I was looking for a nice , cheap and small fonction generator for my circuits. It helps a lot when designing and debugging audio circuits. Most of them are old enough to be thru hole components , easily available parts and simple design. Today instruments are custom chip , highly integrated (not that easy to repair if you’re lucky and find the chip anyway )
It’s crazy how people go mad with those instruments, selling them for big money. I buy those instruments because there’re relatively old and therefore cheap ! I won’t spend 250 euros on a 30 years old budget fonction generator , I’ll buy a new one for that price ! I don’t give a shit about “vintage” , it’s an instrument , a tool not a relic or piece of art !
anyway , this Thurbly works good . it is simple and efficient . Small enough to fit everywhere. Of course it isn’t the purest and cleanest sinewave at high frequencies but good enough for what I’m doing right now.
The most odd thing being the on/off switch at the back….Really ? what for ? really annoying ! I don’t get the idea of this… The other (minor) thing being that there’s no Frequency read out on the front. You have to be close to see the Vernier . Of course I knew that when I bought it . There’s a TTL ouptut that will be used as an input for a home-made AVR frequency counter.
There’s also sweep in input , cool feature when designing filters !
Here are some pictures of the inside. We can cleary see that the PCB (labelled TG230 by the way) was a modular PCB for serveral product sharing the same topology. All thru hole components. The ICs are really commun , the CD3046 must the sine shaper IC . Also note the Styroflex cap , for stability and tolerance I guess.