Unless my DVM and math are lying to me since I saw around half a volt across the 2.7 ohm resistors, the 200 mA is there. It's not that much power either: 15V x .2A is only three watts, and I got the tallest heatsink which would fit in a 2U chassis. The regulators are similarly heatsunk, and they're even lower dissipation: 400 mA through a 3 or 4 volt drop is about 1.5 watts-ish. I've fixed way too much gear designed by other engineers to neglect heat considerations: junction temperatures in my stuff never exceed 60C.
I didn't bother comparing it with the stock design because that meant putting in a bunch of parts only to change them later. As for increasing the resistor values, remember I have a stonking inductor before the CRCRC stage, which reduces the ripple considerably. 400 mA through a 1 ohm resistor (had to reduce them because the inductor has non-negligible resistance) is about a sixth of a watt. No biggie.
If that isn't enough there's also a Noctua fan running undervolted through its very own regulator. Incidentally, fans are funny beasts: current draw through the dropping resistor was decidedly not steady (looked like a high-passed square wave, if anything) so a 1000 uF capacitor got jammed in between the resistor and the fan to keep the ground return from bouncing.
I didn't bother comparing it with the stock design because that meant putting in a bunch of parts only to change them later. As for increasing the resistor values, remember I have a stonking inductor before the CRCRC stage, which reduces the ripple considerably. 400 mA through a 1 ohm resistor (had to reduce them because the inductor has non-negligible resistance) is about a sixth of a watt. No biggie.
If that isn't enough there's also a Noctua fan running undervolted through its very own regulator. Incidentally, fans are funny beasts: current draw through the dropping resistor was decidedly not steady (looked like a high-passed square wave, if anything) so a 1000 uF capacitor got jammed in between the resistor and the fan to keep the ground return from bouncing.
You could try using an infrared thermometer to measure each transistor's case temperature; then Tjunction = Tcase + (theta_JC * PowerDissipated).
For the output transistors which drive the headphones, datasheet theta_JC varies between 3.1 degC/Watt (Toshiba) and 3.5 degC/Watt (Vishay). Using the average value 3.3, we find Tjunction = Tcase + 10 degC. So if your infrared thermometer says the case temperature is, let's suppose 140F {equals 60C}, then the junction temperature is 158F {equals 70C}.
For the output transistors which drive the headphones, datasheet theta_JC varies between 3.1 degC/Watt (Toshiba) and 3.5 degC/Watt (Vishay). Using the average value 3.3, we find Tjunction = Tcase + 10 degC. So if your infrared thermometer says the case temperature is, let's suppose 140F {equals 60C}, then the junction temperature is 158F {equals 70C}.
Since the TO-220 tab is 50C then the junction is at 60C, just the way I like it. I ran the numbers before hitting the Big Red Button but confirmation is nice.
WHAMMY as pre-amp!
I tested my newly built WHAMMY in place of my Conrad Johnson Premier 17 valve pre-amp in my main system tonight. I was shocked. The sound blew me away - so much more crisp than the valves, much more clean bass and sparkle. The soundstage felt a little bit smaller and the female voices a little less smooth / warm, but that is the valve sound. My ears actually prefer the rawness of WHAMMY.
Decisions now - do I build another WHAMMY with a motorized volume pot and no headphone output as a dedicated pre-amp or will I get even better, more raw and crisp sound from other DIY designs (e.g. PassDIY buffer pre-amp)?
For the $600 or so that I spent, the WHAMMY is truely amazing. Still enjoying the shot of energy it gave my Audeze LDC-X.
I tested my newly built WHAMMY in place of my Conrad Johnson Premier 17 valve pre-amp in my main system tonight. I was shocked. The sound blew me away - so much more crisp than the valves, much more clean bass and sparkle. The soundstage felt a little bit smaller and the female voices a little less smooth / warm, but that is the valve sound. My ears actually prefer the rawness of WHAMMY.
Decisions now - do I build another WHAMMY with a motorized volume pot and no headphone output as a dedicated pre-amp or will I get even better, more raw and crisp sound from other DIY designs (e.g. PassDIY buffer pre-amp)?
For the $600 or so that I spent, the WHAMMY is truely amazing. Still enjoying the shot of energy it gave my Audeze LDC-X.
not saying that it's better than WHAMMY ( Wayne is Wayne), but certainly worth checking (color me biased here) - Iron Pre
not just cheap as **whatever, but also pretty good sounding ........ slightly different to WHAMMY
edit: CJ P17 - with gain of 26db - it means it's simply depraved, if using modern sources (most of them having 2Vrms out) and normal gain power amps (most of them asking 1V5-2V5rms for full blast)
CJ P17 - good to mate with, say, F4 or any other no gain-follower type of builds around
not just cheap as **whatever, but also pretty good sounding ........ slightly different to WHAMMY
edit: CJ P17 - with gain of 26db - it means it's simply depraved, if using modern sources (most of them having 2Vrms out) and normal gain power amps (most of them asking 1V5-2V5rms for full blast)
CJ P17 - good to mate with, say, F4 or any other no gain-follower type of builds around
Pre-amplifiers are like socks you need more one pair.
my personal advice: Don't use a device for something it wasn't designed for. In this case: The Whammy is an excellent HPA, but for a pure preamp, you actually don't need any gain. With the Whammy, you would add complexity that could be avoided and is really not needed. I have both the Whammy and the B1 buffer, and of course I tested both as preamps. IMHO, use the B1 as a preamp and the Whammy as a HPA. You won't be disappointed. (and yes, the whammy works perfectly well as a preamp, but the B1 surpasses it for this job).
Well...I disagree on this one. there are some devices out there that are so good in all aspects that you really don't need more than one! And frankly, since I built the Whammy, I don't use my Lehmann Linear Pro anymore...
I listen to the CJ again - I love the sound but would like some more slam. I have a Purify-based power-amp - very fast and clean with load of power, especially base. It sounded unleashed with the WHAMMY but a little tame with the CJ. Tell me more about the no-gain follower build, please.
just search for F4 here
https://www.diyaudio.com/community/threads/a-guide-to-building-the-pass-f4-amplifier.234355/latest
and you can also search for recent SIT Follower amps builds, well and few other ones
Guys will chime certainly with proper links
there are several of them around, I can remember right from the bat only few:
https://www.diyaudio.com/community/threads/build-this-mofo.313649/
https://www.diyaudio.com/community/...14-choke-loaded-source-follower.400792/latest
https://www.diyaudio.com/community/...ion-vfet-tdv-amp-using-2sk2087c.388926/latest
https://www.diyaudio.com/community/...drain-mu-follower-amplifier-45w.371187/latest
https://www.diyaudio.com/community/threads/a-guide-to-building-the-pass-f4-amplifier.234355/latest
and you can also search for recent SIT Follower amps builds, well and few other ones
Guys will chime certainly with proper links
there are several of them around, I can remember right from the bat only few:
https://www.diyaudio.com/community/threads/build-this-mofo.313649/
https://www.diyaudio.com/community/...14-choke-loaded-source-follower.400792/latest
https://www.diyaudio.com/community/...ion-vfet-tdv-amp-using-2sk2087c.388926/latest
https://www.diyaudio.com/community/...drain-mu-follower-amplifier-45w.371187/latest
I'm going to build the Iron Pre (just to compare it with a valve pre-amp which is my current preferred option.) But while clearing out the holiday home
over the last few days my listening has been restricted to Satellite radio on the TV, due to bad planning. Frankly, it's been background, forgettable noise. Today I found a couple of leads tucked away in a drawer, so dug out a pair of entry-level floorstanders I was going to leave with the furniture, hooked them up and Wow! Music.
Using a decent DAC with a WHAMMY, I'm reminded again that source + pre-amp trumps everything else. The best amp you can build is great, and reviewers I trust seem to agree that speakers are improving all the time, but provided that both are adequate it's what you feed them that transforms noise into magic.
I hesitate to recommend anything I've built: expectation bias is not to be trusted. But the WHAMMY (with a couple of fancy output caps to satisfy that bias) is great fun. Thanks again, Wayne.
over the last few days my listening has been restricted to Satellite radio on the TV, due to bad planning. Frankly, it's been background, forgettable noise. Today I found a couple of leads tucked away in a drawer, so dug out a pair of entry-level floorstanders I was going to leave with the furniture, hooked them up and Wow! Music.
Using a decent DAC with a WHAMMY, I'm reminded again that source + pre-amp trumps everything else. The best amp you can build is great, and reviewers I trust seem to agree that speakers are improving all the time, but provided that both are adequate it's what you feed them that transforms noise into magic.
I hesitate to recommend anything I've built: expectation bias is not to be trusted. But the WHAMMY (with a couple of fancy output caps to satisfy that bias) is great fun. Thanks again, Wayne.
I'm back home now, and the WHAMMY is still in France, but from memory, a couple of Auricaps that I already had on the shelf; not all that fancy (expensive) but they work. I like to screw down the lid on a finished project and move on to the next without wondering whether it could have been a fraction better. 🙂
Have you tried other mods, besides fancy caps? I've found the biggest improvement with the discrete opamps. Still, a few mods ahead of me.
That makes sense - I seem to remember swapping a dual op-amp but I can't remember what I finished up with in the end. As noted above, my WHAMMY is some 500 miles away right now.
Hey there. Bought a WHAMMY full kit a couple of months ago and just now getting to it.
Unfortunately there were no 5.1 ohm resistors in the kit so I'm looking to get some replacements. The schematic and PCD just say 5.1. What are the wattage and tolerance I need?
Thanks
Unfortunately there were no 5.1 ohm resistors in the kit so I'm looking to get some replacements. The schematic and PCD just say 5.1. What are the wattage and tolerance I need?
Thanks
The resistors should be rated 3W for 5,1 Ohm, the simplest wirewound or ceramic resistors are perfect here (they add some inductance, which is a good thing). There's absolutely no need at all to get fancy parts and/or tight tolerances here.
If you have the 2x22V sec transformer, I would recommend to increase the R value (and also the wattage!). In my case I use two 22Ohm 3W resistors in parallel on each spot (see my post #4911). You could also simply use a 10Ohm or 11Ohm resistor, but make sure they are at least rated 5W in that case. It increases the filtering capacity of the CRCRC filter while keeping the input voltage of the regulators a bit lower (so they run a bit cooler). Only advantages, no disadvantages.
If you have the 2x22V sec transformer, I would recommend to increase the R value (and also the wattage!). In my case I use two 22Ohm 3W resistors in parallel on each spot (see my post #4911). You could also simply use a 10Ohm or 11Ohm resistor, but make sure they are at least rated 5W in that case. It increases the filtering capacity of the CRCRC filter while keeping the input voltage of the regulators a bit lower (so they run a bit cooler). Only advantages, no disadvantages.