I have all the parts for the F5 here and the Covid gives me time to finally built it.
I have the same chassis as the one used by 6L6 and I wonder how hot that one gets in practice.
Would that case be sufficient for a stereo balanced F5, so with two pcbs (4 mosfets) on one heatsink, or would temperature exceed 55 degrees Celsius?
I have the same chassis as the one used by 6L6 and I wonder how hot that one gets in practice.
Would that case be sufficient for a stereo balanced F5, so with two pcbs (4 mosfets) on one heatsink, or would temperature exceed 55 degrees Celsius?
If you have plenty of ventilation above and below the case, 30mm below and at least 100mm above, in order for the chimney effect to work properly.
You may also have to reduce the bias a little.
The worst that would happen is the necessity for a fan, and there are very quiet fans available. I'd build it and see how it works.
You may also have to reduce the bias a little.
The worst that would happen is the necessity for a fan, and there are very quiet fans available. I'd build it and see how it works.
Other Brands of Toroidal Transforers
I have all the parts for a "DIY-Store Ver 3.0" power supply board. I am using 22000uF 35 volt capacitors. I am going to power an F5 Version 3 power amp from the DIY store. I want to use an "Antek" AS-3218 or an AS-4218. These two transformers have been out of stock for quite sometime. I called customer service and was informed that a shipment would arrive in 2 or 3 weeks.
Is there another brand that is available? The "Plitron" web site is busted. Has anyone used a "Torid" https://toroid.com transformer with the same specifications as the two anteks mentioned. If someone has, could you suggest a model number.
I assembled an "ACA 1.6" I bought myself for Christmas. I had forgotten how good 2 channel music sounds. I had a "Big Ole Stereo" while I was in college. Somehow it got lost in the last 40 years. Thank God and Nelson Pass I kept all "487" of my Vinyl Albums. I don't know who invented "MP3" codec but I am going to punch them in the mouth when I get home.
Anyway back to the topic, I need more power. I think the F5 will fit the bill nicely.
I have all the parts for a "DIY-Store Ver 3.0" power supply board. I am using 22000uF 35 volt capacitors. I am going to power an F5 Version 3 power amp from the DIY store. I want to use an "Antek" AS-3218 or an AS-4218. These two transformers have been out of stock for quite sometime. I called customer service and was informed that a shipment would arrive in 2 or 3 weeks.
Is there another brand that is available? The "Plitron" web site is busted. Has anyone used a "Torid" https://toroid.com transformer with the same specifications as the two anteks mentioned. If someone has, could you suggest a model number. I assembled an "ACA 1.6" I bought myself for Christmas. I had forgotten how good 2 channel music sounds. I had a "Big Ole Stereo" while I was in college. Somehow it got lost in the last 40 years. Thank God and Nelson Pass I kept all "487" of my Vinyl Albums. I don't know who invented "MP3" codec but I am going to punch them in the mouth when I get home.
Anyway back to the topic, I need more power. I think the F5 will fit the bill nicely.
More F5 Version 3 Questions
Thanks for the quick reply quys. Couple of quick questions.
Would the 20volt transformers create more heat?
Are these good for the back panel switch fuses.
021302.5MXP Littelfuse | Mouser
Thanks
Thanks for the quick reply quys. Couple of quick questions.
Would the 20volt transformers create more heat?
Are these good for the back panel switch fuses.
021302.5MXP Littelfuse | Mouser
Thanks
Did the insulation wear off the thermsiter or did the lead get grounded? For this reason I put heat shrink on mine.
I'm pretty sure the insulation had a flaw. I think the MOSFETs were blown because it made contact to ground, but the thermistor turned to smoke and fire on round two because I had the bias turned all the way down and the current had nowhere to go except through the thermistor. The MOSFETs survived that. I went through and put heat shrink tubing on all the other ones and have them biased up to about 1.41 amp. I'm not seeing any significant DC offset drifting around on account of the different heat sinks. The amps are very stable and quiet and I managed to get a slight hum out of them that I'd had in the stereo configuration. I'm happy with them.
I'm using AN-6224 transformers in mine and getting about 33V rails. The LSJ74's don't seem to have a problem with a bit more voltage than they're rated for so if you see 26 or 27 volts on your power supply before you bias it up, it's nothing to worry about. I've been pushing 32+ volts through the LSJ74's for several years now.
Thanks! That being the case, how many VA should I realistically go for? I'm trying to avoid the additional cost of getting all those caps for a second psu, plus running out of walnut for my cases. Is there much of an audio advantage to having two separate psu's in sound quality? I'm bi-amping with an active crossover. I can just fit the antek 500 & 600va toroids in my existing psu case if need be.
Bigger power supplies are always better in class A amps, but there is a point of diminishing returns. For an F5 I'd say that would be about a 600VA transformer and 120,000uF of supply filtering. I haven't noticed much of a difference in using 2 of those sized power supplies in monoblocks. Channel separation is a little bit better though. That sized transformer did get a little warm powering 2 channels. The strength of the power supply is hard to over-estimate. An amplifier is nothing more than a circuit designed to modulate the output of a power supply so the quality of that power supply is very important.