Single Ended SUPPLY??
I wasn't really sure where to post this, so I sort of grabbed this quote. What about a single ended SUPPLY? The reason I ask is that I have a 48VDC battery source that seems ideal for powering it. I realize I could use a pair of resistors to create a virtual ground for the circuit as is, but there is one concern: My battery has the Neg pole connected to true Earth Ground, i.e. a 4' rod driven into the ground. I can run the + and - wires to the amp, create the virtual ground and even connect the chassis to the virtual ground (I think). Speakers won't care as they have no relationship with Earth ground. If I use my mp3 player as source, it has no relationship to Earth ground, so OK, BUT my CD player runs on AC and thus IS connected (eventually) to Earth ground. So, if I plug the RCA cable from the CD player to the amp I have a probelm, right? The CD ground on RCA is at Earth potential, but the RCA ground on amp is going to be at +24VDC relative to Earth. I could also run 3 wires from the battery bank: + (48V), middle (24V), and - (0V). That would create a true bipolar supply without using the resistor voltage divider, but I don't see how this will help the true Earth problem. Any thoughts? Other than input and output caps, what is needed to make the AlephJ run off a single ended 48VDC supply?The driver stage can be run balanced or single-ended. The output is single-ended. (As are your speakers...):
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I am familiar with the Quad and similar. My problem is I am not working from a transformer. My "power in" is +48VDC and 0VDC which is ALSO Earth ground. I can create a virtual ground half way between the two inputs, but that doesn't change the fact that the 0VDC lead is at Earth ground and I suspect that will cause a problem when interconnecting with other equipment (specifically a CD player). That is why I was asking about altering the circuit to run off a single ended supply. That may be an impossible or at least impractical task, but since amps like the Zen v9 run off a single ended supply, I thought it was worth asking.
that potential divider doesn't know and doesn't care is it fed from xformer and Graetz , or Niagara , or Moon , or accu stack
sole important thing is that you don't mix "grounds" with different energy/potential level
as long everything in every apparatus is floating , you can connect grounds together and have functional setup
if preceding devices (source, pre) are not safety grounded ( double isolated) , no reason to worry
and - you can always include line level xformer , where appropriate
sole important thing is that you don't mix "grounds" with different energy/potential level
as long everything in every apparatus is floating , you can connect grounds together and have functional setup
if preceding devices (source, pre) are not safety grounded ( double isolated) , no reason to worry
and - you can always include line level xformer , where appropriate
OK, agreed, no problem if everything floating. So other than disassembling the CD player, how can I determine if its output is floating? Can I check continuity between RCA ground and prongs of AC plug? What happens if I get it wrong and something IS at earth ground? Does something blow up?
I know this sounds dumb, but I am in US at the moment (which is where I can buy parts for projects) and my equipment is back in Panama. Probable chain would be CD player (don't rmemeber model number, but it is a Sony 400 CD changer) > jFET BoZ or B1 (I have the B1 and LOVE it, I now have the parts to finish my jBoZ) > AlephJ > JBL speakers (a home made version of the JBL Paragon). When I get ambitious I will probably bi-amp with a LR4 B1 based XO and ?? amp for bass. Other possible sources would be a SanDisc or Sony mp3 player, but they obviously are no problem.
Just to re-ask the question: Converting AlephJ to single ended power supply is not an option?
Great compliment to forum and DIY-shop
....it's a long, very long thread about Aleph J I read for month.
4 weeks ago I decided to realise my first Pass Amplifier. Listening with Aleph J of a friend of mine was a "mistake" - I never heard music so realistic and brilliant.
I bought via DIY shop the PSU and Aleph J boards and started the mechanical construction (Hifi2000-4U-400mm) using information in DIY shop and the forum.
10 days ago the board reached germany. After completing them I was very suprised, how exact the informations have been. EVERY screw was fine, I had a lot of fun, to build up the rest.
Today the thyroideal transformer reached and I couldn't wait, to finish.
Switching power on, now resistor got hot, every LED was okay and source resistors started with 500mV reaching 475mV after 10 minutes WITHOUT trimming R27.
Meanwhile both channels show 470 - 478mV over R-source Q5-Q8 - and Offset about 0,3/0,25 mV. That's great!!
And the sound: its difficult to describe, GREAT, WONDERFUL, PRESICE, MUSICAL!!!!!!
My thanks: Nelson Pass and his genial concept, DIY shop for EXACT informations, members of this wonderful forum with their constructive input.
Greetings from Germany
Meinolf
....it's a long, very long thread about Aleph J I read for month.
4 weeks ago I decided to realise my first Pass Amplifier. Listening with Aleph J of a friend of mine was a "mistake" - I never heard music so realistic and brilliant.
I bought via DIY shop the PSU and Aleph J boards and started the mechanical construction (Hifi2000-4U-400mm) using information in DIY shop and the forum.
10 days ago the board reached germany. After completing them I was very suprised, how exact the informations have been. EVERY screw was fine, I had a lot of fun, to build up the rest.
Today the thyroideal transformer reached and I couldn't wait, to finish.
Switching power on, now resistor got hot, every LED was okay and source resistors started with 500mV reaching 475mV after 10 minutes WITHOUT trimming R27.
Meanwhile both channels show 470 - 478mV over R-source Q5-Q8 - and Offset about 0,3/0,25 mV. That's great!!
And the sound: its difficult to describe, GREAT, WONDERFUL, PRESICE, MUSICAL!!!!!!
My thanks: Nelson Pass and his genial concept, DIY shop for EXACT informations, members of this wonderful forum with their constructive input.
Greetings from Germany
Meinolf
....well I try it, althoug the project is not completly finished. The definitive tyroideal transformer will reach next monday, the front will be wood, .....
But pictures show a lot of details (heating switch, loudspeaker protection and startup on back, power supply 32V for loudspeaker protect and relais construction in front,).
The transformer is a special one (4 x 19,5V - 6,5A / 24V 0,5A) from Rondo Müller Germany.
If heatsink would be higher than 70 degree, the power supply of transformer is switched off, unless temperature is lower 65 degree. Thats the reason I used 2 relais in front - they shorten or cut off powersupply. And the heating switch only switches 12V - not complete 230V.
Finishing next week I will post a few pictures more.
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I will be using a single ended input, but need a cap on the ground as well because it is really at +24V ? Something on the order of 1 uF?
Thanks for the offer of help. I will go ahead and get what I need to build the AlephJ now and build it when I get home.
jFET substitution
(I have some 2SK170s) If not, where can I get the SJ74s?
I searched, but could not find a post that addresses this: Is the 2SK170 a reasonable substitute for the 2SJ74? From their data sheets it would appear so to me, but ????
(I have some 2SK170s) If not, where can I get the SJ74s?