Little Dot I+ Headphone Amp

I'm hoping someone can help me solve a little issue I'm having with my amp. I got the Sennheiser HD58x jubilees which are rated for 150 ohms. So I decided to toggle the dip switches inside my little dop amp to be high impedance according to the Manuel's instructions. I'm using the stock bulbs and I haven't configured the jumper from how it shipped to me. I only flipped the dip switches to turn on high impedance as per the instructions. After doing this my headphones sound quieter. Not sure if that's a normal thing? Or if maybe my amp just had it dip switches installed backwards or something like that? and they were already set to high impedance when I came out of the box? I'm just asking if anyone else has experienced this.

This is utterly not true, the WE403A or B is from the EF95 family, the WE408A is its own branch. The LD mk1+ has instructions to change from 6j1/EF95 to 408A. However, as i was new to tube amp and saw comments like these on less reputable forums, I replaced my pair of 408A with the Voskhod 6j1p-ev and it fried the amp, the tubes and headphone were fine but the amp wasn't.

On the negative side, mine took 8 weeks to arrive. It shipped from China (I wish I had known that when I ordered it, I would have ordered from Amazon). I upgraded to the 6P tubes. I immediately ordered the Voskhod and 5654Ws. Tubes were waiting until the amp arrived. I rolled to the 5654W. It took some effort to open and switch the jumpers (I only did one jumper at first, then found the other later). This did improve the sound. Given the difficulty of switching tube families I will not be switching back to the 6Ps, but the Voshskod and 5654 are in the same family, and easy to “roll”. I also own the AAA789, but this seems as clean, and there does seem to be a bit if a “softness” on the edges of the tubes from this hybrid. Pairs really well with my headphones (HD6XXX, HE400i). Overall, a very solid amp!