I will try to get 9620. My DMM can't measure more than 1A, else it will burn. I think I will follow spec of 1.5A. That is what I am thinking of 0.8ohm for R301.
I use these for BJT 3.3V setup, I hope it is useful:
-Cx04 4.7uF, 63V MKS4C044704D00KSSD Wima
-Cx02 220UF, 50V EEUFM1H221 PANASONIC
-Cx05 4700UF, 63V LLS1J472MELB NICHICON
-Rx05 500ohm trimmer
-Rx03 110ohm resister
-Dx02-x03 3xLEDs, x04 jumper
-Dx06 1xLED, x05 jumper
-D101 jumper
-Rx01 10ohm, voltage across 1.31v, target CCS current 131mA
-Dx21-24, 1N5399-E3/54 VISHAY
-toroidal trans 75VA with 6.3Vac secondary
The rest is in the supply bag from GB.
Yup, it is my observation with SSLV1.1 BiB when powering my Class D t-amp 2024. I hope I have a scope to see more details but can't afford one at the moment.
Don't use the ammeter setting for measuring currents.
Instead insert a known resistor value into the circuit and set the DMM to voltmeter. Read off the volts drop across the resistor and you have the current passing into/through your circuit.
For peak currents approaching 1.5A use a resistor of <=0r1.
0r1 will give a reading of 150.0mVdc when 1.5Adc passes.
A good accuracy 0r1 can be assembled from 10off 1r0 1% resistors connected in parallel. I use 600mW for a Pmax=6W and this 10 resistor assembly runs cool enough to measure 4Apk (400mVpk Vdrop).
A poor accuracy 0r1 can be a 2W wirewound 5% or 10% "off the shelf" resistor.
When you get your oscilloscope. This monitoring of resistor Vdrop becomes your standard method for investigating signals/interference/hum in your circuits.
I now finished the second pos/neg 30V SSLV for the other channel. Parts compliment was the same as the other, but
Mosfets were sourced from different places. It works as good as the other, only now I cannot achieve my desired 30V.
Pos bottoms out on the trimmer at 29V, neg at 22V.
I take it from the previous comments that instead of putting in 3.4k (6.8k in //) I now have to go higher, say 10k?
Will be a bit more of a PITA since soldering in very tight spaces...
coolhead, can you post here or PM me your 3.3v parts used. I want to put that into blog.
Are you gathering data for something?
Chris
Replaced IRF9610 with IRF9620, and changed r301 from 1ohm to 0.82ohm. Voltage across it during cold is 1.02v and 1.12v after warmup, that will be about 1.3A. Output set at 13.8v during cold and 13.7 after warmup.
Now there is no more slagging power the t-amp in my main system until the volume is very high. The initial impression is: background is very quite, separation is much better, can pin point the singer and instrument easily and bass is stronger.
Bad thing is the heat generated is tremendous, with my big block of aluminum, it is just nice to keep it under 50deg. The temperature measure at the point near the q306 is 47deg cel. the diodes is very very hot also, I also put small heat sink to it but I can't touch it for more than 1 sec after turn on for 30min. I think can use with bigger heat sink.
Overall I am quite impress with the result, next thing to do maybe is to add a fan for it. After that just sit back and enjoy.
Now there is no more slagging power the t-amp in my main system until the volume is very high. The initial impression is: background is very quite, separation is much better, can pin point the singer and instrument easily and bass is stronger.
Bad thing is the heat generated is tremendous, with my big block of aluminum, it is just nice to keep it under 50deg. The temperature measure at the point near the q306 is 47deg cel. the diodes is very very hot also, I also put small heat sink to it but I can't touch it for more than 1 sec after turn on for 30min. I think can use with bigger heat sink.
Overall I am quite impress with the result, next thing to do maybe is to add a fan for it. After that just sit back and enjoy.
Last edited:
Despite the heat problem if you are willing to fight it with big sinks and accept the expense of energy, I had very good impression feedback on T-Amp from others too. Very first user with V1.0 and no remote, described 300B Amp traits from his T-Amp and SSL combo. I found it a bit weird. Does it remind DHT at all to your perception?
What is DHT? I personally prefer this small T-amp over the bigger brother. Thanks for the good invention, it is really nice, the PCB is very hardy, I do multiple solder and desolder, still in 1 piece. Great job. I going to order more.
I finally put mine together but can't adjust to my target of 12volts (at about 200ma).The negative reg won't adjust and hovers around 9.9 volts and the positive reg only has an adjustment range of 9.5 to 11.2.
I'm using the BJT version with a 1.8k resistor(R103,203) and A 2k2 pot in the voltage adjustment section with 2 x red LED's.I'm using a 50 ohm load resistor.
Would it be as simple as changing the value R103,203 to get greater adjustment range?
Thanks.
I'm using the BJT version with a 1.8k resistor(R103,203) and A 2k2 pot in the voltage adjustment section with 2 x red LED's.I'm using a 50 ohm load resistor.
Would it be as simple as changing the value R103,203 to get greater adjustment range?
Thanks.
5R6 and 3 green LED's. My circuit's current requirements are in the 70-80ma approx.
They now work like a charm loaded with the 100 ohm as you suggested.
Thank you kindly sir for the quick response.