PonyTail

In a Power Amplifier, it is not uncommon to have +/-50/70/90V power supply rails, But we are talking pre-amplifiers here which would typically operate from +/- 15 to +/-24V rails and rarely need to output more than 3 volts.

Why 5W ? As a 4.7K 0.5W resistor will handle 48V, and no pre-amplifier will put out that sort of voltage.

I recently purchased an A3148 HDMI Transmitter over IP and two A3149 Receivers. All are PoE equiped and also included plug-packs if PoE is not available, from Altronics. Here is a brief overview: "Converts a HDMI signal into a H.264 encoded stream (maximum 1080p @ 60Hz) and sends it over Cat5e/6 cable using internet protocol (IP) over a distance of 120 metres. The advantage of this method is a reduced network load without sacrificing signal quality. It also allows for data to be streamed over Wi-Fi. These transmitters and receivers are very flexible, allowing for various system configurations including one to one, one to many, many to one and many to many modes. Up to 64 transmitters may be used and a total maximum of 256 transmitters & receivers per system. Each device in the system can be individually addressed with support for IGMP and DHCP automatic addressing. Importantly, PoE (802.3af) has also been included, allowing for the transmitter and receiver to be powered directly from a PoE equipped switch, eliminating the need for individual plugpacks. It also allows an infra-red signal path back to the source equipment for remote control at the receiver location. These units are ideally suited for multi source, multi screen environments such as clubs, pubs, convention centres, venues etc. HDCP compliant. " Don't know about the 120m claimed range as I thought Cat 6 was limited to 100m. I am using these to send my CCTV output to a rear room and a workshop. As the source is derived from H.264 cameras and an XVR, there is a slight quality loss which may not be there if fed from another source.

100% agree with what Art Vanderlay said, with one addition to the original question: If you look at the biasing arrangement it is between both output transistor stages, so it affects both equally.

Hi, I have a large stock of KSA1220AYS and its complement KSC2690AYS in Melbourne. Great very linear transistors.

Hi All, Winovate has moved to 17 Metcalf Drive Dandenong South, 9792 1509, some years ago and while I am also working part time in Mentone I am still servicing ME amplifiers at Dandenong South. I Hope that clears things up. Ron.

PonyTail waves his hand, here for you in Melbourne, but Trevor is your man for Sydney and north, unless Peter Stein can help from Karanda. (way North) Currently my time for ME repairs is limited by other work and mostly by my mothers health, diagnosed this week with Gillian Barre Syndrome at 94 Years and 50 Weeks, so my attention span here is limited. Fortunately the IVIG treatment and respiratory support over NYE night seems to have helped, but there is a long way to go from paralysis to walking/driving again. Wishing A/all here a happy new year, and hope to be more active here on the forum when I can. Ron/PonyTail.

Yes

Hi Kerry, It would appear that you have a very early ME25 and the capacitors in the remote power supply have been known to fail especially at their age. I would recommend replacing these capacitors and all the electrolytic capacitors in the ME25 and upgrading the 470uF ones to 1000uF. The upgraded power supply (Identified by it using a 12-pin locking connector at the ME25 end rather than a 5-pin DIN connector) is not currently available along with its remote control option, but the above suggestion would offer some benefit. There is a possibility of adding an aftermarket Remote Control but unless your ME25 has the Alps balance and volume controls, this would be a very expensive option as the Balance and Motorized Volume control board from Peter Stein is very expensive.

Hi, I built this amplifier when it came out and it was still in everyday use until last year, still working but now not used. I should have a copy of both magazines, but I'm very sure I still have the December edition, bluish cover if I recall correctly. I'll take a look for them but if not inside then I need to search under the house which could take some time to find the time to search.