Those new boards look real nice....... adding the trim pot is a nice addition....I think I would like to use them for another amp using the higher voltage OP devices and a new PS for 24vdc. For lowest possible distortion with low Z headphones.
BTW - is anyone having a hard time matching the input jfets? I ordered a lot of them at eBay and all the ones I could get seemed to have the Id I speced/test for missing !?
Original ones were new from USA distributor (Fairchild) and I could find plenty in a small batch.
THx-Richard
BTW - is anyone having a hard time matching the input jfets? I ordered a lot of them at eBay and all the ones I could get seemed to have the Id I speced/test for missing !?
Original ones were new from USA distributor (Fairchild) and I could find plenty in a small batch.
THx-Richard
using all original transistors or ?? ones? and what supply voltage are you using.
Have you tried +/-24vdc supply?
-Richard
Have you tried +/-24vdc supply?
-Richard
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> 0dBV into 250 ohms -- using a lab supply (not a super-regulated low noise supply):
How about a 50 ohm load ?
Patrick
How about a 50 ohm load ?
Patrick
Early in this forum... I gave my measured data for low Z but more recently, I have found the distortion is even lower into low Z loads when I use the +/- 24vdc supplies... which need the higher voltage output devices... although I did test it with originals to 24 v and nothing smoked. But wouldnt recommend other try it. I am going to the higher voltage supply and OPS then will give new numbers here.
THx-RNMarsh
THx-RNMarsh
THD into 50 Ohms -
using all original p/n and +/- 15vdc power supply -- Here is THD into 50 Ohms:
1v rms and 2v rms - no filters used:
THx-RNMarsh
using all original p/n and +/- 15vdc power supply -- Here is THD into 50 Ohms:
1v rms and 2v rms - no filters used:
THx-RNMarsh
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So Richard, how much more do you want? 🙂 I do enjoy the amp with the dual power supplies. Open, dynamic, fluid in a natural way, transparent and layered. Hey, sounds good to me. I did add some caps right after the PS's, then on to the board. I also used some Black Gate non polar for bypass. Love those BG's.
They are just some simple sealed units from Jameco. I will have to look at their number. Everything fits in one case. Normally I like a PS with umbilical and mess with it until I get what I like but in this case I just wanted to get everything done. With the caps that follow it there is a nice reserve and the DC is clean. I first built it with one PS and because I like either dual or what I call pseudo dual PS, I put in the second and noticed a more open, dynamic and layered presentation.
I wish I had more gain at times.
I am listening with the new HiFiman HE1000. They are compared to some of the finest headphones currently made and in some respects, better than the R10 and more open sounding.
Has anyone done a balanced amp with these boards? 2 boards and 4 power supplies and up the voltage and components to 24 volts. I am glad I put the Goldpoint volume control in. Better made than the DACT, which just copies what Goldpoint does. I also used my high purity dead soft silver for all wiring except some of the power supply connections.
I am listening with the new HiFiman HE1000. They are compared to some of the finest headphones currently made and in some respects, better than the R10 and more open sounding.
Has anyone done a balanced amp with these boards? 2 boards and 4 power supplies and up the voltage and components to 24 volts. I am glad I put the Goldpoint volume control in. Better made than the DACT, which just copies what Goldpoint does. I also used my high purity dead soft silver for all wiring except some of the power supply connections.
Ok, great thanks.
This little amp is able to work well with these ortho headphones. I have the beta tester but it is most likely the final version. Great stuff!
Hifiman, out of China. They have made orthos for a few years now with the HE-6 considered top headphones but requiring a lot of power. These are much easier to drive and are even better sounding and are being compared to the best in the world and are possibly the best of all current headphones. They will retail for 3,000.00$ They are also much lighter than many ortho phones. The transducer material on these is so light that it almost floats on the air but yet very strong. They have the speed of an electrostatic but with a much deeper and solid and articulated bass foundation.
The DIY amp does great with them and this phone is so transparent that it changes with whatever you are driving it with so what you use, needs to be good.
Yes the T50RP scales quite well. The HE1000 is on a different planet. I have the Fostex TH0900, which are some great headphones but I have heard nothing, including the Sony R10, to compare to the HE1000.