UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - "Tatiana" a clone of "Sweetheart" using Russian Rod Pentodes

neon indicator · 13th Aug 2011, 10:57 pm

Thanks Graham.

The Polish radio sometimes also called a "Sweetheart" aka "OP-3 Type 30/1" does look very similar, but the 2nd knob is near middle. It looks like a superhet. Is there a schematic anywhere? One just sold for serious money, nearly 1K, no logic to it really. I added photo of it to the blog / article.

Well, I will get the RF section working in next few days with 1j24b rather than the DF91/1T4 and see what it does. I suspect I might have slightly more tuning range (50% more capacitance, so maybe down to about 4.8MHz rather than 6MHz. Having somewhat more inductance to get down to 3.5MHz seems feasible.

It's not like it's a copy using identical coil, valves and tuning capacitors in a reproduction box. More a bit of fun using the identical design so adjusting the frequency band isn't a deal breaker?

I'll be happily surprised if I can resolve CW or SSB on it though!

13th Aug 2011, 10:57 pm	#3
neon indicator Retired Dormant Member Join Date: Jun 2010 Location: Co. Limerick, Ireland. Posts: 1,183	Re: "Tatiana" a clone of "Sweetheart" using Russian Rod Pentodes Thanks Graham. The Polish radio sometimes also called a "Sweetheart" aka "OP-3 Type 30/1" does look very similar, but the 2nd knob is near middle. It looks like a superhet. Is there a schematic anywhere? One just sold for serious money, nearly 1K, no logic to it really. I added photo of it to the blog / article. Well, I will get the RF section working in next few days with 1j24b rather than the DF91/1T4 and see what it does. I suspect I might have slightly more tuning range (50% more capacitance, so maybe down to about 4.8MHz rather than 6MHz. Having somewhat more inductance to get down to 3.5MHz seems feasible. It's not like it's a copy using identical coil, valves and tuning capacitors in a reproduction box. More a bit of fun using the identical design so adjusting the frequency band isn't a deal breaker? I'll be happily surprised if I can resolve CW or SSB on it though!