Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A Very Compact Hybrid Amp
New Posts  All Forums:Forum Nav:

A Very Compact Hybrid Amp - Page 93

post #1381 of 2203
5/21/09 at 12:36pm
Quote:
Originally Posted by holland View Post
Just curious as to what everybody's 6.3V voltage is at? Mine is low (measured it last weekend but didn't have time to do anything other than take a quick measure), going to change R3 to 7.5K which should bring it up to 6.3V.
Edit: Forget I said this: "Would be interested what voltage your 12.6V setting would then be." R3H is not involved in 12.6v setting.

6V heater setting is combo of R1H & R3H values. I get like 6.18V (6.2V) & 12.57 (12.6V) with BoM values AFAIR. Played a bit with *available* values for those resistors & decided the BoM values were good enough. SMS app values for them were accurate AFAIR.

Edit: The 6.2V was with target heater load & BoM values. Perhaps there is an ever-so-slightly better available R3H value tho (to get exactly 6.3v). AFAIR the ideal value for std heater loads was closer to BoM 6.98k then to 7.5k. Maybe like 7.1416k? Not something I'm loosing sleep over
Reply
post #1382 of 2203
5/21/09 at 1:32pm
I get slightly low, 6.15v. Doesnt bother me to be honest, there is certainly no lack of warmth (something i found with the my bijou that had low heaters)
Reply
post #1383 of 2203
5/21/09 at 2:27pm
Cool, thanks. Going to bring that up in time, to see the impact. Re: adamus & Bijou. Currently running my Bijou @ 6.5V heaters.
Reply
post #1384 of 2203
5/21/09 at 2:51pm
with 6n1p in the front end i ran mine hot too, definately a richer sound. With a 6dj8 in the front, i stick at 6.3v.
Reply
post #1385 of 2203
5/21/09 at 3:05pm
If I recall correctly, my 6V measurement was rigjt around CFCubed's. I can't hear those subtle differences...
Reply
post #1386 of 2203
5/21/09 at 8:18pm
Quote:
Originally Posted by smeggy View Post
here's a pic of my CTH made from old leftovers, old top plate I had made 4-5 years ago for another unfinished project, bit of old walnut, computer speaker grille and other sundry bits I had in the scrap bin.

I still need to wire in the new pot, RCAs, power and fix the headphone sockets in place. Make a base frame, add feet and await my black knob from Hong Kong, but you can see the basic idea.



I call it 'MOAR DARK'
Wood Etch-a-Sketch?
Reply
post #1387 of 2203
5/21/09 at 9:12pm
...with moar dark
Reply
post #1388 of 2203
5/22/09 at 1:34am
Quote:
Originally Posted by rds View Post
My search at Digikey shows that a 50V 330uF Nichicon PW is the best option for the BOM case
Quote:
Originally Posted by cfcubed View Post
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.
I just clicked these links. :P

I'm not sure I see a difference. Nichicon PW is low impedance (0.090ohm @ 100KHz & 20C ESR) and the link from rds is the same you are pointing to. I think?

Anyhow, Nichicon PW FTW.
Reply
post #1389 of 2203
5/22/09 at 1:57am
Quote:
Originally Posted by holland View Post

Anyhow, Nichicon PW FTW.
I'm staring at a sackful here on the bench Let me know if you want a couple...
Reply
post #1390 of 2203
5/22/09 at 2:00am
Thanks for the offer, but I'm good. I used Panny FM 470uf/35V from my stash.
Reply
post #1391 of 2203
5/22/09 at 3:01am
As for under-heated tubes - 7DJ8s can be added to the list as well.

Silent @ zero volume with the 330uH and very nice sounding...
Reply
post #1392 of 2203
5/22/09 at 4:14am




I really like this amp
Reply
post #1393 of 2203
5/22/09 at 7:15am
Quote:
Originally Posted by rds View Post
I really like this amp
That's what we like to hear. The whole point of the adventure for me.

Great looking build.... Belongs in the CTH build gallery
Reply
post #1394 of 2203
5/22/09 at 7:26am
Smeggy and RDS, nice looking amps!
Reply
post #1395 of 2203
5/22/09 at 10:29am
Quote:
Originally Posted by wiatrob View Post
As for under-heated tubes - 7DJ8s can be added to the list as well.

Silent @ zero volume with the mods and very nice sounding...

Talking of underheated tubes, got what was supposed to be two 6FQ7/6CG7 tubes from eBay today. One is fine, but the second is a 8FQ7/8CG7(8.4V heater), was going to return it for a refund but after reading your post plugged it in and it sounds great even at only 6.3V!

Have only had a short listen today but the 6CG7 sounds fantastic, one of my favorite tubes already.
Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A Very Compact Hybrid Amp