More wasted space

jerluwoo · 7th March 2007, 03:48 AM

Havnt had a connection for a bit so Im posting this up from a friends house. This is a very nice sounding little hybrid amp that i built recently. schematic is in 2 parts starting with the tube front end. I could tell you how i think this arraingement works but it would probly be false and misleading and im not in the habit of spreading propaganda. have fun and enjoy.

p.s. sorry for th e poor quality just did them up quick with paint.

jerluwoo · 7th March 2007, 03:52 AM

here is the transistor output section. the 20k pot sets offset and the 100 pot set bias current.

SY · 7th March 2007, 11:20 AM

Try cutting out the bypass cap across the LED. You might be pleasantly surprised.

Sheldon · 8th March 2007, 12:52 AM

Quote:

Originally posted by SY
Try cutting out the bypass cap across the LED. You might be pleasantly surprised.

I've wondered about this. In principle, the cap shouldn't have much work to do there, so shouldn't have a major effect. But of course, subtle cues are another matter. What kind of effects have you noticed?

Sheldon

SY · 8th March 2007, 01:06 AM

rdf did some work on this and found it to be a detriment. When you calculate how much capacitance you need to effectively bypass something with a 5 or 6 ohm impedance, you're talking about a pretty big cap, so the bypassing may be adding more than it's taking away.

Sheldon · 8th March 2007, 02:07 AM

Quote:

Originally posted by SY
rdf did some work on this and found it to be a detriment. When you calculate how much capacitance you need to effectively bypass something with a 5 or 6 ohm impedance, you're talking about a pretty big cap, so the bypassing may be adding more than it's taking away.

Hadn't thought of it that way. So it "suck it and see" as our friends from down unda might say.

Sheldon

jerluwoo · 8th March 2007, 03:23 AM

just a quick post of the power supplies i used.first the tube section.

jerluwoo · 8th March 2007, 03:24 AM

the ss section.

jerluwoo · 8th March 2007, 03:25 AM

Thanks for the tip SY will try removing the cap when I get home.

jerluwoo · 1st May 2007, 08:24 PM

Yes Sy eliminating the cap made a small but noticable difference. It seemed to make the amp sound "faster" most noticably in the midbass area. Made a couple of changes as well to schematic. I eliminated feedback alltogether and raised the 2.2k resistor in the tube section to 4.7k to raise the gain and eliminate the need for a preamp. It sounds much more open without the feedback and seems much easier for the source to drive it.

7th March 2007, 11:20 AM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Try cutting out the bypass cap across the LED. You might be pleasantly surprised. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

8th March 2007, 01:06 AM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	rdf did some work on this and found it to be a detriment. When you calculate how much capacitance you need to effectively bypass something with a 5 or 6 ohm impedance, you're talking about a pretty big cap, so the bypassing may be adding more than it's taking away. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What would you do with this space? Horns?	electricashman	Multi-Way	5	1st August 2007 05:19 PM
I need space.	kiowamec	Multi-Way	3	22nd May 2006 06:26 AM
Pic: 20 years old wasted on Xmas!	Prune	Everything Else	5	27th December 2004 10:01 AM
Not enough space?	WhtCastle	Everything Else	7	28th November 2001 02:46 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

8th March 2007, 03:25 AM	#9
jerluwoo diyAudio Member Join Date: Feb 2006 Location: Ashland,Ky U.S	Thanks for the tip SY will try removing the cap when I get home.

1st May 2007, 08:24 PM	#10
jerluwoo diyAudio Member Join Date: Feb 2006 Location: Ashland,Ky U.S	Yes Sy eliminating the cap made a small but noticable difference. It seemed to make the amp sound "faster" most noticably in the midbass area. Made a couple of changes as well to schematic. I eliminated feedback alltogether and raised the 2.2k resistor in the tube section to 4.7k to raise the gain and eliminate the need for a preamp. It sounds much more open without the feedback and seems much easier for the source to drive it.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)