Xaudiox Amp Case
Hi, XaudioX - your amp looks gorgeous !! I've got this same case in brushed aluminum from a guy in Hong Kong. I'm curious as to the thermal resistance of these heatsinks - are you running NP's recommended bias current ? If so each of those heatsinks must be good for ~ 65 watts - that is good news.
I am using this same case for a balanced "double F5", but I am waiting for Russell Boss's new 2.5" deep heat sink extrusions, since I've got to dissipate ~ 130 watts per side. It should work, but the amp will be about 22" deep. I am going to mount the back plate 2.5" in side the back edge of the heat sink, so that the XLR connectors will fit within the envelope of the chassis and my cabinet !!
Hi, XaudioX - your amp looks gorgeous !! I've got this same case in brushed aluminum from a guy in Hong Kong. I'm curious as to the thermal resistance of these heatsinks - are you running NP's recommended bias current ? If so each of those heatsinks must be good for ~ 65 watts - that is good news.
I am using this same case for a balanced "double F5", but I am waiting for Russell Boss's new 2.5" deep heat sink extrusions, since I've got to dissipate ~ 130 watts per side. It should work, but the amp will be about 22" deep. I am going to mount the back plate 2.5" in side the back edge of the heat sink, so that the XLR connectors will fit within the envelope of the chassis and my cabinet !!
Re: Re: Re: Re: Re: hum F5
that the chassis is permanently connected to Safety Earth.
What about any other exposed conductive parts, like speaker terminals, or RCA input sockets, or metalised control knobs, or the far end of a speaker cable, etc?
Are they all permanently connected to the Chassis or to the Safety Earth after you switch in that break you have mentioned?
good.nigelwright7557 said:
that the chassis is permanently connected to Safety Earth.
What about any other exposed conductive parts, like speaker terminals, or RCA input sockets, or metalised control knobs, or the far end of a speaker cable, etc?
Are they all permanently connected to the Chassis or to the Safety Earth after you switch in that break you have mentioned?
Re: Re: Re: Re: Re: Re: hum F5
I was only suggesting the zero volts and earth should be disconnected when an earth loop occurrs. This means all the equipment is earthed elsewhere.
The alternative is to put up with hum from a ground loop.
Dont get too hung up on earths as a lot of UK equipment is just double insulated and is not earthed at all.
My disco cd player is not earthed yet is perfectly legal in the uK.
AndrewT said:
I was only suggesting the zero volts and earth should be disconnected when an earth loop occurrs. This means all the equipment is earthed elsewhere.
The alternative is to put up with hum from a ground loop.
Dont get too hung up on earths as a lot of UK equipment is just double insulated and is not earthed at all.
My disco cd player is not earthed yet is perfectly legal in the uK.
Double insulated does not require a Safety Earth
that's OK for certified double insulated equipment.
For standard equipment, we are required to ensure that all exposed conductive parts are permanently connected to Safety Earth.
There are no exceptions.
Back to the Safety question:
Are you suggesting that other builders break the exposed conductive parts connection to Safety Earth?
that's OK for certified double insulated equipment.
For standard equipment, we are required to ensure that all exposed conductive parts are permanently connected to Safety Earth.
There are no exceptions.
Back to the Safety question:
Are you suggesting that other builders break the exposed conductive parts connection to Safety Earth?
AndrewT,
We appreciate your cautions and safety notes, that should always be our first concern when we DIY. But ladd, your post was on the verge of an attack. At least that's how I read it.
Again, concern for safety is paramount, and should be.
I have no ground on my CD player either.
But; Goosefraaabaaa. (from the movie: Anger Management, very funny btw)
Ron
We appreciate your cautions and safety notes, that should always be our first concern when we DIY. But ladd, your post was on the verge of an attack. At least that's how I read it.
Again, concern for safety is paramount, and should be.
I have no ground on my CD player either.
But; Goosefraaabaaa. (from the movie: Anger Management, very funny btw)
Ron
Two questions:
1. If I already had 22V transformers lying around that gave me about 31-32VDC, what is the best course of action:
a. Order new ones anyway,
b. Run the amp at full voltage and back off the bias to keep dissipation manageable,
c. Run the amp at full voltage and full bias, and ensure the heatsinking can handle it, or
d. Regulate the supply rails with a pass transistor (not a pun!) and a zener or two.
Thanks for the input. Hope option 2 looks reasonable. I assume I will lose some power this way, and only get 30 watts or so in Class A. I'm actually OK with that. I will be using 1 c/w heatsink for each transistor, these are heavily finned 10" x 5" TO3 heatsinks (so have a blank mounting area running the length of the extrusion).
Four of these heatsinks will be used, I assume the additional 7 watts of dissipation will not be problem for them even if I ran the amp full tilt.
I mean to check my temperatures for a few days anyway, but would like to reuse these transformers if possible. They are rated to 10A continuous, are heavily overbuilt, and cost me a pretty penny.
I don't want to use regulated supplies if I can help it. The transistor market in India is guaranteed to throw fakes my way, and I'm not cool with blowing up any expensive devices or speakers.
2. I need a wee bit more gain. About 6-8dB will do it. Am assuming opamps will not cut it (I have some LM4562 laying about), any suggestions? I was hoping to build a small tube preamp for these if I could, but need some pointers (not ready circuits, more like a primer on tubes and how to set operating points and gain).
1. If I already had 22V transformers lying around that gave me about 31-32VDC, what is the best course of action:
a. Order new ones anyway,
b. Run the amp at full voltage and back off the bias to keep dissipation manageable,
c. Run the amp at full voltage and full bias, and ensure the heatsinking can handle it, or
d. Regulate the supply rails with a pass transistor (not a pun!) and a zener or two.
Thanks for the input. Hope option 2 looks reasonable. I assume I will lose some power this way, and only get 30 watts or so in Class A. I'm actually OK with that. I will be using 1 c/w heatsink for each transistor, these are heavily finned 10" x 5" TO3 heatsinks (so have a blank mounting area running the length of the extrusion).
Four of these heatsinks will be used, I assume the additional 7 watts of dissipation will not be problem for them even if I ran the amp full tilt.
I mean to check my temperatures for a few days anyway, but would like to reuse these transformers if possible. They are rated to 10A continuous, are heavily overbuilt, and cost me a pretty penny.
I don't want to use regulated supplies if I can help it. The transistor market in India is guaranteed to throw fakes my way, and I'm not cool with blowing up any expensive devices or speakers.
2. I need a wee bit more gain. About 6-8dB will do it. Am assuming opamps will not cut it (I have some LM4562 laying about), any suggestions? I was hoping to build a small tube preamp for these if I could, but need some pointers (not ready circuits, more like a primer on tubes and how to set operating points and gain).
Thank you, Mr. Pass 
Just the answer I was hoping for, I assume this would mean backing the bias off a bit would help. With the assumption that each transistor needed to be dissipating around 34 watts, at 32 volts operating voltage I would need to be at about 950mA per transistor to maintain similar dissipation levels, and be content with about 28 watts of total Class A power output.
I hope that this will keep the transistors from going into combustion. 28 watts is sufficient for me.
Just the answer I was hoping for, I assume this would mean backing the bias off a bit would help. With the assumption that each transistor needed to be dissipating around 34 watts, at 32 volts operating voltage I would need to be at about 950mA per transistor to maintain similar dissipation levels, and be content with about 28 watts of total Class A power output.
I hope that this will keep the transistors from going into combustion. 28 watts is sufficient for me.
Last night I tried to make comparative tests between the Zen V4 and F5, using a very well reviewed 5" full range of Italian production. The timbre of the two is slightly different, due to the high output impedance of the V4 (80 hom), but the thing that left me surprised, is that the soundstage of the F5 is at least 15" higher of the Zen one. Could someone try to explain me, the reason for this?
Both ampli with same cable, pre and cd player.
Thank you.
Both ampli with same cable, pre and cd player.
Thank you.
Steel mills supply mild steel with their mill specs indicating the yield strength of 235 N/sq.mm even if the test results are actually much higher than this value, e.g. 270 N/sq.mm or greater in most cases. Nevertheless, we apply the yielding exactly at 235 N/sq.mm, considering risk management with respect to "life", "property" and "environment" at sea.
The max. gate-drain voltage of 25V given in the datasheet of 2SJ108 reminds me of the similar feeling as above, but no such heavy risk . . .
Sangram, I believe that you would adjust the voltage rating of filter capacitors adequately.
The max. gate-drain voltage of 25V given in the datasheet of 2SJ108 reminds me of the similar feeling as above, but no such heavy risk . . .
Sangram, I believe that you would adjust the voltage rating of filter capacitors adequately.