Hi Oscar,Another user asked about a Circlophone stereo version with protection circuit complete on one board, are you interested in that too ?
I did that years ago for a German company, with central star grounding. But without power supply.
Thanks back !
27pf is very ok.Ich denke, ich sollte dem Originalschema ohne Mod folgen, aber ich möchte trotzdem wissen, wie hoch die Toleranz dieses Kondensators ist. Oft verwenden wir dort 10-100pf npo parallel zum Rückkopplungswiderstand.
Jedenfalls habe ich bereits eine Bestellung für 27pf 50v cog mlcc aufgegeben (ich denke, die DC-Spezifikation ist dort irrelevant).
33pF won't make any difference.Dear Mr Elvee do you recommend use of 33-47 pf instead of 27pf for C4? i hve plenty of 47pf COG. Need your advice before i place an order.
Hi Oscar,I had enquiries in Germany about the interchangeability of the relays for my protection circuit.
I then took the trouble to find a relay that is pin compatible.
which is pin compatible. I found the relay with the type designation RW-SS-112D (Goodsky).
1. high switching current up to 15A in small size. (120VAC)
2. sugar-cube relay suitable for various applications.
3. UL, C-UL & TÜV safety standard approved.
4. UL Class F insulation available.
5. Highly adapt to harsh conditions with high
temperature and vibration.
6. halogen free series available.
7. Comply with RoHS and REACH regulations.
8. in accordance with IEC 60335-1 Glow Wire
requirements for home appliances.
Max. On/Off Switching:
Electrical ...............................6 Cycles per minute (this is more than sufficient).
The excitation coil only requires a current of approx. 30mA. For high power applications, such as switching inductive loads, the contact material AgSnO2 is suitable and is also recommended exclusively as a single contact. This relay has a single contact and is therefore ideally suited for switching amplifiers with approx. 150 Watt. The relay RW-SS-112D is pin compatible with the relay HF3FA12. Please note the large D at the end when ordering. The contact resistance is also within the usual range and is only 0.1 Ohm. This is fine!
Now I would like to answer ADITYA's question in post #2210.
Circlophone amplifier stereo on a PCB makes sense, but I would advise against including the power supply on the PCB. I will put the protection circuit on the PCB though. I didn't understand your question about MOSFET (protection circuit?). Sorry
What would make more sense for the circuit board? Left and right arrangement of the heat sink on the PCB ? So then it would be 2 pieces or one common heat sink, aligned as usual at the top in the longitudinal direction of the board ?
Hello Aditya, Ok the solid state relays are a thing of their own, usually they are MOSFET controlled !Hi Oscar,
very informative input on the relays,
I will be comfortable with a board without the power supply as you mentioned
my intention is to use my 215mm x 75mm x 75mm heatsink for stereo. It’s 0.5 k/w for 100mm and is very hefty near about 2kg .
currently I m using My Rev A (LM3886) on it.
Regarding the MOSFET question - I had seen some solid state speaker protection boards and wondered if you had made any or could build one.
Cool I do not intend to go beyond 30watt or in a happy state 50 watts into 8ohms.Hello Aditya, Ok the solid state relays are a thing of their own, usually they are MOSFET controlled !
But now comes the problem, who guarantees that the Mosfet never, I stress never, fails and thus the full operating voltage of the protective circuit reaches the loudspeaker? And the cost-benefit expenditure is simply too great. Let's stay with the mechanical solution. I think that makes more sense, don't you ?
The heat sink you have specified will be sufficient without fan cooling for 2*95 Watt at 4R. More is not possible...
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