bias adjustment question jolida 502P

Is it necessary to readjust the bias on a jolida 502P tube amp after changing from 8 ohm speakers to 4 ohm speakers? The 8 ohm speakers were connected to the 8 ohm taps and I connected the 4 ohm speakers to the 4 ohm taps.
Hi Al2214

That is a good question. I own the Jolida 502P amp as well but have always had about 6 ohm nominal speakers so I've always used the 4 ohm taps to be safe. I think the one time I had 8 ohm speakers I just switched taps and then turned on the 502P. I had no issues at all. The only time biased jumped was when I switched out power tubes. I had NOS 6550 tubes and dialed down the bias and put in Tung Sol KT120s. I checked the bias and it was 700 millivolts.

Well I hope the A'gon vets can advise on this. Have you also tried calling Jolida? Maybe they can help after the holiday.
No, changing from a 4 ohm tap to an 8 will not affect your amp's bias, although it is good practice to check bias periodically as tubes age.