It's a Fen-Tone!

[Lucky Pierre]

Picked up this Fen-Tone Mark 8 amp yesterday. It about 1.5 watts, SE 35C5 with a hot chassis. I can't find any information anywhere on Fen-Tone, but it is remarkably similar to Monacor SA-10. Probably one of the late 60's Japanese manufactured amp that was sold under different names. And, yes, the bottom is cardboard.

Super long shot but any idea where I might find a schematic?

 

[Al Casey]

It seems that the amp has no power transformer but the mains is rectified.
Check the Mullard Seven-watt DC/AC amplifier schematic.

 

[Al Casey]

Here are the 35W4 rectifier and 35C5 datasheets

 

[zenith2134]

A stone cold classic! No, I've never seen or heard of it. I just love that these old units are still coming out of the woodwork in almost 2026

 

[dcgillespie]

Your time would likely produce more results by drawing out a schematic of it yourself, as l’ll bet you’ll find the needle (in the haystack) before you’ll find a schematic…….

Good luck with it!

Dave

 

[Lucky Pierre]

Your time would likely produce more results by drawing out a schematic of it yourself, as l’ll bet you’ll find the needle (in the haystack) before you’ll find a schematic…….

Good luck with it!

Dave

I have never done this, but I can give it a shot. I found the site SmartDraw. Any experience with it?

 

[Al Casey]

I have never done this, but I can give it a shot. I found the site SmartDraw. Any experience with it?

Okay Pierre, have a look at the Mullard seven watts amplifier; it’s the same principle: https://www.gammaelectronics.xyz/mullard_amps_1963_8.html
You don’t need a software to draw the schematic; the data sheets posted above will help you identify what’s connected on each pin; the heaters are connected in series.
A word of caution, there is no power transformer, the rectifier is directly connected to the mains.

 

[Lucky Pierre]

Thanks, Al!

 

[Tom Bavis]

There are 89 models listed on radiomuseum.org using those tubes, 81 of them providing schematics. There are two basic schematics, one for stereo, or push-pull for mono, with differences in the tone controls, use of feedback (see Motorola HS-703), some differences in component values. Stereo is simpler, same circuit twice. And one by Radio Shack has two 12AX7s - ignore that one! I could draw a schematic but would be guessing some values of resistors and capacitors.

 

[Bill Ashton]

From my recollection, Fen-Tone was one of those Japanese brands that small independant electronic stores sold in the early to mid 60's. First guitar pickup to make my cheap acoustic guitar electric was a Fen-Tone. I know they had a line of microphones, and pretty sure bits like cables and plugs.

Still have that old p/u, in its original box

 

[Lavane]

From my recollection, Fen-Tone was one of those Japanese brands that small independant electronic stores sold in the early to mid 60's. First guitar pickup to make my cheap acoustic guitar electric was a Fen-Tone. I know they had a line of microphones, and pretty sure bits like cables and plugs.

Still have that old p/u, in its original box

I had a small 6V6 PP.mono amps sold under the "Hi-Fi" brand. It was Also sold by Radio Shack, and had a few other brand names slapped on the same amp. It was acually a decent sounding little amp.
It was also a Japanese made amp.

 

[63pontiacgp]

"Hot" chassis, just like the radios I collect and work on.

Mike

 

[albusark]

So 35 x 3 + 12 = 117 volts. I love these designs. I was only previously aware of AA5 radio designs that were built with series filament, how interesting.