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A Very Compact Hybrid Amp - Page 89

post #1321 of 2213
Quote:
Originally Posted by rds View Post
...of course the 5mm leads will have to be bent slightly to fit the 3.5mm holes.
Was wondering when you'd de-lurk!

It looks like this is a fairly simple fix (I have already checked the fit in early hum-removal tests.) I'll grab some caps and do a test, then we'll probably update the BoM.

Maybe we can add the 1A heater parts to the Tweaks section...Holland, did you get any temp measurements on the switch reg?

I don't have a thermocouple
post #1322 of 2213
Quote:
Originally Posted by wiatrob View Post
Holland, did you get any temp measurements on the switch reg?
Nope, not yet. I have not implemented the tweak. I'm extremely busy at work and have absolutely no free time during the day. I'll try to get to it this weekend, time permitting.
post #1323 of 2213
Quote:
Originally Posted by rds View Post
Thanks to everyone who made time to solve this hum problem.

My search at Digikey shows that a 50V 330uF Nichicon PW
Good except that is not a low impedance cap.... I'd like to see some sort of low impedance cap there, but it's not as critical that it is low impedance cap as all the others in the heater circuit.


Add me to the hum-less

Only low impedance 35v+ caps I could fit under my PCB were two 100uf - 63 volters. So total 247uf for C3H & no hum whatsoever with tubes that had no hum w/battery heater supply (6922 & 6DJ8 that did have some hum w/stock 47uf C3H).

IOW I find CTH using onboard switcher with 247uF of C3H capacitance indistinguishable from disabled switcher/battery powered heater. It's an even more wonderful amp than it was before

We are done with this issue I think. So just consider pulling stock 47uf C3H & replacing w/10mm dia - 20mm height (max size) 330uf 50V low imped cap.
post #1324 of 2213
hmm, well maybe a Pansonic FM 270uF 50V is a better choice from Digikey. 0.023 ohms is pretty reasonable I think

Wiatrob - when the sh*t hits the fan, I go on lurk
post #1325 of 2213
if anyone going to order the new caps for c3h, let me know.
Can help out with shipping cost.
post #1326 of 2213
Quote:
Originally Posted by rds View Post
Wiatrob - when the sh*t hits the fan, I go on lurk
Typical Canadian....
post #1327 of 2213
Quote:
Originally Posted by rds View Post
hmm, well maybe a Pansonic FM 270uF 50V is a better choice from Digikey. 0.023 ohms is pretty reasonable I think
If that's the highest uF low imped cap w/max 10mm dia X 20mm H that Digikey has available, think it will be fine. On scope I think 220uf + 47uf did not look as good as 330uf + 47uf BUT the 220uf I used was not low imped & based on scoping low impeds did better AFAIR. So think that 270uf is a good choice if ordering from Digikey & that's whats available.

BTW good to look at the Description as well as attribute/column for size... As usual @ Mouser I see differences in the 330ufs shown by my query/link (listed as 10x16 - desc says 10x20, listed as 10x20 - desc says 10x31, etc).
post #1328 of 2213
Quote:
Originally Posted by keyid View Post
if anyone going to order the new caps for c3h, let me know.
Can help out with shipping cost.
Would like to get in on this myself for C3H replacement in my 1st/protoPCB CTH... A mini GB or something for a cap from my Mouser query OR that 270uf Digikey one would be nice... Maybe start another thread for it?

Edit: I've updated my C3H revision guide. Again.
post #1329 of 2213
I have been out of town this week and have missed all the excellent troubleshooting, not that I would have been able to contribute much. I am very excited that a solution has been found. Nice work folks.

I ordered a 35v nichicon pw from digikey, along with a few other things I needed. Sounds like this was premature, so if there is a groupbuy of a more appropriate cap, I would like to get in on it.
post #1330 of 2213
Quote:
Originally Posted by tacitapproval View Post
I ordered a 35v nichicon pw from digikey, along with a few other things I needed. Sounds like this was premature, so if there is a groupbuy of a more appropriate cap, I would like to get in on it.
CFCubed, Runeight and I have been discussing cap choices. I will be ordering some today to confirm functionality, and then I would like to provide all current builders with this part free of charge. We'll change the BoM and add instructions for installing it.

If there are some builders outside the US who wouldn't mind re-shipping caps to their countrymates, that would be great, but not necessary.

I'll have the caps here and tested by Tuesday of next week.
post #1331 of 2213
above and beyond my friend - kudos ..dB
post #1332 of 2213
wiatrob, dont even think of shipping me a cap! no way am i having you buy caps and ship to the uk again - its enough of a service producing the caps, no need to go abover and beyond, but as dbel says, big kudos for offering.

this si a super little amp with the 6n6p.... easily my favourite tube so far - it just wacks out some heat. maybe some longevity issues but i dont care for my personal build.
post #1333 of 2213
wiatrob, that's very generous offer. I will opt out, however. I have boxes full of caps, I've got plenty of 470uF-1000uF/35V-50V caps just lying around.
post #1334 of 2213
Quote:
Originally Posted by adamus View Post
wiatrob, dont even think of shipping me a cap! no way am i having you buy caps and ship to the uk again -SNIP.
Excellent, that's just the response I was looking for!

Seriously, I am happy to provide these to all - the offer is especially aimed at those who are stepping up from easier DIY builds (SS's or CMOYS) I want to make sure they have the full experience this amp can offer.
post #1335 of 2213
Quote:
Originally Posted by wiatrob View Post
Maybe we can add the 1A heater parts to the Tweaks section
What parts need to be upgraded and has anyone tested this yet?
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