Hi lgreen
I agree with AndrewT thoughts:
To me it more looks likes to be a HF pickup from your test leads or something not related to your amp ( HF at mains etc.... ). Try to measure with coupling at "HF-reject" What do you see? Any differences. Also try to alter your ground connection for your test-probe (you could use a separate ground connection to your scope). Also you could add a 100 ohms resistor between your test probes tip and measuring point to see if the oscillation is still visible (if still visible, well it could be from amp but not for sure)
Just my thoughts.
Regards 😎
I agree with AndrewT thoughts:
To me it more looks likes to be a HF pickup from your test leads or something not related to your amp ( HF at mains etc.... ). Try to measure with coupling at "HF-reject" What do you see? Any differences. Also try to alter your ground connection for your test-probe (you could use a separate ground connection to your scope). Also you could add a 100 ohms resistor between your test probes tip and measuring point to see if the oscillation is still visible (if still visible, well it could be from amp but not for sure)
Just my thoughts.
Regards 😎
True but the 465M is a completely different scope from the plain ole 465 or 465B. It only looks similar but completely different circuitry and such lies inside.
The 465B is by far the best of the pack and has LED's instead of incandescent light for all the indictors and dials.
Mark
Mark
i didn't say i wanted the M, you tought me to find a 465B.
But 100MHz and 50 nS/div horizontal with buttons that don't break off is still good.(i'm still playing with my boat anchor too much)
A 100MHz oscillation on the output reads funny.
i didn't say i wanted the M, you tought me to find a 465B.
But 100MHz and 50 nS/div horizontal with buttons that don't break off is still good.(i'm still playing with my boat anchor too much)
A 100MHz oscillation on the output reads funny.
lgreen
If it wasn't there before, when it was working, then maybe how you reconnected or positioned the wiring?
allan
If it wasn't there before, when it was working, then maybe how you reconnected or positioned the wiring?
allan
ok
Ok, i'll try what Flodstroem suggested to see if I'm just picking up RF, probably a lot of rf around here.
The changes to wiring were- (a) add new AC inlet, new wires run in same path as old, (b) add 1uF caps across electrlytics, (c) add 10K resistors across electroytics, (d) change Cap grounding- before all 4 caps connected to a terminal on one cap (ground) which went to star on chassis. Now L chan and R channel caps have own local ground and each then has a connection to star (chassis ground). Also, (e) reconnected L and R inputs inverted, so swapped connections at the boards to compensate, now black is - and white is +, but don't think color of wire should make a difference.
I thought the 465M was the same as 465B except ruggedized for military use? I've not had a problem with it other than the stand/handle on one side shearing off. I say "not good" because its specs are on the weaker end of the Tek line.
In my "travels" I've had occassion to "visit" one of their facilties in Beaverton, nice place, nice people. I've also been to LeCroy (NY) and the scope R&D plant at HP (now Agilent) in Colo. Springs. Same can be said of them as well, great places with great people.
Ok, i'll try what Flodstroem suggested to see if I'm just picking up RF, probably a lot of rf around here.
The changes to wiring were- (a) add new AC inlet, new wires run in same path as old, (b) add 1uF caps across electrlytics, (c) add 10K resistors across electroytics, (d) change Cap grounding- before all 4 caps connected to a terminal on one cap (ground) which went to star on chassis. Now L chan and R channel caps have own local ground and each then has a connection to star (chassis ground). Also, (e) reconnected L and R inputs inverted, so swapped connections at the boards to compensate, now black is - and white is +, but don't think color of wire should make a difference.
I thought the 465M was the same as 465B except ruggedized for military use? I've not had a problem with it other than the stand/handle on one side shearing off. I say "not good" because its specs are on the weaker end of the Tek line.
In my "travels" I've had occassion to "visit" one of their facilties in Beaverton, nice place, nice people. I've also been to LeCroy (NY) and the scope R&D plant at HP (now Agilent) in Colo. Springs. Same can be said of them as well, great places with great people.
ROVSING said:
Looks good! Are you using the BrianGT PSU boards? What caps do you have in there?
~Brad
Yes that is Brian GT PSU boards with 60000uF for each channel
It is 5$ capacitors, i personally don't believe in the more expensive the better - and i'll rather "blow up " cheap caps in the testing fase than expensive ones.
If you look at the right heatsink there is a metalplate "sticking out" my plan was to mount 2 or 3 psu coolers on that one (fore each side) but i don't really think its necessary - might be a little overkill.
Output fets will be mounted at a copper bar and then at the heatsinks.
Comparing my heatsinks with those mounted at the original, i think they are big enough - and coolingfan might not be necessary - psu fans don't give much air anyway.
I am trying very hard to make a WFD friendly design - and i hope i will succed on this one 😀
As an alternative i might mount 2 80 mm vans at the back of the amplifier - but that will ruin my design
It is 5$ capacitors, i personally don't believe in the more expensive the better - and i'll rather "blow up " cheap caps in the testing fase than expensive ones.
If you look at the right heatsink there is a metalplate "sticking out" my plan was to mount 2 or 3 psu coolers on that one (fore each side) but i don't really think its necessary - might be a little overkill.
Output fets will be mounted at a copper bar and then at the heatsinks.
Comparing my heatsinks with those mounted at the original, i think they are big enough - and coolingfan might not be necessary - psu fans don't give much air anyway.
I am trying very hard to make a WFD friendly design - and i hope i will succed on this one 😀
As an alternative i might mount 2 80 mm vans at the back of the amplifier - but that will ruin my design
ROVSING said:
Looks like a lot of the cooling surface of the heatsinks will be inside the chassis.
I hope you are aware of the thermo-dynamic consequences.
And i see another PinkMouse stand-off Krell, PTFE or Halma ?
Well actually one side of the heatsinks will be in the chassis, on the top of the heatsinks there is a slice in wich i will put a 4 mm ALU plate as the top of the chassis - with ventilationholes - maybe i could mount two 80 mm fans inside the chassis to pull the heat out of there - that wouldn't ruin the design that much - and now back to the drawing board....
The amount of heat that is radiated from a surface of a heatsink is determined by:
- the temperature difference between sink and ambient.
- the surface area.
- the thermal factor of the heatsink.
If your heatsinks can thermally be divided into three equal parts, the side that is inside the chassis will radiate 1/3d of the powerhandling, unless the temperature inside the chassis rises.
Means that if you wish to keep the temperature inside the chassis low and retain the nominal thermal factor of the heatsink you'll need to push a lot of heat out.
With a covering lid on top with holes, normal convection is not going to cut it.
- the temperature difference between sink and ambient.
- the surface area.
- the thermal factor of the heatsink.
If your heatsinks can thermally be divided into three equal parts, the side that is inside the chassis will radiate 1/3d of the powerhandling, unless the temperature inside the chassis rises.
Means that if you wish to keep the temperature inside the chassis low and retain the nominal thermal factor of the heatsink you'll need to push a lot of heat out.
With a covering lid on top with holes, normal convection is not going to cut it.
Thanks fore the advice Jacco
I don''t know the data of the heatsinks somone was so kind to give me 4 of those, if i understand you right fans will be a good idea - i'm going fore that and to make it even better ill make the inner sides of the "channels" in the bottom of the heatsink open - that will make the wiring easyer too, and then mount a pulling and a pushing fan on the top cover of the chassis with a small difference in the voltage supply - eventually adjustable to get the right balance.. that will give a lot of turbulense inside the chassis - thats good i suppose...
I don''t know the data of the heatsinks somone was so kind to give me 4 of those, if i understand you right fans will be a good idea - i'm going fore that and to make it even better ill make the inner sides of the "channels" in the bottom of the heatsink open - that will make the wiring easyer too, and then mount a pulling and a pushing fan on the top cover of the chassis with a small difference in the voltage supply - eventually adjustable to get the right balance.. that will give a lot of turbulense inside the chassis - thats good i suppose...
Hi,
did I see right?
Are the fins lying horizontal?
Stand the amp on it's tail or fit fans with ducting to ensure all the hot air gets outside.
did I see right?
Are the fins lying horizontal?
Stand the amp on it's tail or fit fans with ducting to ensure all the hot air gets outside.
Hi AndrewT
No matter how you place a heatsink heat goes up thats why you burn your fingers when you turn a lighter on upside down 😀
There is a lot of different opinions on this but what happens if you put the same heatsource on the bottom of a heatsink with vertical fins and on a heatsink with horisontal fins - both heatsinks with the same dissipationarea ?
Will there be any measureable difference ?
If you can prove to me why vertical fins should be better thats fine but i think this will do anyway, i got a gainclone running at home, chips are mounted on a massive ALU bar when i touch that on the opposite of the chip - it's coold when i touch it at the top it's hot.
Actually these heatsinks got "tree" form, you can see that at the top. I'm willing to take the risc.
No matter how you place a heatsink heat goes up thats why you burn your fingers when you turn a lighter on upside down 😀
There is a lot of different opinions on this but what happens if you put the same heatsource on the bottom of a heatsink with vertical fins and on a heatsink with horisontal fins - both heatsinks with the same dissipationarea ?
Will there be any measureable difference ?
If you can prove to me why vertical fins should be better thats fine but i think this will do anyway, i got a gainclone running at home, chips are mounted on a massive ALU bar when i touch that on the opposite of the chip - it's coold when i touch it at the top it's hot.
Actually these heatsinks got "tree" form, you can see that at the top. I'm willing to take the risc.
Jacco
Sorry i didn't answer your other question it's Halma -
in honour for the PCB designer, my kids didn't notice that i took them...😀
Sorry i didn't answer your other question it's Halma -
in honour for the PCB designer, my kids didn't notice that i took them...😀
2000VA transformer
HI
I would like to ask a question from those people who orderd transformer fro the audiohobby guy if everibody receved it .
I orderd a transformer a couple weeks a go for the Krell clone but until now I did not receved yet .
I wrote some email to the him but he does not answer to me .
Just to be clear why I'm worried not just no answer , and no transformer , he closed his site and he close at the Audiogon site to .
Please let me know if you are in the same shue like me .
Thanks
HI
I would like to ask a question from those people who orderd transformer fro the audiohobby guy if everibody receved it .
I orderd a transformer a couple weeks a go for the Krell clone but until now I did not receved yet .
I wrote some email to the him but he does not answer to me .
Just to be clear why I'm worried not just no answer , and no transformer , he closed his site and he close at the Audiogon site to .
Please let me know if you are in the same shue like me .
Thanks
Hi rov,
look up any data sheet from the manufacturer and you will find that at least 25% of the dissipation capacity is lost if you mount the fins horizontal.
The effect of this is that the devices WILL run hotter.
But you can alleviate that by blowing air through the sink.
look up any data sheet from the manufacturer and you will find that at least 25% of the dissipation capacity is lost if you mount the fins horizontal.
The effect of this is that the devices WILL run hotter.
But you can alleviate that by blowing air through the sink.
Hi AndrewT
Well this heatsink is not only with horisontal fins, i haven't read any data on any heatsinks, do they tell anything about how much dissipation will be improoved if the heatsink are painted black ?
I will mount fans just to be sure, but the heatsinks are pretty big
360*120*80 mm.
Well this heatsink is not only with horisontal fins, i haven't read any data on any heatsinks, do they tell anything about how much dissipation will be improoved if the heatsink are painted black ?
I will mount fans just to be sure, but the heatsinks are pretty big
360*120*80 mm.
Those are very nice heatsinks, though I must admit I'm not entirely sure how you are going to mount that arrangement of PCBs on them with the case configured like that. 😉