30 degrees C difference is a lot. That would be about 50 degrees C or so. That is very hot.
How did you determine the temperature difference? Infrared thermometer? Contact thermometer? By touch? It would feel very hot.
How did you determine the temperature difference? Infrared thermometer? Contact thermometer? By touch? It would feel very hot.
Yes by infrared thermometer, and it's in the low 50's (c) with the ambient around 18c.
I've already re-flowed these two resistors and the adjacent transistors and capacitor.
I'm not sure where to look next?
I've already re-flowed these two resistors and the adjacent transistors and capacitor.
I'm not sure where to look next?
Have you confirmed the temperature by another method? A cooking thermometer? A thermocouple thermometer?
By hand? 50 degrees C is crikey hot, 5 seconds hands on:
The Aleph-X
The hottest components are probably the JFETs, which are located close to the resistors. Perhaps your infrared thermometer is picking up their temperature.
But I don't think any components other than the Korg would get that hot.
By hand? 50 degrees C is crikey hot, 5 seconds hands on:
The Aleph-X
The hottest components are probably the JFETs, which are located close to the resistors. Perhaps your infrared thermometer is picking up their temperature.
But I don't think any components other than the Korg would get that hot.
Last edited:
Thanks for sticking with me Ben.
All I had was a BBQ probe. Crude, but found the following:
270R 56c (13.64v drop)
10R 32c (T2-T3)
10R 25c (T1-T2)
Zener 31c
100R 31c
R1 33c
Q1 33c
Q2 29c
The 270 was the only resistor on the board that felt truly hot.
All I had was a BBQ probe. Crude, but found the following:
270R 56c (13.64v drop)
10R 32c (T2-T3)
10R 25c (T1-T2)
Zener 31c
100R 31c
R1 33c
Q1 33c
Q2 29c
The 270 was the only resistor on the board that felt truly hot.
So no 50 degrees C at R1 and 100R. That's good. Infrared thermometers can be tricky to use.
A BBQ temperature probe works although it may be a bit slow because of its thermal mass. I use a cooking thermometer for measuring component temperatures. It's diy so use whatever is available.
The 270R 3W resistor has the Korg tube filament current through it and combined with the higher resistor value, it is understandable that it gets hot.
270R resistor power dissipation = (13.64V)(13.64V)/270R = 0.69W
That will raise the temperature of a 3W resistor.
So your B1 Korg is working as it should, with no worries. 🙂
A BBQ temperature probe works although it may be a bit slow because of its thermal mass. I use a cooking thermometer for measuring component temperatures. It's diy so use whatever is available.
The 270R 3W resistor has the Korg tube filament current through it and combined with the higher resistor value, it is understandable that it gets hot.
270R resistor power dissipation = (13.64V)(13.64V)/270R = 0.69W
That will raise the temperature of a 3W resistor.
So your B1 Korg is working as it should, with no worries. 🙂
Thanks again Ben, this has been an education.
I'll do a bit more digging on using the IR thermometer properly.
I'll do a bit more digging on using the IR thermometer properly.
IR thermometers are sensitive to the color of the object.
I try to read temperatures off dark surfaces.
I try to read temperatures off dark surfaces.
Pass DIY Addict
Joined 2000
Paid Member
Jon: glad to hear you don’t really have a problem! This is the best outcome of all. Another troubleshooting approach to use (though this won’t work for the filament resistor because there is only one) is to compare voltages and temps across both channels since they are right there next to one another.
Given that the 270R gets warm, it’s good that you positioned it on the board with a little air space under it to aid with keeping cool.
Given that the 270R gets warm, it’s good that you positioned it on the board with a little air space under it to aid with keeping cool.
Thanks Eric, I'll certainly keep this in mind - although I'm not planning another build... said no one here.
What a community.
Any harm in using a plastic Zeneer in4739? I forgot to order and was only able to get a plastic one locally.
Hello everyone, while (im)patiently waiting for a B1k PCB to arrive, I've been reading through 200 pages of this thread, give or take...so hopefully I won't be asking questions that have already been asked. I've started to gather the components, mainly through Mouser and a few other sources and I have a couple of questions:
Luca
- am I right to assume that the PCB is of "standard" (1.57mm / 0.062 in) thickness? I'm only asking because I'd like to use a pretty compact enclosure that allows to slide the PCB onto some sort of slot.
- just like many others, I've ordered only 2x 100ohm resistors. However I happen to already have a few 100ohm (1/2w) but with a 5% tolerance, and they measure about 96ohm. Would that be okay or is it crucial to stay within the 1%?
Luca
1. Yes
2. Not crucial, like most of the other values. Because of variations in nutube and fets, all the voltages are just good approximations, so if you want precise results you have to measure the distortion.
2. Not crucial, like most of the other values. Because of variations in nutube and fets, all the voltages are just good approximations, so if you want precise results you have to measure the distortion.
Hi all, very loving this preamp built from kit. Bit of a troubling issue possibly unlrelated to the build but all help appreciated.
I have a home energy management system that communicates over powerline ethernet to a smart hot water tank. When the gateway and tank are on (they're each on separate mains circuits), there's audible hash coming out of the preamp. Turn the tank off, still there (different noise), turn the gateway off and ahhhhhh, quiet. No other audio system in the house suffers this problem.
The wallwart is plugged into a filtered powerboard. Deleting the powerboard doesn't change that, neither does swapping the wallwart for a minty-mint Meanwell 24DC item.
The hash is most audible when the volume is set at minimum.
Any ideas?
I have a home energy management system that communicates over powerline ethernet to a smart hot water tank. When the gateway and tank are on (they're each on separate mains circuits), there's audible hash coming out of the preamp. Turn the tank off, still there (different noise), turn the gateway off and ahhhhhh, quiet. No other audio system in the house suffers this problem.
The wallwart is plugged into a filtered powerboard. Deleting the powerboard doesn't change that, neither does swapping the wallwart for a minty-mint Meanwell 24DC item.
The hash is most audible when the volume is set at minimum.
Any ideas?
No can do. Hot water tank is powerline eth, and very chatty.
Trying to get an understanding of what's causing this; signal route ATM is DAC>pre>active speakers, when I bypass the pre and go DAC>actives... not a peep. Dead quiet. Very odd. Any ideas?
@rmpfyf
I don't understand why you used single twisted pair for L & R signal and another single twisted pair for signal ground of L & R on input RCA, that is conceptual wrong.
Twisted pair should carry only left (or R) hot and signal GND, other twisted pairs should be for rest of the RCA connectors. Twisted pair have function to minimize interference picked from nearby wiring. Is your case grounded? don't see well what type of power socket it is, is it isolated from case? If not isolated then you have power GND connected to the case and you form protection from outside RF signals or interference. Is your case anodized aluminum? If yes, then you should on some way enable good electrical connection between parts of the case to comply Faradey cage.
I don't understand why you used single twisted pair for L & R signal and another single twisted pair for signal ground of L & R on input RCA, that is conceptual wrong.
Twisted pair should carry only left (or R) hot and signal GND, other twisted pairs should be for rest of the RCA connectors. Twisted pair have function to minimize interference picked from nearby wiring. Is your case grounded? don't see well what type of power socket it is, is it isolated from case? If not isolated then you have power GND connected to the case and you form protection from outside RF signals or interference. Is your case anodized aluminum? If yes, then you should on some way enable good electrical connection between parts of the case to comply Faradey cage.
@pitbul thanks much for this reply.
The twisted pairs confused me also, it's wired as per the build guide https://guides.diyaudio.com/Guide/B1+with+Korg+Nutube/12
Power socket is just a usual plated 2-pin barrel jack carrying 24VDC. Case is the kit case as per that build guide (anodized aluminum). I haven't e.g. taken off any anodising around the barrel jack for continuity to the chassis; will test tomorrow (~3AM here) but it may be isolated from the case.
Is anyone else with the kit doing differently? Did I miss anything obvious?