Hi,
I am collecting parts to build SIT-Singing Bush.
Please advice me about the transformer.
I will custom order the R-core transformer.
So, I can select output voltage and current. I will order two identical transformers, since it is for monoblock.
In my plan, the outputs of the transformer are AC46v / 6A (276VA) and AC15V / 0.1A.
Please advise if it`s better to add tap or separate winding for future improvement/fun etc.
In addition, I plan to build amp with THF51S first and then replace it with 2SK77B.
Thank you. Stay safe.
I am collecting parts to build SIT-Singing Bush.
Please advice me about the transformer.
I will custom order the R-core transformer.
So, I can select output voltage and current. I will order two identical transformers, since it is for monoblock.
In my plan, the outputs of the transformer are AC46v / 6A (276VA) and AC15V / 0.1A.
Please advise if it`s better to add tap or separate winding for future improvement/fun etc.
In addition, I plan to build amp with THF51S first and then replace it with 2SK77B.
Thank you. Stay safe.
Attachments
if you shoot for 60 to 65Vdc , that calls for 48Vac to 52Vac xformer secondary
say that 276VA is absolute minimum I would use
46Vac seems sorta on low side, but it is doable, shaving a little from max possible swing, thus power; if you're ordering custom xformer (as I understood), ask for these few volts more
additional 15Vac/100mA winding is absolutely OK, there is no need for separate xformer
say that 276VA is absolute minimum I would use
46Vac seems sorta on low side, but it is doable, shaving a little from max possible swing, thus power; if you're ordering custom xformer (as I understood), ask for these few volts more
additional 15Vac/100mA winding is absolutely OK, there is no need for separate xformer
Haha. Attached is the 350VA size R-Core transformer that I used for my F4.
Is it small? Not enough?
OK, I will consider a 500VA size core.
(Although 1000VA is possible ...)
I order to Phoenix Corporation in Japan. They accept custom orders from amateurs.
However, I do not know about order from overseas.
Is it small? Not enough?
OK, I will consider a 500VA size core.
(Although 1000VA is possible ...)
I order to Phoenix Corporation in Japan. They accept custom orders from amateurs.
However, I do not know about order from overseas.
Attachments
It is interesting to see what a 350VA size R-core looks like. For building an amp like the Singing Bush, the 500VA size would be a good choice for building a pair of monoblocks.
I am still waiting for my boards, and I am saving a pair of 625VA, 50V Plitron toroid transformers for this build.
I am still waiting for my boards, and I am saving a pair of 625VA, 50V Plitron toroid transformers for this build.
I went "nothing is overkill" with 600VA 50V Antek 6450 transformers in my BAF2015 THF-51S monoblocks. With a CLC of 44mF - Hammond 159ZJ (10mH 0.16R) - 44mF, the output under load was around 62.5VDC. The amps are quiet with my 103dB speakers.
Recently I changed from 0.5R between current source and THF (Iq=2.55A) to the ZM prescribed 0.6R (Iq=2.1A). This lowered the harmonic distortion some more and is better sounding to my ears. Thanks, ZM.
Recently I changed from 0.5R between current source and THF (Iq=2.55A) to the ZM prescribed 0.6R (Iq=2.1A). This lowered the harmonic distortion some more and is better sounding to my ears. Thanks, ZM.
RESISTOR TYPE PACK SOT227
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I went "nothing is overkill" with 600VA 50V Antek 6450 transformers in my BAF2015 THF-51S monoblocks. With a CLC of 44mF - Hammond 159ZJ (10mH 0.16R) - 44mF, the output under load was around 62.5VDC. The amps are quiet with my 103dB speakers.
Recently I changed from 0.5R between current source and THF (Iq=2.55A) to the ZM prescribed 0.6R (Iq=2.1A). This lowered the harmonic distortion some more and is better sounding to my ears. Thanks, ZM.
Hi Ben,
Can you post some pictures of you mono-block build. I'm midway through a De-Lite build and I'm already plotting my next build Singing Bush Monoblocks!
Jeffrey
Hi Jeffrey,
I built them last fall, before ZM started the Singing Bush work.
My first post was:50w Single-Ended BAF2015 Schade Enabled
First pictures:50w Single-Ended BAF2015 Schade Enabled
More:50w Single-Ended BAF2015 Schade Enabled
I have tweaked them as mentioned, so now they are running at ZM's derived operating point. I have a few posts in this thread also.
I built them last fall, before ZM started the Singing Bush work.
My first post was:50w Single-Ended BAF2015 Schade Enabled
First pictures:50w Single-Ended BAF2015 Schade Enabled
More:50w Single-Ended BAF2015 Schade Enabled
I have tweaked them as mentioned, so now they are running at ZM's derived operating point. I have a few posts in this thread also.
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Thanks Ben
Your build is great! Do you have to use the fans much? I'd like to have all passive cooling but I fear that I may end up with dinosaurs for amps. I read through some of your comments about how it sounds and now I am more excited than ever to build. What are you driving your amps with?
Jeffrey
Your build is great! Do you have to use the fans much? I'd like to have all passive cooling but I fear that I may end up with dinosaurs for amps. I read through some of your comments about how it sounds and now I am more excited than ever to build. What are you driving your amps with?
Jeffrey
When I was running the amps at the original 3.2A, I needed to run the fans. The amps were dissipating about 200W per channel Now that they are running at 2.1A, I can probably run them fanless.
Note the close spacing of the heatsink fins. They were designed for use with fans. I was prepared for a lot of heat dissipation.
So if you choose regular fanless heatsinks, then no problems, unless the heatsinks are too small. Dissipation required is approximately 60V x 2.1A = 126W per channel, or maybe a bit higher, depending on your final power supply voltage. My power supply using a 50VAC transformer ended up outputting 62.5VDC under load. If you do monoblocks with two heatsinks per monoblock, with the SIT on one heatsink and the IXFN on the other, then the SIT heatsink would only need to dissipate about 75W, and the IXFN less.
I am driving the amps with a Luminaria preamp. Its output impedance is about 70 ohm, so no input buffer is needed for the amp.
Note the close spacing of the heatsink fins. They were designed for use with fans. I was prepared for a lot of heat dissipation.
So if you choose regular fanless heatsinks, then no problems, unless the heatsinks are too small. Dissipation required is approximately 60V x 2.1A = 126W per channel, or maybe a bit higher, depending on your final power supply voltage. My power supply using a 50VAC transformer ended up outputting 62.5VDC under load. If you do monoblocks with two heatsinks per monoblock, with the SIT on one heatsink and the IXFN on the other, then the SIT heatsink would only need to dissipate about 75W, and the IXFN less.
I am driving the amps with a Luminaria preamp. Its output impedance is about 70 ohm, so no input buffer is needed for the amp.
I have been curious about this too. The scant hierarchies place it Burning Bush a bit above SissySit, perhaps because of single ended and power heft, but close.
https://www.diyaudio.com/forums/pas...le-baf2015-schade-enabled-91.html#post5958520
I will be glad when more opinions come in. The Burning Bush looks to be more of a beast with its much larger chassis, power supply and heat sinks, so maybe it is down to power requirements.
https://www.diyaudio.com/forums/pas...le-baf2015-schade-enabled-91.html#post5958520
I will be glad when more opinions come in. The Burning Bush looks to be more of a beast with its much larger chassis, power supply and heat sinks, so maybe it is down to power requirements.