UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Pre-amp for Linsley-Hood?

Radio Wrangler · 17th Mar 2019, 3:20 am

I'm not convinced the JFET gives any more gain. The unbootstrapped load in parallel with Zin of the follower times Gm. The bipolar beats it on Gm, but maybe he wanted to scale the Baxandall network for higher Z? It was in an era when transistors were still used sparingly. The 741 wasn't really up to the job, but later the NE5534 came along...

I notice JLH has his tape recorder output AFTER the volume and tone controls!

The WW series versus shunt debate was a little lively, but Hugh is a cool customer and sees maths as a useful tool. Noise analysis isn't terribly difficult and doesn't involve time-step calculations. If you want to see what Hugh did when he was getting serious, look up HP3745A in the HP journal.

David

17th Mar 2019, 3:20 am	#17
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,867	Re: Pre-amp for Linsley-Hood? I'm not convinced the JFET gives any more gain. The unbootstrapped load in parallel with Zin of the follower times Gm. The bipolar beats it on Gm, but maybe he wanted to scale the Baxandall network for higher Z? It was in an era when transistors were still used sparingly. The 741 wasn't really up to the job, but later the NE5534 came along... I notice JLH has his tape recorder output AFTER the volume and tone controls! The WW series versus shunt debate was a little lively, but Hugh is a cool customer and sees maths as a useful tool. Noise analysis isn't terribly difficult and doesn't involve time-step calculations. If you want to see what Hugh did when he was getting serious, look up HP3745A in the HP journal. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done Last edited by Radio Wrangler; 17th Mar 2019 at 3:26 am.