heat sinks on the driver transistors. My Ax6 has off board output transistors, I did put an inductor in the return from the temperature sense over there on the heat sink to prevent oscillation from occurring. Also space the base drive wires away from the temp sense wires.
I love the sound of the single supply amps too, far better sounding than today's mass made stuff class d ect. I've got PV1200 box with a working transformer the original boards were not worth repairing so I'm going to pop in 2 AX6 modules and will double up on the output stage . I have also attached a photo of one of my favorite single supply modules the AL125 from Autona. In the 80's virtually every mobile disco in SA used these, and I still love their sound, together a pair of Fane 12 speakers, 2 x BSR turntables and a pile of old vinyl what could be better
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You're right. The amp topology otoh has all the characteristics of a single-supply circuit.
Perhaps the output cap isn't drawn on the schem? Or the schem is drawn with the intent to "confuse".
Perhaps the output cap isn't drawn on the schem? Or the schem is drawn with the intent to "confuse".
Hello Indianajo,
Thanks for your interest.
regarding PCBs, I was thinking more on the lines of getting 10nos. of PCBs with nice double sided , red masked from China. Local manufacturing for small qtys is costly as they charge development charges. Its only cheap if we go for higher qty.
ebay is not not possible for me, as I am only going to produce 10 nos and moreover, to register as an ebay seller in India, one needs to have a commercial tax number (GST no.) from Govt. of India..... Complicated!!😱
I have been using paypal for accepting and paying money without any issues till now and made many transactions with no issues whatsoever.
If the demand goes to more than 30-40 nos, I can get single sided PCBs quickly manufactured locally.
regards
Prasi
P.S. the 'list'
1. Prasi 2 nos
2. Member thro PM 2 nos.
3. Indianajo 2 nos.
Mouser still offers this CA3130, now made by Renesas/Intersil, both in DIP-8 and SOIC cases.
Quite a strange design, though, with that thermal compensation by controlling the predriver's current.
It is a dual rail amplifier, but without the ltp front end. It doesn't need an output capacitor. And yes, it is drawn somewhat confusing.
Best regards!
It's drawn as it is a dual-rail but I fail to see how exactly could the bd240 bottom output pair driver get the "negative" swing required at its base for dual rail operation - and this with all the bootstrapping going on there (imho it can get only a diode-drop + VBE mult drop below the bc441 collector). Most likely a sim would clear things up but ... not at this time.
In the 1980's I had a similar setup with BSR decks, vinyl and a 225WRMS Maplin amp. Worked very well for a good few years.
I havent made a bom yet, if I end up ordering the boards, then I will prepare one and share here. I was planning to use whatever available in my parts bin otherwise.
regards
Prasi
P.S. here is the final ver. with some additional options like zobel, regular 2 legged diodes, cap options, etc
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1. Prasi 2 nos
2. Member thro PM 2 nos.
3. Bix 2 nos.
Once the total reaches 10nos., I will order the boards
2. Member thro PM 2 nos.
3. Bix 2 nos.
Once the total reaches 10nos., I will order the boards
The Autona AL125 was a single supply of 80v. If you replaced the 2N3055 with MJ15003 you increase the voltage to 90v. The speaker coupling capacitor was not shown in the circuit as unlike the AX6 it is not mounted on the board. Nigel I did build the 225watt Maplin circuit and it worked well but I just could not get the bias current to adjust, but personally I still prefer the AL125 sound
Just having had a close look at the circiutry in #1 again: Shouldn't the voltage divider provide a potential of about half the supply voltage for the first transistor's base?
Best regards!
Best regards!
This confirms my observations.
That amp schematic is surely drawn with intent "to confuse", haha.