B1 w/ jensens

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Not really. Only about 91 dB/W. Just with music recorded at low levels it happens sometimes that it is too quiet. But normally it is getting loud enough for me in 99% of the cases.

For some time I had a scope attached to the output of the B1. I do not think that I have seen much higher amplitudes than 2 V. I think Nelson is absolutly right with his first watt approach. :)
 
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I didn’t see any info on first watt.com and thought there might have been a small production run of the B1s with transformers. It’s disappointing to hear about the back story that it was a gift that was not appreciated for what it was. I inquired about it because it looked like the prototype from Burning Amp but it was already sold on eBay. I’ll just have to live with my cobbled together DIY version :D Altec 15335As can still be found at reasonable prices (I got a whole box of them years ago for cheap), probably because they don’t have center taps. They work great if you only need 6dB of gain. I connected them to the output of my DIY B1. The nice thing is you can add them to you existing B1 without any mods.

2 15335A
2 octal relay sockets
2 RCA patch cables cut in half
2 jumpers
(I also put resistors across the outputs to keep the load ~15k to maximize bandwidth)
 

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I am the guy who bought this B1 preamp. Little did i know that it might have a history. After pondering its origins and searching the net, I came upon this thread. So, I offer what I know to the conversation.
I was looking for something with some gain to substitute for my B1 (sn 3181). It arrived from Korea in a box just like that used for my B1 and B4 crossover. Handwritten on the box is "B1 #333) along with some shipper history. Before Korea it was in Delaware. and prior to that in Minn. No names.
The preamp itself looks very similar to my production B1. Similar build inside as you can see from the ebay posting. No First Watt script on the face plate and no serial number anywhere. It is powered by a hardwired 24VDC ELPAC. Sounds fine, only one small oddity. The two channels seem to have slightly different gain. When the left knob is at eight o'clock, the right side needs to be at nine to have balance.
So that is my story. Perhaps it will help solve this minor mystery. If it is the prototype, fine. If a DIY, nice job!
 
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