I have a few chassis that could use new amp circuits. Power supply voltages range from +-60 and +-85V.
2017 Sanken 2.0 Stereo Daul channel HIFI Power amplifier board Finished 500+500W | eBay
Any recommendations would be nice!!
2017 Sanken 2.0 Stereo Daul channel HIFI Power amplifier board Finished 500+500W | eBay
Any recommendations would be nice!!
How many fake Asian tranneys on that board ?
Would you trust your speaker voice coils to find the answer ?
Would you trust your speaker voice coils to find the answer ?
That looks like a 2pair output stage with Sanken double bolt 200W transistors.
I estimate the maximum reliable output power to be around 160W.
If you want to live right on the edge of reliability, then you might try pushing the amp to around 300W, but never 500W from a ClassAB output stage.
500w into 8ohms requires 63vrms. The amp is indeed forced air cooled like some pro audio amps, and for $80, it such a small price that maybe a dummy load burn in test might be worth it to see if it indeed musters 500w? If you can find equivalent item on Aliexpress, they have very good buyer protection. Simply show some photos as proof of the amp with fizzled charcoal outputs and photo of test with dvm at 63vrms with dummy load. Make sure you don't click the "received" button before you run the test, the funds are still in escrow so much easier for Aliexpress to arbitrate in your favor. You will get your money back. Then replace the Sankens and use the amp at 300w as AndrewT suggests. So it either works or you get a free amp with dead fake Sankens.
But if you are really bent on 500w (only a PA application needs that much) then get an IRS2092 Class D. They are very reliable and sound excellent. Here is one from LJM.
Finished L15DX2 IRS2092 CLASS D AMPLIFIER IRAUDAMP7S 125W-500W by LJM | eBay
But if you are really bent on 500w (only a PA application needs that much) then get an IRS2092 Class D. They are very reliable and sound excellent. Here is one from LJM.
Finished L15DX2 IRS2092 CLASS D AMPLIFIER IRAUDAMP7S 125W-500W by LJM | eBay
Last edited:
I believe the same board is available for around half that if you look further.
I had a choice of either that board, or this one;
1PC NJW0281/NJW0302 450W+450W HIFI Stereo Amplifier Board Assembled AMP Board | eBay
That board shown in the above link had stability issues, and I didn’t want a repeat performance with another un-tested arrangement, so have shelved the project for now.
I’ve put eBay amp boards in the same classification as retreaded tires I’m afraid, good luck if you try it though, would be interested to see if it would work out.
I had a choice of either that board, or this one;
1PC NJW0281/NJW0302 450W+450W HIFI Stereo Amplifier Board Assembled AMP Board | eBay
That board shown in the above link had stability issues, and I didn’t want a repeat performance with another un-tested arrangement, so have shelved the project for now.
I’ve put eBay amp boards in the same classification as retreaded tires I’m afraid, good luck if you try it though, would be interested to see if it would work out.
I am glad to see someone else agrees.
A dual 40Vac transformer would be great for an 8ohms capable amplifier. This should give somewhere between 150W and 170W into 8ohms (reactive) depending on the mains voltage.
A dual 35Vac transformer would allow for driving a reactive 4ohms load.
Maybe around 200W in 4ohms, again depending on mains voltage.
Hi and bump! Haven't been here in a while. I've been looking at this headphone amp: Nobsound NS-08E Vacuum Tube Headphone Amplifier Hi-Fi Valve Headphone Amp Stereo Audio Preamplifier https://www.amazon.com/dp/B014FASL1A/ref=cm_sw_r_apan_i_BFEZWFTQE2VZWAP1GX3H?_encoding=UTF8&psc=1
And was wondering how it would compare to this one on eBay?
https://www.ebay.com/itm/3139188368...spIgLxWR5a&var=&widget_ver=artemis&media=COPY
It will be used with my Hifiman 400i 2020 headphones and my Cayin N3 or Hiby player. Thanks in advance.
And was wondering how it would compare to this one on eBay?
https://www.ebay.com/itm/3139188368...spIgLxWR5a&var=&widget_ver=artemis&media=COPY
It will be used with my Hifiman 400i 2020 headphones and my Cayin N3 or Hiby player. Thanks in advance.
This is the solid state forum. The two appliances shown in post 11 appear to have two vacuum tubes each. My PAS2 preamp has 4 vacuum tubes, a very nice steel encased transformer with filament & AC wiring put in a separate steel enclosure from the actual audio circuitry, to cut the hum from that wiring. These two devices appear to have no transformer whatsoever, or one that operates at kilohertz or megahertz instead of 60 hz. So inside these would be some sort of switcher supply. I've found pro switcher supply class AB amps (Peavey, QSC, Allen organ) with no RF howl in the output have the switcher parts in a separated grounded steel box from the class AB parts, with filters on all wires coming out. These two appliances are too tiny to have much of anything inside. So if you like to listen to a whistle in your headphone for a few hours before the switcher supply melts something. spend your money. If you purchase one the good news is that most males over age 12 are deaf above 7 khz anyway and won't hear any switcher noise.
I've found my legendary 1961 PAS2 with 4 12AX7 tubes sounded great for 40 years with ecap & rectifier improvements. But after the paper capacitors deteriorated, the off value (.22 uf instead of original .20) polyester replacement caps sounded funny. I get much better sound from a op amp RIAA mixer using 33078 (instead of original 4558) that consumes 5 watts instead of 100. So there my four 12AX7 project went to the attic for the future. Can't get original loudness compensating volume control anyway. At least my 1961 transformer didn't melt a bunch of components inside, the way cheap switcher supplies are destined to do. The ebay & amazon appliances don't have any apparent source switching or LP capability at all, just perhaps a line level (1.6 vac) to headphone level (7 vac) voltage boost with current boost. Very modest current boost considering these aren't final stage tubes like 6BQ5 or 6CA7 or 6L6.The vacuum tubes may instead be just decorations.
I've found my legendary 1961 PAS2 with 4 12AX7 tubes sounded great for 40 years with ecap & rectifier improvements. But after the paper capacitors deteriorated, the off value (.22 uf instead of original .20) polyester replacement caps sounded funny. I get much better sound from a op amp RIAA mixer using 33078 (instead of original 4558) that consumes 5 watts instead of 100. So there my four 12AX7 project went to the attic for the future. Can't get original loudness compensating volume control anyway. At least my 1961 transformer didn't melt a bunch of components inside, the way cheap switcher supplies are destined to do. The ebay & amazon appliances don't have any apparent source switching or LP capability at all, just perhaps a line level (1.6 vac) to headphone level (7 vac) voltage boost with current boost. Very modest current boost considering these aren't final stage tubes like 6BQ5 or 6CA7 or 6L6.The vacuum tubes may instead be just decorations.
Last edited:
