Special K Posted April 22 Posted April 22 (edited) Currently have an ME15 that needs some attention and looking for a schematic for it. Does anyone have a copy of this in a long shot? Thanks in Advance Keith Edited April 22 by Special K
Zaphod Beeblebrox Posted April 22 Posted April 22 10 hours ago, Special K said: Currently have an ME15 that needs some attention and looking for a schematic for it. Does anyone have a copy of this in a long shot? Thanks in Advance Keith No schematic is available, but one is not required. I've been servicing ME products for more than 40 years and have never required a schematic for an ME preamp. What is the fault with the ME15? I may be able to advise, or service the preamp for you. I note that you are in Melbourne, so Ron Berger at Winovate can service your preamp for you. He does not need a schematic either.
Special K Posted April 22 Author Posted April 22 (edited) 43 minutes ago, Zaphod Beeblebrox said: No schematic is available, but one is not required. I've been servicing ME products for more than 40 years and have never required a schematic for an ME preamp. What is the fault with the ME15? I may be able to advise, or service the preamp for you. I note that you are in Melbourne, so Ron Berger at Winovate can service your preamp for you. He does not need a schematic either. Ah! That makes sense why my tech could not fine one. It seems like the previous owner had a jumper in order to leave it on permanently, which I thought was rectified untill I had the unit was recapped. The response from my tech is that the power switch just disconnects the phono preamp. The unit will still work on cd and tuner. Just trying to rectify this currently and save my tech some fault finding time. Edited April 22 by Special K
Zaphod Beeblebrox Posted April 22 Posted April 22 So, there is no fault with the preamp? What are you trying to rectify? The operation you described is exactly how it was designed to be. Due to the lack of Global NFB, the ME15 should be left powered continuously. And yes, the jumper allows for the phono stage to be continuously powered as well. I do not advise willy-nilly replacement of electrolytic caps, unless it is performed by someone who knows ME products intimately. Some of the electrolytic caps are VERY carefully chosen for very specific performance parameters. Price and alleged reputation of capacitor manufacturers is not necessarily an appropriate guide either. Peter Stein went to very significant investigation in order to source the right capacitors for his products. Again, Ron Berger is your man to advise and properly service your ME15. He knows and has worked with ME products for more than 20 years. 2
Special K Posted April 22 Author Posted April 22 38 minutes ago, Zaphod Beeblebrox said: So, there is no fault with the preamp? What are you trying to rectify? The operation you described is exactly how it was designed to be. Due to the lack of Global NFB, the ME15 should be left powered continuously. And yes, the jumper allows for the phono stage to be continuously powered as well. So it is meant to not power off?! Why the power toggle then? The jumper is also default for these units? I was thinking something was wrong with the unit as it did not power off once the power toggle was switched to off.
Zaphod Beeblebrox Posted April 23 Posted April 23 The power switch turns the power light on and off, along with a connected ME power amp. The preamp is designed to be permanently powered on, as warm-up times are extremely long. This is all spelled out in the instruction manual. Yes, the jumper has been standard since the late 1980s. What types (brand and model) of electrolytic capacitors were replaced in your ME15?
Special K Posted April 23 Author Posted April 23 Understood! Thanks so much for this. I passed it on to the tech and he is all over it and understood as well. This is what was used for the recap. https://www.hificollective.co.uk/capacitors/elna-silmic.html It acted as others have described previously through the burn in time. However once settled, coupled with a Yammie M4 drove some lil audio drivers the best I’ve ever heard them.
Zaphod Beeblebrox Posted April 23 Posted April 23 1,000 hours @ 85 degrees C is not a good figure. In fact, it's pitiful. Personally I suggest that ONLY 5,000 + hours @ 105 degree C caps should be used. Fortunately, it's a preamp, so you should be OK for a few years, but be prepared to replace the lot in a few years. More critically I see no reference to leakage current. There are several capacitors in the ME15 that MUST be low leakage. If you examine the old capacitors (branded ME), you will note the letters: 'LL' on the cover. This indicates that they were specifically designed and built to be low leakage. For these reasons, I always recommend that ME products should only be serviced by techs with experience in the product. Even better is the fact that the right capacitors to do the job will invariably cost less than over-priced, so-called 'audiophile' ones. Take your ME products to Ron Berger next time. He knows what he is doing. 2 1
Recommended Posts