Aleph J-X Amp Project

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Marra

Member
Joined 2009
Paid Member
Is this the sort of thing that you mean.

HONEYWELL S&C|2455R-100-74|THERMAL SWITCH, NC, 70°C, 55°C | Farnell United Kingdom













SCAIFF001 said:
Hi Everyone,

I know there is a component that is attached to the output transistors heat sink and when it reachs a specific tempiture it cuts off the AC, or DC ?. What is this part called and what specifications should it have to be used in my Aleph J-X mono amps ?

I need to add this part because I relying on fans for cooling my amps and I dont have a way of determining if a fan malfunctions, which would result in thermal runaway ?

Thank You For Your Help

Ian
Click to expand...
 
Itsmee

Itsmee

Member
Joined 2009
Marra said:
Would the resetable type be better because it would cool down more quickly than the CL60 used for soft start and cause problems with current inrush?
Click to expand...

The heatsink would probably take longer to cool than the CL60, the advantage of the manual reset type would be in fault conditions - when generating more heat than normal, you choose when to reset and not the thermal switch.
 
SCAIFF001

SCAIFF001

Member
Joined 2010
Thermal runaway

Marra said:
I simply posed a question for scaiffoo1 which he has'nt answered
Click to expand...

Hi Marra,

Sorry for not responding to you immediatly after you sent the info to me I require, but I am stuck working between two different opperating systems currently due to a hard disc crash that I was not prepaired for,

Yes the component you suggested looks like it is what I am looking for, but the components distributer I have been useing has only the 80 degree thermalststs with a 65 degree reset, is the 80 degree trip point to high and I should look at a lower one of 65degree trip point, or should I look for other distributers and get the 70degree celcius one you suggested ?

http://canada.newark.com/jsp/search/productdetail.jsp?sku=98K8368

Thank You for your help

Ian
 
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SCAIFF001

SCAIFF001

Member
Joined 2010
Thermal Runaway

Marra said:
Yes RS was where I bought mine from some years ago although I tend to use Farnell these days.
When I built my Aleph 5 clone the schematic showed a 75 degree thermal switch and a 70 was the nearest I could get at the time.

Buy Temperature Sensors & Thermocouples Bi-metallic NO thermostat,Close@75degC Honeywell 2455R 82-712 F75C online from RS for next day delivery.
Click to expand...

Hi,

I hope I am ok with the 80 degrees because I think that 60 will be to low, concidering the schematic value of 75 degrees, I will not order the part today in case there is more information on the 80 degree being to high.

Thank You

Ian
 
SCAIFF001

SCAIFF001

Member
Joined 2010
Thermal Runaway

I ordered the 60degree Thermal Switch with a 45 degree reset based on information from Nelson Pass who states that the amp should not run hotter than 25 degrees above room tempiture, the hottest tempiture he describes to touch is 60degree celcius being "X*?@!", here the hottest day of the year is about 35 degrees celcius not including hummidity.

HONEYWELL S&C|2455R-100-85|THERMAL SWITCH, NC, 60°C, 45°C | Newark Canada
 
SCAIFF001

SCAIFF001

Member
Joined 2010
R16 to R23 components & thermal breakdown life

Hi everyone,

"Section 5." on "page 9 of 35" pages in "Eric's Aleph-X Amplifier Construction Notes"

Aleph-X 100w Amplifier Construction Notes

he states the the "Source Resistors For The Power Transistors" will dissipate alot of power, and he used three 5watt resistors to replace the one 3watt resistors.

I have justabout completed the mono amp enclosures and only have left to do is to souder stuffed the PCBs, so I can still make some changes, dose it make sence to substitute three 3watt resistors, beause the 5watt ones will not fit easily being 24mm & the 3watt being 14mm, for the the one 3watt resistors R16 to R23 ?

VISHAY DALE|RS02B1R500FE70|RESISTOR WIREWOUND, 1.5OHM, 3W | Newark Canada

Thank You For Any Comments Will Help

Ian
 
SCAIFF001

SCAIFF001

Member
Joined 2010
how matching R9 to R13, effect Q5 to Q8

Hi everyone,

I have just measured all of my 220ohm 1% resistors and have found them to very significantly in their precise value. What is the relationship between matching R9 to R13 to each relative Q5 to Q8, and let Q1 not be an issue at this time unless you would like to inform me on its effect as well ?

Thank You

Ian

(scatterbrain001)
 
SCAIFF001

SCAIFF001

Member
Joined 2010
[R9 to R13] relationship with [Q5 to Q8]

SCAIFF001 said:
Hi everyone,

I have just measured all of my 220ohm 1% resistors and have found them to very significantly in their precise value. What is the relationship between matching R9 to R13 to each relative Q5 to Q8, and let Q1 not be an issue at this time unless you would like to inform me on its effect as well ?

Thank You

Ian

(scatterbrain001)
Click to expand...

Hi,

I believe I was not very clear with the earlier question, and I will attempt to clear this up as follows: If the gate to source is lower than the average by 0.1% and the gate resistor is lower than the average by 0.1%, then will placeing these two components together converge towards the average or diverge from the average values measured ?

I need this to be resolved before I can sauder my circuit boards and complete the amplifier, sos any comment will help at this time.

Thank You For Replying If You Can

Scatterbrain001
 
nar

nar

Member
Joined 2002
SCAIFF001 said:
Hi,

I believe I was not very clear with the earlier question, and I will attempt to clear this up as follows: If the gate to source is lower than the average by 0.1% and the gate resistor is lower than the average by 0.1%, then will placeing these two components together converge towards the average or diverge from the average values measured ?

I need this to be resolved before I can sauder my circuit boards and complete the amplifier, sos any comment will help at this time.

Thank You For Replying If You Can

Scatterbrain001
Click to expand...

220R series = small value, doesn't really affect gate voltages or amplifier Operating Points

220R absolute value is not an issue, as the Gates don't consume large currents, in fact very tiny ones, so there is no dramatic V drop on those resistors, that could imbalance something in your design

Those are in place just to prevent some eventual parasitic oscilations, and even the value itself can be altered without a problem, as low as 47R or as high as 1000R, but in that last case it tends to reduce bandwidth

220R metal film 5% or 1% fits fine in 99,999999% cases ... no bother

Prefer metal film over carbon types for lowest noise.
On the contrary, some people prefer the sound of some types of carbon resistors, so YMMV

Best,

nAr
 
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SCAIFF001

SCAIFF001

Member
Joined 2010
Re: [R9 to R13] relationship with [Q5 to Q8]

nar said:
220R series = small value, doesn't really affect gate voltages or amplifier Operating Points

220R absolute value is not an issue, as the Gates don't consume large currents, in fact very tiny ones, so there is no dramatic V drop on those resistors, that could imbalance something in your design

Those are in place just to prevent some eventual parasitic oscilations, and even the value itself can be altered without a problem, as low as 47R or as high as 1000R, but in that last case it tends to reduce bandwidth

220R metal film 5% or 1% fits fine in 99,999999% cases ... no bother

Prefer metal film over carbon types for lowest noise.
On the contrary, some people prefer the sound of some types of carbon resistors, so YMMV

Best,

nAr
Click to expand...

Hi,

Thank You for your comments, they have reasured me to begin saudering.

Ian
[scatterbrain001]
 
SCAIFF001

SCAIFF001

Member
Joined 2010
schematic software

Hi,

I would like to know if anyone is familliar with "EDWinXP1.90" from Visionics ? I have access to this program but I was wondering if it is worth learning because it appears to be very complicated and will take many hours of learning over several years. I have the program loaded now, but am not shure if it is worth learning ?

Thank You

Ian
 
J

JLOP

Member
Joined 2011
Dear all

I am a french newbie here, sorry if not the right way :
- are they$re still Aleph J PCBs for 2 channels ?
- can someone explain the difference with the Krell KSA50 which had quite a lot of success it seems
- are they equally difficult to build ?
- will the Wiki be updated ?

I have Tannoy Rectangular GRF to drive.

Thanks a lot
Jean-Louis
 
SCAIFF001

SCAIFF001

Member
Joined 2010
JLOP said:
Dear all

I am a french newbie here, sorry if not the right way :
- are they$re still Aleph J PCBs for 2 channels ?
- can someone explain the difference with the Krell KSA50 which had quite a lot of success it seems
- are they equally difficult to build ?
- will the Wiki be updated ?

I have Tannoy Rectangular GRF to drive.

Thanks a lot
Jean-Louis
Click to expand...

There is allot to learn here with the people who have come b4 you, read and it is all here

Scatterbrain001
 
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