JC951t said:
IMHO metal film resistors are essential for clarity and resolution. But why not mix them with carbon resistors? 1 or 2 Riken per channel will possibly do a good job.
For my F5 construction I'm thinking about to make it optional via switch or so.
Don't get me wrong, with excellent recordings the F5 is the best sounding little amp I know, but with poor or mediocre recordings (unfortunately the majority in pop and rock music) a little "flavor" may improve the pleasure.
> Can I use thermal past under the power mosfets or should I use something else?
If you would wish to use something more mordern and has higher performance :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=144076
Patrick
If you would wish to use something more mordern and has higher performance :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=144076
Patrick
Mica and goop indeed ,thats a good way to put it .
still the best in my book too.
Although I have been using "Arctic Silver" compound instead of the traditional white goop. You can find the silver stuff at most of the p.c. modding sites.
Above all be watchfull for debris on the parts that may cuse a penetration of the insulator, been there many times, life will not be pleasant if you don't take the time here.
still the best in my book too.
Although I have been using "Arctic Silver" compound instead of the traditional white goop. You can find the silver stuff at most of the p.c. modding sites.
Above all be watchfull for debris on the parts that may cuse a penetration of the insulator, been there many times, life will not be pleasant if you don't take the time here.
Mica thickness recomendation.
I'm going to order some Mica sheets from McMaster Supply Company and was wondering if someone could recomend a proper thickness. There selection is :.004",.008",.012",.016",.020" and .024" thickness. Nelson, what thickness do you use in the First Watt models?
Thanks,
Mark
I'm going to order some Mica sheets from McMaster Supply Company and was wondering if someone could recomend a proper thickness. There selection is :.004",.008",.012",.016",.020" and .024" thickness. Nelson, what thickness do you use in the First Watt models?
Thanks,
Mark
Hi,
It's taken me 4 months but I've finally read through this whole thread! Being of the caveman persuasion I thank N.Pass for this simple diy design. I had some problem with noise/buzz because of poor placement of components (transformer/input/output all grouped together on one side of amp) but slayed it with shielding of the transformer and cables.
Of all the photos of amps posted (many quite helpful) my favorite by far is Peter Daniels. Soldering the power cap right to the board. Never thought of that. And the input/outputs could only be shorter if one soldered the F/RCA and Speaker terminal post directly to the board (hmmm...).
A few questions:
1. Babowanna, previously you had questioned why removing the protection circuitry would improve things (I think AndrewT was the only one who gave a technical answer for why it might). Now that you have removed it do you think it has improved the sound or do you atribute any benefit to your regulated power supply?
2. P.Daniels (or anyone else), I am considering the 4-pole Jensens that you used. Any reason for these over, say, Mundorfs?
3. Stein2 has said removing the Resistor(s) from the CRC power supply improved things. It is my understanding that the R is to affect the ripple. Is there a consensus that removing this would improve things, or is it one of those things that it would improve in one area and have a neg effect in another? Part 2 of this question is that if I remove the R, is there any benefit to doing 4x15,000+ caps/channel (CC) vs 2x30,000+/channel (C)? I'm asking because it would be cheaper to do two larger caps vs four smaller ones.
4. Concerning bypass caps, ZenMod and Stein2 have advocated 50uf motor run caps. Those things look huge. Since I'm planning on putting the powersupply caps directly on the board ala P.Daniels, these things would need long leads. Also, does it make sense to combine a 4.7uf or .1uf or both with motor run caps?
Sorry for the long post and dredging up things from thousands of posts back. I sort of "regurgitated" all the questions I've been holding in these past few months.
It's taken me 4 months but I've finally read through this whole thread! Being of the caveman persuasion I thank N.Pass for this simple diy design. I had some problem with noise/buzz because of poor placement of components (transformer/input/output all grouped together on one side of amp) but slayed it with shielding of the transformer and cables.
Of all the photos of amps posted (many quite helpful) my favorite by far is Peter Daniels. Soldering the power cap right to the board. Never thought of that. And the input/outputs could only be shorter if one soldered the F/RCA and Speaker terminal post directly to the board (hmmm...).
A few questions:
1. Babowanna, previously you had questioned why removing the protection circuitry would improve things (I think AndrewT was the only one who gave a technical answer for why it might). Now that you have removed it do you think it has improved the sound or do you atribute any benefit to your regulated power supply?
2. P.Daniels (or anyone else), I am considering the 4-pole Jensens that you used. Any reason for these over, say, Mundorfs?
3. Stein2 has said removing the Resistor(s) from the CRC power supply improved things. It is my understanding that the R is to affect the ripple. Is there a consensus that removing this would improve things, or is it one of those things that it would improve in one area and have a neg effect in another? Part 2 of this question is that if I remove the R, is there any benefit to doing 4x15,000+ caps/channel (CC) vs 2x30,000+/channel (C)? I'm asking because it would be cheaper to do two larger caps vs four smaller ones.
4. Concerning bypass caps, ZenMod and Stein2 have advocated 50uf motor run caps. Those things look huge. Since I'm planning on putting the powersupply caps directly on the board ala P.Daniels, these things would need long leads. Also, does it make sense to combine a 4.7uf or .1uf or both with motor run caps?
Sorry for the long post and dredging up things from thousands of posts back. I sort of "regurgitated" all the questions I've been holding in these past few months.
Load Needed for Adjustment?
I am in the middle of constructing my F5, just reached the end of reading the 150 pages of the F5 thread, and have gone back to look at Nelson's F5 manual and the attached article. (all very wonderful to work one's way through!)
I have noticed something a little strange in the F5 article:
In the first two sentences of the second paragraph of the section on Initial Adjustment he states in an oddly phrased sentence that "Each channel does not need to be attached to a load in order to adjust it." But then he says that if the only load you have is a loadspeaker, he advises against using it - the implication being that some load is needed.
It is pretty clear from other posts that adjustment is taking place successfully without applying a load to the outputs.
I just wanted to check that I've got this right - no load needed.
[and of course no disrespect meant regarding Nelson's writing]
Thanks, Steve
I am in the middle of constructing my F5, just reached the end of reading the 150 pages of the F5 thread, and have gone back to look at Nelson's F5 manual and the attached article. (all very wonderful to work one's way through!)
I have noticed something a little strange in the F5 article:
In the first two sentences of the second paragraph of the section on Initial Adjustment he states in an oddly phrased sentence that "Each channel does not need to be attached to a load in order to adjust it." But then he says that if the only load you have is a loadspeaker, he advises against using it - the implication being that some load is needed.
It is pretty clear from other posts that adjustment is taking place successfully without applying a load to the outputs.
I just wanted to check that I've got this right - no load needed.
[and of course no disrespect meant regarding Nelson's writing]
Thanks, Steve
Hi,
do not connect any external load to the amplifier while testing and adjusting. You may/should experiment with different combinations of input conditions. This may reveal weird output voltages depending on switch on/DC coupling/input offset/volume setting etc.
When you are sure there is no damaging signal coming from the output, you can connect a resistor as a temporary load and complete your tests/checks.
Replace your resistor with a cheap speaker for final testing.
When you are ready to risk your expensive speakers, you should be sure you are not going to damage them.
do not connect any external load to the amplifier while testing and adjusting. You may/should experiment with different combinations of input conditions. This may reveal weird output voltages depending on switch on/DC coupling/input offset/volume setting etc.
When you are sure there is no damaging signal coming from the output, you can connect a resistor as a temporary load and complete your tests/checks.
Replace your resistor with a cheap speaker for final testing.
When you are ready to risk your expensive speakers, you should be sure you are not going to damage them.
alazira said:
Unfortunately, the beauty still remains in the eye of the beholder. I said before that I made my amps with a bit oversized filtering (8x33mF per channel - equaling 264mF pch) and a bit oversized heatsinks.
Leaving them 0.1R resistors in the PSU is the second simplest thing. Not putting them at all is even simpler, and I found that to be better, although not cheaper at the end because I already brought them home in a small nylon bag. And paid for them, of course
Building the same capacitance PSU from more smaller or less bigger caps might not have any audible or sufficient measurable difference that I could use as a pro or contra... I bought my 33mF/25V Panasonics in a group buy and it was the best offer at the time...
The motor Run caps are huge, but then, for the 25W you get, look at all the huge things you need to use... A huge transformer, huge heatsinks, huge filters, therefore a huge box... So, a couple of these is just icing on the cake...
Just take a look at the heatsinks used in Arcam's Alpha8 integrated amp... And that's 50W pch... (not Class A but probably the smallest heatsinks in any SS power amp......)
Hi Floyd 42,
I guess this is up to individuals taste. A mix & match is a good idea but at the same time you must consider the circuit as a whole. Meaning from transformers to filter caps to resistors etc.
In general lots of builders are into toroids with fast rect diodes
couple to low ESR filter caps. Using this as a basic formula & with
the inclusion of metal film resistors, the sound within my limited experience will definately be on the bright side. Frequency spectrum will be more towards the higher side & may sound
zinggy. Anyway everyones perception to sound reproduction
is very different. What I like may not be to your liking . Discussion of this nature is very subjective. I've built a couple of SS projects
including a few of Mr. Pass wonderful designs & I've arrived at this findings through lots of tweeking
I guess this is up to individuals taste. A mix & match is a good idea but at the same time you must consider the circuit as a whole. Meaning from transformers to filter caps to resistors etc.
In general lots of builders are into toroids with fast rect diodes
couple to low ESR filter caps. Using this as a basic formula & with
the inclusion of metal film resistors, the sound within my limited experience will definately be on the bright side. Frequency spectrum will be more towards the higher side & may sound
zinggy. Anyway everyones perception to sound reproduction
is very different. What I like may not be to your liking . Discussion of this nature is very subjective. I've built a couple of SS projects
including a few of Mr. Pass wonderful designs & I've arrived at this findings through lots of tweeking
Mica Insulators
Check out eBay: see - http://cgi.ebay.com/Mica-Insulators...QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported
Check out eBay: see - http://cgi.ebay.com/Mica-Insulators...QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported
Hi JC,
thanks for your answer. Sure it's up to individual taste, that supposedly is a mixture between preferences, habits, experiences but also physiological matters like the individual frequency response of our ears and the brain capacity reserved for audio perception (that may increase -> blind people) ...
I guess my point of view is not for away from yours. But let me explain. I believe that there are two hifi "religions", which have completely equal rights. I often use the terms Master-Hifi and Slave-Hifi.
Master-Hifi: The best music in the world is not very often preserved in the best recordings (for me e.g. The Beatles). We love this music and do everything to make it more enjoyable: Adding 2nd harmonics distortion to reconstruct real harmonics missing in the music (good luck!), warming up the sound (or give it more kick) using certain parts, varying the circuitry, using suitable concepts and so on... The resulting gear is in the best case breathtaking, seductive and loveable. (Yes, I have tube-amps in mind! But there are also solid states -DIY or not- like Naim, Phonosophie and First Watt F3 - Sorry Papa!)
For me these are the "sounding" devices. It's like a second mastering to the (imperfect) recording! But what's the difference!? Listen and enjoy!
Slave-Hifi: The term sounds minor but we'll see. "Clean Hifi" if you want. If it doesn't sound good, blame it on the recording (or the not finished burn-in-period)! An amplifier in this category tries not to sound. It's approximately neutral. Just amplifying the signal. Nothing is added, approximately (nice word ) nothing is taken. The perfect slave to the recording. A slave-amp is merciless to most recordings. But if the recording (and the rest of your gear) is excellent you'll reach the sky!!!
Ah, I forget to mention, that any other Hifi, that doesn't fit to one of these categories is for me NoFi.
For me the F5 is the perfect Slave-Amp: Ultra-low distortion, perfect linearity, no "sounding" capacitor in the signal path, only a few parts per channel. So I try to give it the "best" ("neutral") parts of the world market (I hope Michael Percy gets rich with these 12-Bucks-Resistors ) and get happy with it!
For me the F5 has only two disadvantages: It's limited power and my monthly electricity bill.
But of course you have every right in the world to transform the F5 into a Master-Hifi-Device, if you forgive me to use this term.
I don't want to do you wrong. I'm sure you have a huge experience in modifying and building amplifiers. If I have done you wrong take my excuse.
Greetings
Martin
P.S.: That Riken resistors are just an additional gimmick - a sort of Master-Hifi-Switch if you want.
thanks for your answer. Sure it's up to individual taste, that supposedly is a mixture between preferences, habits, experiences but also physiological matters like the individual frequency response of our ears and the brain capacity reserved for audio perception (that may increase -> blind people) ...
I guess my point of view is not for away from yours. But let me explain. I believe that there are two hifi "religions", which have completely equal rights. I often use the terms Master-Hifi and Slave-Hifi.
Master-Hifi: The best music in the world is not very often preserved in the best recordings (for me e.g. The Beatles). We love this music and do everything to make it more enjoyable: Adding 2nd harmonics distortion to reconstruct real harmonics missing in the music (good luck!), warming up the sound (or give it more kick) using certain parts, varying the circuitry, using suitable concepts and so on... The resulting gear is in the best case breathtaking, seductive and loveable. (Yes, I have tube-amps in mind!
But there are also solid states -DIY or not- like Naim, Phonosophie and First Watt F3 - Sorry Papa!)For me these are the "sounding" devices. It's like a second mastering to the (imperfect) recording! But what's the difference!? Listen and enjoy!
Slave-Hifi: The term sounds minor but we'll see. "Clean Hifi" if you want. If it doesn't sound good, blame it on the recording (or the not finished burn-in-period)! An amplifier in this category tries not to sound. It's approximately neutral. Just amplifying the signal. Nothing is added, approximately (nice word
) nothing is taken. The perfect slave to the recording. A slave-amp is merciless to most recordings. But if the recording (and the rest of your gear) is excellent you'll reach the sky!!!Ah, I forget to mention, that any other Hifi, that doesn't fit to one of these categories is for me NoFi.
For me the F5 is the perfect Slave-Amp: Ultra-low distortion, perfect linearity, no "sounding" capacitor in the signal path, only a few parts per channel. So I try to give it the "best" ("neutral") parts of the world market (I hope Michael Percy gets rich with these 12-Bucks-Resistors
) and get happy with it! For me the F5 has only two disadvantages: It's limited power and my monthly electricity bill.
But of course you have every right in the world to transform the F5 into a Master-Hifi-Device, if you forgive me to use this term.
I don't want to do you wrong. I'm sure you have a huge experience in modifying and building amplifiers. If I have done you wrong take my excuse.
Greetings
Martin
P.S.: That Riken resistors are just an additional gimmick - a sort of Master-Hifi-Switch if you want.
