To3 and similar metal encased devices rated to 200degC can be operated at those sort of temperatures on the sink or on the case.
Plastic packaged devices rated to 150degC will probably not stay in spec for long at these elevated sink and case temperatures.
The derating factors for 150degC & 200degC devices is shown below.
Tc . . . . 100degC . . 110degC . . 120degC
To3 . . . . 0.57 . . . . . . 0.51 . . . . . 0.46
To264. . . 0.4 . . . . . . 0.32 . . . . . 0.24
BTW,
the temperature on top of the case will be different from the Tc measured at the interface with the heatsink.
Plastic packaged devices rated to 150degC will probably not stay in spec for long at these elevated sink and case temperatures.
The derating factors for 150degC & 200degC devices is shown below.
Tc . . . . 100degC . . 110degC . . 120degC
To3 . . . . 0.57 . . . . . . 0.51 . . . . . 0.46
To264. . . 0.4 . . . . . . 0.32 . . . . . 0.24
BTW,
the temperature on top of the case will be different from the Tc measured at the interface with the heatsink.
F5 Oscillating Need Help!
Hi,
I just finished the F5. without any input or speakers connected, I was able to adjust the bias between 0-10mV. It takes a good while for it to warm up before proper adjustment.
I am using a Speaker Protector Circuit. It kicks in at about 1V.
I thought everything was dandy so I hooked up my aikido pre and turned everything on. I got intermittent pops. good thing I used the speaker protector.
I disconnected the speakers and tried again. When I turn on the aikido, it seems to OSCILLATE. It jumps anywhere between -5 to 20VDC! Akido off, it's steady.
I've run the aikido with the mini-A and my ref C without
any issues. exact same setup, ac cables,etc..
these are Peter Daniel's boards.
RCA inputs are isolated from chassis.
1. Aleph PSU +V and -V going to F5 boards
2. Aleph PSU Ground going to chassis and earth gnd through .1uF||10 1W Res
3. Aleph PSU Ground going to - Speaker Terminals
thanks.
Hi,
I just finished the F5. without any input or speakers connected, I was able to adjust the bias between 0-10mV. It takes a good while for it to warm up before proper adjustment.
I am using a Speaker Protector Circuit. It kicks in at about 1V.
I thought everything was dandy so I hooked up my aikido pre and turned everything on. I got intermittent pops. good thing I used the speaker protector.
I disconnected the speakers and tried again. When I turn on the aikido, it seems to OSCILLATE. It jumps anywhere between -5 to 20VDC! Akido off, it's steady.
I've run the aikido with the mini-A and my ref C without
any issues. exact same setup, ac cables,etc..
these are Peter Daniel's boards.
RCA inputs are isolated from chassis.
1. Aleph PSU +V and -V going to F5 boards
2. Aleph PSU Ground going to chassis and earth gnd through .1uF||10 1W Res
3. Aleph PSU Ground going to - Speaker Terminals
thanks.
Attachments
Re: F5 Oscillating Need Help!
1. Check if there is any DC voltage leaking on the Aikido output.
2. Replace the cables from in RCA connectors to PCB on your F5 with shielded ones.
3. Check the reaction of the F5 in several steps:
a. without interconnects attached to the amp box
b. with only one interconnect cable
c. with both interconnects attached
d. Aikido turned off, attached one, then, both channels
e. Aikido on, volume down, one interconnect, then, both channels.
I got a low level buzz from my F5 when connected to NS10 when the F5 and NS10 were connected and with experiment, found that with certain cheap interconnects, NS picks up crap on the way from the CD. By increasing the volume (no signal), the buzz grew, at zero volume setting on the NS10, there was just a slight buzz, only audible with my ear on the bass drivers. Without interconnects, the F5 was dead quiet. No protection circuitry in mine. By replacing the interconnects between F5 and NS10 & CD and NS10, displacing them to be further away from each other, all the interference disappeared...
So, I suggest that you play a bit with the with the wiring. Disconnect the speakers and measure (if you can - able to) what happens with the amp... Also, if nothing from above helps, try to omit the protection circuitry or dislocate it...
But first go the suggested way...
Bengali said:
1. Check if there is any DC voltage leaking on the Aikido output.
2. Replace the cables from in RCA connectors to PCB on your F5 with shielded ones.
3. Check the reaction of the F5 in several steps:
a. without interconnects attached to the amp box
b. with only one interconnect cable
c. with both interconnects attached
d. Aikido turned off, attached one, then, both channels
e. Aikido on, volume down, one interconnect, then, both channels.
I got a low level buzz from my F5 when connected to NS10 when the F5 and NS10 were connected and with experiment, found that with certain cheap interconnects, NS picks up crap on the way from the CD. By increasing the volume (no signal), the buzz grew, at zero volume setting on the NS10, there was just a slight buzz, only audible with my ear on the bass drivers. Without interconnects, the F5 was dead quiet. No protection circuitry in mine. By replacing the interconnects between F5 and NS10 & CD and NS10, displacing them to be further away from each other, all the interference disappeared...
So, I suggest that you play a bit with the with the wiring. Disconnect the speakers and measure (if you can - able to) what happens with the amp... Also, if nothing from above helps, try to omit the protection circuitry or dislocate it...
But first go the suggested way...
Attachments
hi,
im about to buy used 800W plitron tranny with good price.
the thing is, it have sec output 20V-0-20V.
are there any downside using CT trany instead of dual sec (2x20V) besides using 1 and 2 bridge rectifier?
second Q.
for filtering caps. better using 6x 15.000uf or 12x10.000uf ?
i have 6 RIFA PEH169 15.000uf and 12 panasonic 10.000uf cap in stock now.
thanks for the answer.
im about to buy used 800W plitron tranny with good price.
the thing is, it have sec output 20V-0-20V.
are there any downside using CT trany instead of dual sec (2x20V) besides using 1 and 2 bridge rectifier?
second Q.
for filtering caps. better using 6x 15.000uf or 12x10.000uf ?
i have 6 RIFA PEH169 15.000uf and 12 panasonic 10.000uf cap in stock now.
thanks for the answer.
Bengali said:
Thanks Stein2. coffee would have helped me as well
great troubleshooting steps!
The image attached is my F5. The input/output wires go quite near each other and the input wiring is made from UTP (PC networking) cable. At first I suspected that might be the problem in my case.
Once I took a better look into your attached image, it was oh_so_obvious that you lack one piece of wire per channel...
Glad it's all ok now, even though my posting wouldn't help at all!
audioholik said:
A 2 Q1: Not a problem, especially if it's well priced. 800VA is overkill in any case, enough for four channels.
A 2 Q2: Why not use all of them? I have filled up the box with filtering caps (16x33mF). Not a dramatic improvement, but does work better, especially when the load is demanding (4 Ohm electrostatics)
questions and reflections-f5/b-1
Good morning gentle readers;
Its been awhile since we've spoken and I thought I'd reach out this drizzly am. Coffee is in-hand of course.
I have been living with a B-1 and F5 for about a month now. The B-1, as compared to my reference db systems preamp from the late 70's, has a speed and rightness about it that is most satisfying. At some point I will catalog my impressions of their sonics ( the B-1 and the F5 that is) with references to specific music, but not today.
The F5 has been a little harder for me to embrace. My reference for comparison is a modded ST70(heathkit tube amp of aprox same power) and the sound is rather different. Not a bad thing but I would have a middle-ground. The tube amp has a fullness and richness to its presentation that the F5 does not. The F5 has a cleanliness and accuracy that the tube does not. Particularly on weaker recordings( read not audiophile , not SACD, not Waterlilly) the analytical nature of the F5 really highlights the thinness/tinniestnessmess(nice word eh?) of the source material. Obviously not a shortcoming of the amp, ie what goes in is what goes out, but there is such thing as voicing which is the art of balancing the sound of a particular component. I've been a speaker builder for decades and I'm sure you can appreciate this concept relative to speakers. I would assert the same goes for all electronics, no apologies to the Luddites that feel all amps sound the same!
Good morning gentle readers;
Its been awhile since we've spoken and I thought I'd reach out this drizzly am. Coffee is in-hand of course.
I have been living with a B-1 and F5 for about a month now. The B-1, as compared to my reference db systems preamp from the late 70's, has a speed and rightness about it that is most satisfying. At some point I will catalog my impressions of their sonics ( the B-1 and the F5 that is) with references to specific music, but not today.
The F5 has been a little harder for me to embrace. My reference for comparison is a modded ST70(heathkit tube amp of aprox same power) and the sound is rather different. Not a bad thing but I would have a middle-ground. The tube amp has a fullness and richness to its presentation that the F5 does not. The F5 has a cleanliness and accuracy that the tube does not. Particularly on weaker recordings( read not audiophile , not SACD, not Waterlilly) the analytical nature of the F5 really highlights the thinness/tinniestnessmess(nice word eh?) of the source material. Obviously not a shortcoming of the amp, ie what goes in is what goes out, but there is such thing as voicing which is the art of balancing the sound of a particular component. I've been a speaker builder for decades and I'm sure you can appreciate this concept relative to speakers. I would assert the same goes for all electronics, no apologies to the Luddites that feel all amps sound the same!
reflections and questions pt 2
Just froze-up- don't know if its me our the forum but back to the reflections and then a few questions.
I have about 50-60 hours on the amp and either it is getting a little warmer or my ears are just acclimating. (or perhaps bringing the bias up from .4 to .6vlts had this effect) I have subbed the ST70 back into the system on occasion and still support the afore stated comparrison of sound. One one occasion my 15 yr old walked into the room to appreciate "Little Wing" off Access Bold as Love and immediately commented that he liked the tube amp better. Having glowered at him till he ran from the room, I had to admitt that there was a certain pressence missing with the F5. This is not commdemnation, the F5 has many great qualities but some shortcomings too.
This is a tough comparison but I'm wondering if there is a way to bring a little more warmth (as NP once said from "a tad of 2nd harmonic warmth" to a bit more?)to the amp's presentation?
I've played with the bias with some improvement and was wondering if anyone who has removed the limiting network has heard any "warming-up"? (BTW when you remove Q5/R19/R17- Q6/R20/R18 wouldn't you need to jump R22 & R21 back up to the voltage rails?)
I'm assuming the thermistors are fairly innocuous and should help maintain bias settings. In speaking of this when I've set my bias I've noticed that I can set it to a range but not get it to stop a plus minus 5 millivolt movement. My inputs are not shorted and I do have a florescent light overhead. Anyone else have this "issue"?
I'm about to build my second set of PD boards with caddock resistors in positions R1&R2(10 ohm 15 watt) R5&R8(50 ohm 15 watt) and R11&R12(.5 ohm 30 watt)- I thought I saw someone mention that some of these should be heat-sunk. Yea or neigh? Which ones? I'm assuming the .5 ohm 30 watters but am not sure.
Hope all is well with "you-all" and any and all input is deeply appreciated
Have a good-un
rob
Just froze-up- don't know if its me our the forum but back to the reflections and then a few questions.
I have about 50-60 hours on the amp and either it is getting a little warmer or my ears are just acclimating. (or perhaps bringing the bias up from .4 to .6vlts had this effect) I have subbed the ST70 back into the system on occasion and still support the afore stated comparrison of sound. One one occasion my 15 yr old walked into the room to appreciate "Little Wing" off Access Bold as Love and immediately commented that he liked the tube amp better. Having glowered at him till he ran from the room, I had to admitt that there was a certain pressence missing with the F5. This is not commdemnation, the F5 has many great qualities but some shortcomings too.
This is a tough comparison but I'm wondering if there is a way to bring a little more warmth (as NP once said from "a tad of 2nd harmonic warmth" to a bit more?)to the amp's presentation?
I've played with the bias with some improvement and was wondering if anyone who has removed the limiting network has heard any "warming-up"? (BTW when you remove Q5/R19/R17- Q6/R20/R18 wouldn't you need to jump R22 & R21 back up to the voltage rails?)
I'm assuming the thermistors are fairly innocuous and should help maintain bias settings. In speaking of this when I've set my bias I've noticed that I can set it to a range but not get it to stop a plus minus 5 millivolt movement. My inputs are not shorted and I do have a florescent light overhead. Anyone else have this "issue"?
I'm about to build my second set of PD boards with caddock resistors in positions R1&R2(10 ohm 15 watt) R5&R8(50 ohm 15 watt) and R11&R12(.5 ohm 30 watt)- I thought I saw someone mention that some of these should be heat-sunk. Yea or neigh? Which ones? I'm assuming the .5 ohm 30 watters but am not sure.
Hope all is well with "you-all" and any and all input is deeply appreciated
Have a good-un
rob
Re: reflections and questions pt 2
--- some posts back, I think it was in this thread on the F5, NP states that using IR mosfets have more 2nd order HD, as opposed to the Fairchilds. Which are you running in your F5 build? The IRs might warm it up for you, I plan on trying this myself, won't be for awhile though, trying a balanced version will come first.
--- I too would like more comments on removing the 'limiting network' re: sound.
Just a thought, my
worth
---edit: oops NP posted while I was composing this ....
rob lenk said:
--- some posts back, I think it was in this thread on the F5, NP states that using IR mosfets have more 2nd order HD, as opposed to the Fairchilds. Which are you running in your F5 build? The IRs might warm it up for you, I plan on trying this myself, won't be for awhile though, trying a balanced version will come first.
--- I too would like more comments on removing the 'limiting network' re: sound.
Just a thought, my
worth---edit: oops NP posted while I was composing this ....
reflections and questions Pt3
I am running the IRDs having noticed NP's suggestion that these would be a little warmer-
NP, I'm late to DIY so I missed the baliwick about the F3- If you wouldn't mind what makes the F3 more "tubelike"?
I assume you have listened to an ST70 or two in your day, how do you hear the comparison tween F5 and "tube"?
Last question, am I correct in assuming you would need to tie in the voltage rail once you pull the limiting circuit?
thanks for your time
rob
I am running the IRDs having noticed NP's suggestion that these would be a little warmer-
NP, I'm late to DIY so I missed the baliwick about the F3- If you wouldn't mind what makes the F3 more "tubelike"?
I assume you have listened to an ST70 or two in your day, how do you hear the comparison tween F5 and "tube"?
Last question, am I correct in assuming you would need to tie in the voltage rail once you pull the limiting circuit?
thanks for your time
rob
Hi Rob,
My two cents, I built mine about 1 1/2 yrs ago. I never had any issue with the bias roaming more than a couple ma after warmup. I can't see needing any heatsinks on the Rs, 15 watters should be more than sufficient.
I have to agree with you about the sound being on the sterile side of clarity. I had thought about replacing most of the Rs with carbon film types but never got to it, and don't know if it would help or not. Pushing up the bias gets risky over 35W per fet, I wonder if paralleling another set of fets along with bigger heatsinks would be doable with the present front end. The unit has been relegated to the workshop system. It's not in the same league as my Aleph 5 clone.
I would also like to hear from other users.
Best, Bill
My two cents, I built mine about 1 1/2 yrs ago. I never had any issue with the bias roaming more than a couple ma after warmup. I can't see needing any heatsinks on the Rs, 15 watters should be more than sufficient.
I have to agree with you about the sound being on the sterile side of clarity. I had thought about replacing most of the Rs with carbon film types but never got to it, and don't know if it would help or not. Pushing up the bias gets risky over 35W per fet, I wonder if paralleling another set of fets along with bigger heatsinks would be doable with the present front end. The unit has been relegated to the workshop system. It's not in the same league as my Aleph 5 clone.
I would also like to hear from other users.
Best, Bill