I'm looking to add a 12v trigger to my Elekit TU-8500. I can hunt around in there for some volts until I find something close - but I don't want to impact the sonic quality. Is there a place that makes sense to solder in the trigger jack? thanks!
https://tubedepot.com/products/elekit-tu-8500-stereo-tube-preamplifier-kit
another post
audiosciencereview guys had some decent suggestions, a Niles Current Sensing 12v trigger. I could put that inline with the AC into the preamp and that might do the trick.
12v trigger cable amazon
female (stereo) 3.5mm jack amazon, to hook up and hack into chassis.
https://tubedepot.com/products/elekit-tu-8500-stereo-tube-preamplifier-kit
another post
audiosciencereview guys had some decent suggestions, a Niles Current Sensing 12v trigger. I could put that inline with the AC into the preamp and that might do the trick.
12v trigger cable amazon
female (stereo) 3.5mm jack amazon, to hook up and hack into chassis.
Do you want a trigger input to switch on the amp, or a trigger output to switch on something else when the amp is turned on?
Jan
Jan
@jan.didden hahah, that IS a relevant question! The pair of mono locks do have a trigger, but I was thinking of turning them on with a trigger out of the preamp, the Elekit TU-8500.
That is relatively simple. If you have a schematic of the preamp, find some low voltage supply, and connect that to the monoblock trigger input.
In general, trigger inputs need 12V to turn on the equipment, so you need to be sure that the preamp output is dimensioned for 12V.
We can help with that if you can show the preamp schematic.
Hint: the preamp has a nice 12V source that can be used. But verify that the monoblocs indeed want 12V at the trigger input to switch on.
Jan
In general, trigger inputs need 12V to turn on the equipment, so you need to be sure that the preamp output is dimensioned for 12V.
We can help with that if you can show the preamp schematic.
Hint: the preamp has a nice 12V source that can be used. But verify that the monoblocs indeed want 12V at the trigger input to switch on.
Jan
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That would be fantastic. A bit of googling actually found someone else posted on this site:
http://skaju3.pro-linuxpl.com/Elekit-TU-8500-Circuit.pdf
for a remote module
ha, and I had posted it on my own blog at some point that I totally forgot about. page 15 of the manual is the same as the above link.
https://kerlee.com/blog/wp-content/uploads/2020/07/TU8500_English_manual_02_revised_1.pdf
http://skaju3.pro-linuxpl.com/Elekit-TU-8500-Circuit.pdf
for a remote module
ha, and I had posted it on my own blog at some point that I totally forgot about. page 15 of the manual is the same as the above link.
https://kerlee.com/blog/wp-content/uploads/2020/07/TU8500_English_manual_02_revised_1.pdf
Fun you mentioned that @jean-paul I read a review somewhere about upgrading those capacitors and a few other ones, and I did that!
https://kerlee.com/blog/?p=1079
Got the parts ordered for the 12v trigger. I'll update this thread with results. Thanks!
https://kerlee.com/blog/?p=1079
Got the parts ordered for the 12v trigger. I'll update this thread with results. Thanks!
Hi, I did not mention "upgrade" but "small value". With a meagre 0.47 µF a load of 25 kOhm is almost too low. So... in effect 99% of modern source devices have way better drive capability than this device.
Huh. I didn’t differentiate the meaning there.
Is there anything I can replace on the board to bring it more up to spec of modern devices? Maybe these lacking numbers have something to do with me frying F5T MOSFETs several times now?
Is there anything I can replace on the board to bring it more up to spec of modern devices? Maybe these lacking numbers have something to do with me frying F5T MOSFETs several times now?
Mmm, this is the proverbial tube device that needs to be "married" to a certain power amplifier with high input impedance as it simply has wimpy drive capability.
Please explain what that F5T is and what happens as you should not fry MOSFETs. Frying innocent MOSFETs is a bad habit. Before we go on... your TU-8500 does have a working/tested muting relay does it?!
Please explain what that F5T is and what happens as you should not fry MOSFETs. Frying innocent MOSFETs is a bad habit. Before we go on... your TU-8500 does have a working/tested muting relay does it?!
Yeah, I think I get what you’re saying there. It is a tube device, and it may be a bit wimpy, and there is perhaps nothing to be done about it. Might make more sense to sell it and get a different one.
The F5T is the Pass F5 Turbo MOSFET class A amp I built with loads of help from this forum. I turned it up too loud a couple times, one time with 8 amp fuse (face palm) and the MOSFET actually caught fire. This most recent time I pulled all the mosfets and tested them. Three of the eight were broken. I just replaced all of them.
But I was thinking that this preamp is what has been feeding the amp, perhaps it’s inadequacies are part of what led the failure.
The F5T is the Pass F5 Turbo MOSFET class A amp I built with loads of help from this forum. I turned it up too loud a couple times, one time with 8 amp fuse (face palm) and the MOSFET actually caught fire. This most recent time I pulled all the mosfets and tested them. Three of the eight were broken. I just replaced all of them.
But I was thinking that this preamp is what has been feeding the amp, perhaps it’s inadequacies are part of what led the failure.
Since I learnt that there are dodos in the tube world that remove muting relays I ask again: is the muting relay working OK at power on? So no slowly DC ramping up at the output destroying that Turbo device!? Also do you happen to know the input impedance of that Turbo device? Sorry but I stopped the cafeteria model, I can advise but only when all info is there.
If the Turbo device is DC coupled one should be extremely cautious having a working muting relay in the TU-8500. The power on and off sequence should also be: first TU-8500 on, then the Turbo on. Switching off: first Turbo off then TU-8500 off.
I also see the TU-8500 can output 22V rms . Maybe the Turbo chokes on that.
If the Turbo device is DC coupled one should be extremely cautious having a working muting relay in the TU-8500. The power on and off sequence should also be: first TU-8500 on, then the Turbo on. Switching off: first Turbo off then TU-8500 off.
I also see the TU-8500 can output 22V rms . Maybe the Turbo chokes on that.
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Good questions, and I don't know. A muting relay - I think that's a yes. The TU-8500 pre-amp flashes it's green light for about 10-20 seconds before making sound. I do not know the input impedance of the Turbo amp. But here I am hi-jacking my own thread, and monopolizing your time! I'm happy to stick with the 12v trigger for now 🙂 Thanks for your time!!!
IMHO you married the wrong devices. If the Turbo has enough gain of itself then you don't need any device adding gain and worse output drive in between. Your sources are likely perfectly capable to drive the Turbo. So source selection and volume control and maybe a buffer circuit could be enough.
You mentioned that the Turbos MOSFETs went to semiconductor heaven a few times when you turned it up too loud so maybe you could find out if the Turbo is able to survive 22V rms of tube magic. I think we know the answer.
You mentioned that the Turbos MOSFETs went to semiconductor heaven a few times when you turned it up too loud so maybe you could find out if the Turbo is able to survive 22V rms of tube magic. I think we know the answer.
There's NFB around that cap. So the naked 16Hz corner shifts down below 4Hz@-3dB, 8Hz@-1dB, and pretty flat for any musical purpose.