I wish that I could compare the stock transformers to the Lundahl AM, but I ordered the Lundahl only and have never heard the stock opt. I understand that the amorphous core can take longer to settle in, so I am only sharing some preliminary impressions. Over the next few weeks, I will be taking my 8900 around to friends to hear it on a variety of speakers and systems.
Up until this point, my journey with tube audio has consisted of trade-offs between lush, rich and meaty textures and HiFi things like frequency response, resolution, placement in the soundstage, etc. I'm not sure if it's the 2A3, the Lundahl, or the design of the amp itself, but it is all working together beautifully on the 8900.
Up until this point, my journey with tube audio has consisted of trade-offs between lush, rich and meaty textures and HiFi things like frequency response, resolution, placement in the soundstage, etc. I'm not sure if it's the 2A3, the Lundahl, or the design of the amp itself, but it is all working together beautifully on the 8900.
I have finished my TU-8900 assembly last weekend. I have added a cooling fan on the two red boards.
for myself, I still like to see the board temperature drop from ~49oC down to ~30oC. I feel confidence when run this amp in the coming summer time.
Cooler temp is generally good to keep the electronic parts last longer. But how do u connect the fan to power and ensure the electrical noise from fan does not come into your amp system.
I used a 12V computer CPU cooling fan.
DC supply is used a 12V switching mode adapter.
A variable regulator and adjust the voltage to ~8.5Vdc.
On this voltage the fan running quite and not heard any noise from my Lowther PM6 speaker, and also not audible the fan noise from a distance of 1.5m.
DC supply is used a 12V switching mode adapter.
A variable regulator and adjust the voltage to ~8.5Vdc.
On this voltage the fan running quite and not heard any noise from my Lowther PM6 speaker, and also not audible the fan noise from a distance of 1.5m.
So are power transformer, OPT, heater, etc inside the amp. If we go that route, we will never be in state of happiness. So let’s back to our interesting TU-8900 topic 🙂
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Yes, but the difference is that transformers etc. were tested and optimized at Elekit unlike the fan and its connections. Layout changes can make significant difference. But I agree this topic has been overdiscussed.
I’m not sure why there is discussion of heat being an issue. My unit does not get hot enough to concern me in the least (either 2A3 or 300B), even running for 10 hours straight.
Oh boy, I finally got a chance to experiment with speakers. I borrowed a friends Zigmahornets (with the original Merrill drivers). These are only 90db/W sensitive and at first they were not cutting it in my large living room. But after I moved them into a bedroom in a mid-field configuration, my mind was blown. I couldn’t believe the detail and emotion pouring out them with my Cossor WE2A3. The small room load up the bass nicely on them, enough to enjoy. I was seriously playing Tool on them last night and rocking out hard.
Yea these are $600 project speakers, but they’ve shown me how special this amp that we have really is! I have a pair Omega Super 3 XRS on order. I’m sure I’ll also be engaging in some DIY speaker projects after this experience also. Thank you Victor!
Oh boy, I finally got a chance to experiment with speakers. I borrowed a friends Zigmahornets (with the original Merrill drivers). These are only 90db/W sensitive and at first they were not cutting it in my large living room. But after I moved them into a bedroom in a mid-field configuration, my mind was blown. I couldn’t believe the detail and emotion pouring out them with my Cossor WE2A3. The small room load up the bass nicely on them, enough to enjoy. I was seriously playing Tool on them last night and rocking out hard.
Yea these are $600 project speakers, but they’ve shown me how special this amp that we have really is! I have a pair Omega Super 3 XRS on order. I’m sure I’ll also be engaging in some DIY speaker projects after this experience also. Thank you Victor!
I would recommend trying the fullrangers in an open baffle configuration first (bass may be non existent for a driver that size. May need a large driver handling low end). I have found open baffle full rangers with tubes are quite special.
Thanks mchandra.
I consider heat issue is one of my experience in the early year when I repaired some cathode ray tube TV. Most the case caused the fault is due to long hour continue on heat, and caused some solder to dry joint or cracked on the cathode tube connector or on the high watt resistors. So, if we can bring the temp down, for me, it is a good thing to do.
@suO2, could you ditch the fan and figure out how to do passive cooling with strategically placed Aluminum heat sinks and vents?
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@SUo2.. Did you check all the test points? Are they within the spec in the manual?
When I have my demo amp in July, I turn it on for 10~12 hours per days for two months to burn in the Amorphous core. In July and August the temp in Vancouver are crazy hot TOO.
Mr.Fujita says...
HE Checked the temperature of the power module (the red PCB) with a thermo camera before the product was released and he confirm the heat is within the safe range. ...
If you still have concerns about the heat of your amp, I can arrange you to ship the main board to Mr Fujita's to check for you. It is not the spec of the amp to use heat ink or cooling fans..
When I have my demo amp in July, I turn it on for 10~12 hours per days for two months to burn in the Amorphous core. In July and August the temp in Vancouver are crazy hot TOO.
Mr.Fujita says...
HE Checked the temperature of the power module (the red PCB) with a thermo camera before the product was released and he confirm the heat is within the safe range. ...
If you still have concerns about the heat of your amp, I can arrange you to ship the main board to Mr Fujita's to check for you. It is not the spec of the amp to use heat ink or cooling fans..
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