mike stehr

They can be good sounding little stand-alone amplifiers with the right speakers.

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Good sized iron for a El84 single-ended amp...

https://www.ebay.com/i/123320607001?ul_noapp=true They are all over eBay. The circuit uses the same power supply as the grounded grid line-stage circuit, but 260 vdc output instead of 200.

I've been toying with a Grounded Grid line-stage and power supply from Zero Zone. The GG boards do have an error, some are corrected. Things you have to pay attention to with these Chinese boards. Good sound for cheap with room for improvements... I bought the ZZ EAR834 tube phono-stage to try as well.

Gimme Chocolate

Wear your masks

The SYS is just a 10K stereo potentiometer in a box...it has no gain/output line voltage, meaning it's not an active device. The SYS just attenuates the line voltage from the source...like you mention. I'm guessing the ST70 amplifier requires a bit more input line voltage than your source puts out to get the best out of the amp...more than the common 2 volts from CD players and whatnot using the SYS. That's why the SYS sounds dead compared to the active preamplifier. I like that tone control option on the Erhard Aretha btw...

June 17th, 2001. I think the forums started in 1999...

Report post Posted 6 hours ago 09/14/2020 > SETI Said : A gift from IBSlammin. LuxmanPP triode 50ca10. Just completed cap replacement and putting it back to factory as it has been modified. Going to bring it up this week. I love the Luxman Me too...

A bread-board of this circuit, created by an retired EE audio friend of mine. Frustrated with the price of interstage transformers along with lousy bandwidth and goofy ratios, he experimented using a cheap Allied SE to PP interstage transformer connected as SE to SE. Square waves ring like crazy, until one bridges the interstage with the 0.1uF capacitor. The cap more or less brute forces the interstage to give better bandwidth, or gives the best of both worlds. (advantages of cap coupling and interstage coupling) It's a circuit that makes SET luddites cringe. But it will output a decent square wave at 30kHz, with strong bass at 30Hz. The 6EA7/bridged Allied IT front end circuit can run upwards of 120 volts peak to peak if I recall...I could be wrong. It's rather difficult to clip this amplifier for what it is. Personally, I think John Warren won this thread...

Breadboards? Here's a SRPP using a 6SL7 to drive a 71A. DC heating, because directly heating with 5 volts AC is a challenge I really doubt I can pull off. Polypropylene/oil caps used for cathode/filament bypassing. James universal OPTs. The circuit shined on my LaScalas I had at the time. Not much gumption at 800 milliwatts a side, but it sure had a nice sound.

From Kenosha, Wisconsin...heh

I kinda like it's little footies...

Japanese KS Musicmaster "Point one Five".

This old beast sounds rather good with my idler drive.