So now there is silence when previously you said there was noise. Is there still AC voltage?
If you measured good voltages at T1 and T2, that is a good sign that the J113 is working.
If you input an AC signal, you can track its progress at the J113 gate, at the J113 drain, at the input and output of the output capacitor, at the RCA output jack, at the output end of the RCA interconnect. There are lots of clues to be found.
If you measured good voltages at T1 and T2, that is a good sign that the J113 is working.
If you input an AC signal, you can track its progress at the J113 gate, at the J113 drain, at the input and output of the output capacitor, at the RCA output jack, at the output end of the RCA interconnect. There are lots of clues to be found.
@Ben Mah My mistake, from this H2 I never got sound or noise out. I had another channel in parallel with H2 and input from signal generator then from one channel connected straight from signal generator to amp I can here that signal noise but the other channel that goes through H2 I do not hear any noise or sound. I think that i will give up and wait for H2 PCB-s from DIYaudiostore with right J113-s and then we will see if that is working with my set up. Shipment from US to EU may take quite a long time.
I finished my 2nd H2 today, or so I thought. I only had 100R 25 turn pots and put 40somethingR in R6, but could not get to desired voltage at T2. Reduced R6 and could set voltage to specified 10V85.
I did not have much time, and being the 2nd easy build did not measure anything else.
I then hooked it up to my Aleph J testamp, fed it some music through a squeezebox classic and had sound, but quality was not great. As a reference I took the H2 out (i.e. hooked up the squeezebox to Aleph J direct), and the aound quality was much better.
When something goes wrong, the gods get together to make sure everything goes wrong. So, I blew the fuses in my Aleph J when I switched it on again between tests (probably drew too much current because ntc had not cooled down fully), only had one channel workin which we found to be due to pulling out one speaker wire when turning the amp to replace the fuses, etc. You get the picture. When it was finally connected again with the H2 in circuit, I only got white noise. Turns out the old wall wart had died. None of the other 12V wall warts I had lying around fitted the (what I assumed was a standard) barrel plug, so I will need to change the connector and try again.
My helper had to leave, so we had no time for detailed measurements.
That's it for today, but I will get back to it in a few days when my helper is back.
The reason I mention this, is that @viltsone mentioned noise issues. In my case I suspect a failing wall wart was the issue (I'll find out in a few days, I hope), but for viltsone perhaps an idea to check your power supply or try your own board using a trusted stable power source, e.g. bench power supply.
Worth noting perhaps:
I ran out of the nice 1000uF capacitors I had used in my previous build, and used 1800uF 35V UCC GPD instead. Possibly nearly doubling the capacitance overloaded my small wall wart.
I did not have much time, and being the 2nd easy build did not measure anything else.
I then hooked it up to my Aleph J testamp, fed it some music through a squeezebox classic and had sound, but quality was not great. As a reference I took the H2 out (i.e. hooked up the squeezebox to Aleph J direct), and the aound quality was much better.
When something goes wrong, the gods get together to make sure everything goes wrong. So, I blew the fuses in my Aleph J when I switched it on again between tests (probably drew too much current because ntc had not cooled down fully), only had one channel workin which we found to be due to pulling out one speaker wire when turning the amp to replace the fuses, etc. You get the picture. When it was finally connected again with the H2 in circuit, I only got white noise. Turns out the old wall wart had died. None of the other 12V wall warts I had lying around fitted the (what I assumed was a standard) barrel plug, so I will need to change the connector and try again.
My helper had to leave, so we had no time for detailed measurements.
That's it for today, but I will get back to it in a few days when my helper is back.
The reason I mention this, is that @viltsone mentioned noise issues. In my case I suspect a failing wall wart was the issue (I'll find out in a few days, I hope), but for viltsone perhaps an idea to check your power supply or try your own board using a trusted stable power source, e.g. bench power supply.
Worth noting perhaps:
I ran out of the nice 1000uF capacitors I had used in my previous build, and used 1800uF 35V UCC GPD instead. Possibly nearly doubling the capacitance overloaded my small wall wart.
I have good news. H2 boards arrived from Diyaudiostore. I had same issue at first that no sound. Then using DM I somehow was touching this Stereo Connector 6.35 mm tip pin pushing it and I heard sound. This NTR-NYS216 connector did not gave any contact to my 6.3 mm amp input cable. I could not believed it. Then I changed this connector to better one with another type and now sound comes out. So my first board is also working and now I have some extra boards if anybody interested.
I think it must be me but the H2 v2 sound quality is not the highest? I have some questions also. If I swap at the H2 output already polarity then I get hum noise sound in the speakers. Why is that so? How to fix that? I can not swap speakers polarity because active built in amp speakers.
How to change resistor gain volume so, that I can input 2 V and get out 2 V? Unity gain do not work if I like to keep distortion 1% level or? Increasing voltage or changing R3 resistor value to something else? Adding at the H2 output another preamp?
If I like to use another JFET with ids 12,5mA then R3 value needs to be changed according to ids mA-s? Does it affects H2 distortion?
I have some questions also. If I swap at the H2 output already polarity then I get hum noise sound in the speakers. Why is that so? How to fix that? I can not swap speakers polarity because active built in amp speakers.How to change resistor gain volume so, that I can input 2 V and get out 2 V? Unity gain do not work if I like to keep distortion 1% level or? Increasing voltage or changing R3 resistor value to something else? Adding at the H2 output another preamp?
If I like to use another JFET with ids 12,5mA then R3 value needs to be changed according to ids mA-s? Does it affects H2 distortion?
A few months ago I tried a few different preamps in one (long) session, including the H2, BA3pre and a few Chinese clones (JC-2 and SL-1). In that system (Logitech transporter feeding preamp single ended and single ended to a DIY Vfet poweramp powering Avalon Studio Pro monitors) the H2 was the nicest one to listen to, after the BA3pre.
So, my conclusion was it sounds great.
I built another one and tried it in my shed using a Squeezebox 3 classic, diy Aleph J and old test speakers. I was not as impressed as I had been earlier. I would not be surprised if the difference is caused by the powersupply (5V USB using a 5V to 12V converter where before it was a 12V wallwart I had in my drawer) or the psu cap I used on the 2nd H2 board. I have been too busy to test further and have not tested both H2s in the same system.
Try it with a simple linear power supply (7812 or LM317) and see if you have a nice cap for the psu cap lying around to try out. If that significantly changes the sound, you know where you should concentrate on.
So, my conclusion was it sounds great.
I built another one and tried it in my shed using a Squeezebox 3 classic, diy Aleph J and old test speakers. I was not as impressed as I had been earlier. I would not be surprised if the difference is caused by the powersupply (5V USB using a 5V to 12V converter where before it was a 12V wallwart I had in my drawer) or the psu cap I used on the 2nd H2 board. I have been too busy to test further and have not tested both H2s in the same system.
Try it with a simple linear power supply (7812 or LM317) and see if you have a nice cap for the psu cap lying around to try out. If that significantly changes the sound, you know where you should concentrate on.
I am using toroidal transformer with Super Regulator as voltage input. In my H2 board I use Panasonic FR 1000uF cap. For the output cap I have tried bi-polar Panasonic, electrolytic cap from Panasonic, Murata MLCC cap, Panasonic film cap. So far electrolytic and Bi-polar caps are out. Maybe they need to have some burn in time but they do not sound good at first.
I have also tried JFE2140 instead of J113 and sound difference is for me like a day and night. Next I will like to try Toshiba 2SK209-GR, JFE150 and LSK170B.
Any good finding what caps sounds good what to use?
I have also tried JFE2140 instead of J113 and sound difference is for me like a day and night. Next I will like to try Toshiba 2SK209-GR, JFE150 and LSK170B.
Any good finding what caps sounds good what to use?
Thanks, I gathered that, but I'm unclear about the meaning of "But never compared to a elyt version." In particular the words: "But never compared to". Do you perhaps mean that you haven't tried electrolytic caps? Or perhaps "elyt" means elite?
Sorry, I'm not meaning to be condescending at all. I really appreciate you sharing in English. It's also not my first language, by the way.
out of desperation, I ordered a V1 assembled board from Thailand - hope it works well - -I'm getting too crippled to do much of anything with head-forwards - shoulders frozen for over 20 years and trigeminal pain - plus broke as income = 0.6 outgo.
Once I have the means to ship I'll list 5842q tubes, HF87 and other stuff for sale. If anyone has an H2 for sale that works and ready to go - let me know.
Once I have the means to ship I'll list 5842q tubes, HF87 and other stuff for sale. If anyone has an H2 for sale that works and ready to go - let me know.
