@TungstenAudio,
I noticed you have used ceramic X7R and MKS type caps for C3,4,6,7 locations in the Diamond Buffer verification builds. Would the X7R be the preferred choice? Or whatever is in the parts bin 😉.
Thanks.
I noticed you have used ceramic X7R and MKS type caps for C3,4,6,7 locations in the Diamond Buffer verification builds. Would the X7R be the preferred choice? Or whatever is in the parts bin 😉.
Thanks.
I have ordered the X7R 2.2uF caps for these as TA listed in his mini parts list for the Diamond Buffer version in post #48.
The boards I’m currently playing have ceramic caps bypassing the voltage references and MKS caps bypassing the local power rails. Seems to be a good combo.
The IXTQ75N10 Mosfets have broken in over a few days. Presentation has smoothed out and is very enjoyable. Spinning some vinyl for the first time in a while; the F6 has developed some of the better aspects of a fine tube amplifier.
The IXTQ75N10 Mosfets have broken in over a few days. Presentation has smoothed out and is very enjoyable. Spinning some vinyl for the first time in a while; the F6 has developed some of the better aspects of a fine tube amplifier.
I did not have any caps that value and size, so ordered the one's as listed by TA.
Your listening impressions TA, are very encouraging.
Your listening impressions TA, are very encouraging.
Another question TA,
My F6 will be stuffed with FQH44N10’s and approximately +/-30V rails. I should use the lower value of 68R for R11, R12 as you mentioned in post#3?
(Also will mimic your R1//R1* combo.)
My F6 will be stuffed with FQH44N10’s and approximately +/-30V rails. I should use the lower value of 68R for R11, R12 as you mentioned in post#3?
(Also will mimic your R1//R1* combo.)
What are you going to use Vunce for the second R1 value which TA has shown as 0.0909ohms? Looks like it might be 0.47R in series with 0.1R nearest value.
68R seems to be a good value for the gate stopper resistors.
R7 and R8 can be bumped to 3.6k if you want to limit current through the green LEDs.
R7 and R8 can be bumped to 3.6k if you want to limit current through the green LEDs.
Do we ever take the easy way Gary? 
Ok, 68R for gate stoppers
I was prepping to use 3K for R7 and R8, did you find this value was too much current through the LED's?
Then I'll shift to 3K6.
LTL2R3KGD is the part number of the LED's I will use, they have the same forward voltage (1.96v) as the LTL-4231N's that were tested.
Thanks TA!
Ok, 68R for gate stoppers
I was prepping to use 3K for R7 and R8, did you find this value was too much current through the LED's?
Then I'll shift to 3K6.
LTL2R3KGD is the part number of the LED's I will use, they have the same forward voltage (1.96v) as the LTL-4231N's that were tested.
Thanks TA!
For 30V rails, shift to 3.6k. I‘m using 3.3k with 26.5V rails.
LEDs will regulate well around 5 mA or a little higher.
LEDs will regulate well around 5 mA or a little higher.
I know NN and PP will match well, but it depends on the batches in the parts bin how close N to P will be.
I haven’t matched any of my transistors. Just using cut tape lots. I wanted to test configurations that are easy to build.
We do this for entertainment, so match away if you like. Hand made amplifiers are special.
We do this for entertainment, so match away if you like. Hand made amplifiers are special.
I have about 50 of each transistor, so might see how close they match this afternoon here. Also good to know you just threw in the transistors as you picked them up TA. I have the time so will see how close I can match.
OK, I have checked the matching on the KSA992FBU and KSC1845FTA transistors I have here.
For the KSA type, the min Hfe was 462 and max was 520. For the KSC type, the min Hfe was 408 and max was 456.
Out of all that, I got 462 & 466 for KSA and 456 & 456 for KSC for one channel - that is 2.3% match. For the other channel I got 467 & 469 for KSA and 455 & 455 for KSC - that is 3.1% match.
While I was at it, I also checked the Toshiba TTC004B and TTA004B
For the TTC type, the min Hfe was 175 and max was 245. For the TTA type, the min Hfe was 183 and max was 247.
For the left channel I picked TTC at 221 and TTA at 221 - perfect Hfe match.
For the right channel I picked TTC at 222 and TTA at 225 - 1.4% match.
Let's see how Vunce goes with his matching, for all types tested it was easy to get multiple pairs prefectly matched N to N and P to P. It is the N to P matching that is hard to get perfect. I tested about 50 of each of the 4 transistor types using a Peak DCA75 pro tester.
For the KSA type, the min Hfe was 462 and max was 520. For the KSC type, the min Hfe was 408 and max was 456.
Out of all that, I got 462 & 466 for KSA and 456 & 456 for KSC for one channel - that is 2.3% match. For the other channel I got 467 & 469 for KSA and 455 & 455 for KSC - that is 3.1% match.
While I was at it, I also checked the Toshiba TTC004B and TTA004B
For the TTC type, the min Hfe was 175 and max was 245. For the TTA type, the min Hfe was 183 and max was 247.
For the left channel I picked TTC at 221 and TTA at 221 - perfect Hfe match.
For the right channel I picked TTC at 222 and TTA at 225 - 1.4% match.
Let's see how Vunce goes with his matching, for all types tested it was easy to get multiple pairs prefectly matched N to N and P to P. It is the N to P matching that is hard to get perfect. I tested about 50 of each of the 4 transistor types using a Peak DCA75 pro tester.