Back in post 2054, I had broken a drill bit in the hole for the 1/4" headphone jack. Thought I would just buy a new front. Instead enlarged the hole to about 50mm, which removed the broken drill bit hole and added a 4mm piece of brass to the mount the jack. Problem solved.
Now to enjoy!!
Now to enjoy!!
Attachments
For on ear type I have kept two old models. Grado SR60 and Sennheiser HD40. Mainly to can test 32 Ohm and 600 Ohm loading because I don't like the feeling of headphones sitting on the ear for too long. They usually don't achieve a wide image too compared to over ear ones. When it comes to travel the on ear type is small and light though, very adequate. Remember the massively popular Koss Portasound of yore? Still in production for those reasons and a good balance on the cheap. The Thinksound looks much more advanced and well made though. At Massdrop price a bargain. Although Massdrop's best bargain in absolute terms should have been their HD6xx runs (custom color Sennheiser HD650).
I like that
Got a DT 150 for my collection meantime. Has fleshy tone, has clarity, has definition, has depth, has defined instruments positions. Does not push back the vocals like many closed back cans unfortunately do, and it has sufficient stage size while many closed backs don't. Does bass but does not do much sub bass, has great HF extension but not super fine treble texture. Does not have modern looks, has vintage pro looks. Has roomy pads and light weight. Its built to last and to easily service. Made in Germany.
The cable is detachable with a proprietary flat connector. The right channel phone has six female pins and it attaches there. There's a metal threaded insert on the cup for securing the connector with a provided screw through an eyelet on it. The three meter cable ends in a mini jack with a quarter inch jack screw on adapter.
Two of the pins should be for an optional microphone because they showed nothing on the DMM but the remaining four pins on the cup showed separate ground return connections between drivers in the continuity rest.
A unique looking and sounding phone in the mid-low price closed back category. Excellent value IMO.
Attachments
Hi Salas, you recommend two 50VA transformers, at 18V sec. That's more than 1.389A (Serie) per transfo (Amgis No. L01-6384 from Digikey), per channel (in dual mono supply mode). Isn't overkill?
I would had expect this rating to be sufficien for both channel, and to use instead two transformer Avmeco TE70064, 36V, 25VA each, 0.694A (Serie) per channel, or the first 50VA model is the right one?
I have both in stock, and I want to be sure to select the correct one. Thanks
SB
I would had expect this rating to be sufficien for both channel, and to use instead two transformer Avmeco TE70064, 36V, 25VA each, 0.694A (Serie) per channel, or the first 50VA model is the right one?
I have both in stock, and I want to be sure to select the correct one. Thanks
SB
I had used 30VA split bobbin encapsulated trafos and they went near 45C hence the 50VA recommendation. Don't know if your encapsulated toroids run cooler.
Also in full bridge the trafos have 40% less max current. The preamp as a whole pulls 20W from the wall when at 100mA bias.
Keeping in mind the above info to decide your VA. Or do a dummy load test including bridge rectification and filter caps to check temperature on the small ones.
Also in full bridge the trafos have 40% less max current. The preamp as a whole pulls 20W from the wall when at 100mA bias.
Keeping in mind the above info to decide your VA. Or do a dummy load test including bridge rectification and filter caps to check temperature on the small ones.
Good news. Congrats. Post some pics also when you are able.
I ran the output voltage gamut for spot frequency THD reliable tests up to 5.66V pk-pk when the proto was finished. That is my USB audio box's 0dBFS max input. I checked that the sims followed too. High swing THD I ran only indicatively when it was on the breadboard via a divider. Full swing I had run on the scope that takes huge signal voltages just to see the waveforms shapes at max.
For the audio band THD sweeps I used voltage conditions like in the O2 tests. Half open pot noise is also involved. That amp had gone viral so there was a chance that more people would be familiar with such conditions I thought.
I also added sweeps with 32 Ohm to 600 Ohm real headphone loads, not only line level resistor loads. Those you see in post #1 are those charts I kept.
I can run a sim for you now though. You mean 5V pk-pk or RMS? Also at what output load?
I ran the output voltage gamut for spot frequency THD reliable tests up to 5.66V pk-pk when the proto was finished. That is my USB audio box's 0dBFS max input. I checked that the sims followed too. High swing THD I ran only indicatively when it was on the breadboard via a divider. Full swing I had run on the scope that takes huge signal voltages just to see the waveforms shapes at max.
For the audio band THD sweeps I used voltage conditions like in the O2 tests. Half open pot noise is also involved. That amp had gone viral so there was a chance that more people would be familiar with such conditions I thought.
I also added sweeps with 32 Ohm to 600 Ohm real headphone loads, not only line level resistor loads. Those you see in post #1 are those charts I kept.
I can run a sim for you now though. You mean 5V pk-pk or RMS? Also at what output load?
Was planning to just plug it for a quick test before making things clean, but can't turn off since
They work well together then. No weird surprises on first test = best possible news.
Here's your sim result. THD for 1kHz signal at 14dBV (5VRMS) output level. 100k load + 100pF for the interconnect.
Attachments
