Hello All,
Richard (SumR) from Primrose was kind enough to call me this morning with regard to the toroidal I purchased from him. After explaining the issue I was having and the project I was working on, he let me know that he was very aware of the Nelson Pass amplifiers and designs, and he is confident he would have a transformer solution for my needs and would put a new transformer into production for me. Super friendly gentleman and easy to speak to.
Richard (SumR) from Primrose was kind enough to call me this morning with regard to the toroidal I purchased from him. After explaining the issue I was having and the project I was working on, he let me know that he was very aware of the Nelson Pass amplifiers and designs, and he is confident he would have a transformer solution for my needs and would put a new transformer into production for me. Super friendly gentleman and easy to speak to.
glad to hear
btw. almost foolproof recipe , when ordering custom xformer (not just for custom voltages , but in case when you're ordering something just not being on the shelf) - demand (for instance ) 250VA Donut , made on 300VA core
if you want , make that difference even bigger , taking care of your minimal figure being regular overkill
that way magnetic flux is lesser and less chance of xfrmer buzz
for my understanding - so called "Audio grade" xformers are made in exact that way
however , when having standard xformers already from the shelf , "all" you need is luck
btw. almost foolproof recipe , when ordering custom xformer (not just for custom voltages , but in case when you're ordering something just not being on the shelf) - demand (for instance ) 250VA Donut , made on 300VA core
if you want , make that difference even bigger , taking care of your minimal figure being regular overkill
that way magnetic flux is lesser and less chance of xfrmer buzz
for my understanding - so called "Audio grade" xformers are made in exact that way
however , when having standard xformers already from the shelf , "all" you need is luck
I used SUMR 24 x 2 1000 VA in my BA3 power amp, cant tell if it is on or not, sooo quiet!
Russellc
Now for my Aleph J build review. After installing the new transformer into the chassis, I warmed up the amp and double checked the bias and offset, all was spot on. I hooked up my speakers, a vintage pair of JBL L150's (with a sensitivity of 89db), and powered up the Aleph J. The source is currently the dac from my Apple airport express (connected directly to the amp inputs) streaming music via Ethernet or air-played from my iPhone.
I sat down to listen to some of my favourite songs, and others I use as "reference" when listening to audio equipment. At first the sound seemed a little bright compared to what I've been accustomed to hearing from my speakers, but I continued to flip through songs and listened carefully. After about an hour things began to change. The music seemed much fuller, warmer. So I went back and started listening to the same songs I'd started off with.... what a difference!!! I cannot begin to explain how good the same tracks now sounded! It seems that the J likes a little warm up time, at least in my case. Those 25watts of Class A power sound much bigger than I'd expected, and play excellently with my JBL's. Playing "As hope and promise fade" from Chris Cornell's acoustic Songbook cd placed me right in the middle of the concert hall as if I was right there... Amazing. Thanks Mr. Pass for providing all of us with an amazing amplifier, and to everyone at the DiyAudio site that puts in so much effort to give guidance and advice (big shout outs to 6L6 for his build guides, and Zen Mod) to diy'ers to make audiophile grade gear that lives way past our expectations!
Now what to build next????
I sat down to listen to some of my favourite songs, and others I use as "reference" when listening to audio equipment. At first the sound seemed a little bright compared to what I've been accustomed to hearing from my speakers, but I continued to flip through songs and listened carefully. After about an hour things began to change. The music seemed much fuller, warmer. So I went back and started listening to the same songs I'd started off with.... what a difference!!! I cannot begin to explain how good the same tracks now sounded! It seems that the J likes a little warm up time, at least in my case. Those 25watts of Class A power sound much bigger than I'd expected, and play excellently with my JBL's. Playing "As hope and promise fade" from Chris Cornell's acoustic Songbook cd placed me right in the middle of the concert hall as if I was right there... Amazing. Thanks Mr. Pass for providing all of us with an amazing amplifier, and to everyone at the DiyAudio site that puts in so much effort to give guidance and advice (big shout outs to 6L6 for his build guides, and Zen Mod) to diy'ers to make audiophile grade gear that lives way past our expectations!
Now what to build next????
JSA: That is great news. Dennis Hui gave some good advice. When I first ran my AlephJ, I also came directly out of a DAC. Eventually, I built a Gyrator loaded Son of ZV9 preamp, which has some gain (using a 10K pot), and the AlephJ sounded even better than coming from the DAC alone. Do not ask me to explain why. 6L6 has commented that he likes using the BA3 preamp which has some gain. There are others. Maybe the next biggest bang for your buck will be one of those preamp builds.
Member Tea-Bag has offered PCBs, along with the Edcor transformer (super convenient) in a GB:
http://www.diyaudio.com/forums/grou...ds-120mm-ums-spacing-tea-bag.html#post4612640
If you're interested, PM him as he may still have some available.
Cheers,
Dennis
http://www.diyaudio.com/forums/grou...ds-120mm-ums-spacing-tea-bag.html#post4612640
If you're interested, PM him as he may still have some available.
Cheers,
Dennis
Hi all,
Just finished my Aleph J's: revised with some extra heat sinking (double...) and capacitance (now 220.000uF/channel).
It's alive... and they sound nice.
The bias is raised to 470mV (this is the highest I can get it with the pot... anyone know how to get it to, let's say 500mV?; the heatsinks seem to allow for a higher bias).
Just finished my Aleph J's: revised with some extra heat sinking (double...) and capacitance (now 220.000uF/channel).
It's alive... and they sound nice.
The bias is raised to 470mV (this is the highest I can get it with the pot... anyone know how to get it to, let's say 500mV?; the heatsinks seem to allow for a higher bias).
