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DIY Workshop ŧ The YAHA amp thread part 2 fa-schmidt Headphone Council Joined: Dec. 7, 2001 |  Message [#1] posted on: 08-30-2005 04:23 AM CST (US).   |  |  To be continued from: |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#2] posted on: 08-30-2005 04:24 AM CST (US). | | Last relevant posting was from evo: Hi fa-schmidt, i am powering your YAHA from a SMPS i bought on another forum and it sound much better than the PSU i made- its made the sound more detailed and i can hear some things more clearly |
| evo HeadWizer Joined: Jul. 18, 2004 | Message [#3] posted on: 08-30-2005 01:33 PM CST (US). | | Also using one of these in the next mains electrical socket: DIY Audio HiFi Mains Filter - The Parallel Unit Attachment: C1064.jpg |
| tbanasik HeadWizer Joined: N/A | Message [#4] posted on: 08-30-2005 02:04 PM CST (US). | | Thanks for responses to my question. I have one more ;). In buffered YAHA by Sijose, buffer chip is powered by single supply. Can I power diamond buffer the same way ( in this case the most convinient ), or I will have to use dual PSU for the latter? Thx. |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#5] posted on: 08-31-2005 01:10 AM CST (US). | | The diamond can work with single supplies, too. If you donīt forget the output cap ! |
| paskal Member Joined: Aug. 31, 2005 | Message [#6] posted on: 08-31-2005 02:18 AM CST (US). | | i've been reading the forum for quite sometime now without registering. but this Multi-Hybrid headamp really caught my interest. is there any way that i could take out the eletrolytic cap from the signal path? i know DC offset would prove deadly while on/off, but is there any way to remove the DC offset by any other method other than output caps? dual power supplies perhaps? as for the suggestion by animal_mother, anyone have any thoughts? |
ericj HeadWize Fanatic Joined: Aug. 1, 2005 | Message [#7] posted on: 08-31-2005 09:30 AM CST (US). | | Someone suggested getting some really enormous "motor run" caps - basically cheap film caps that you can find as big as 500uf. They'd be bigger than the amp. I'm not sure if they were joking. I hear that if you bypass the electrolytic with the same sort of film cap you put on an input, the performance is improved. |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#8] posted on: 09-01-2005 01:22 AM CST (US). | | paskal: You could get rid of the electrolytic cap with a dual supply. animal_mother had an appropriate suggestion in part 1 of this thread. It has to be worked out. Maybe iīll do a Pspice sim the next days. Since itīs easy now to post pics there is a chance you see it soon... ericj: Bypassing an electrolytic with a small film cap is one method
600 Ohm --> 53uF The biggest film caps from WIMA (MKS4) that are commonly available |
| ChrioN HeadWizer Joined: Jun. 6, 2005 | Message [#9] posted on: 09-01-2005 04:44 AM CST (US). | | fa-schmidt, how did you power the 4556 opamp? did you use a single power supply? +12vdc to + on the opamp? |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#10] posted on: 09-01-2005 05:13 AM CST (US). | | I use a single ps. +12VDC go to the + pin of the opamp and ground goes to |
| tubesmuggler Member Joined: Apr. 22, 2005 | Message [#11] posted on: 09-01-2005 01:36 PM CST (US). | | For the output cap, what voltage should it be rated for? I have some 470uF/6.3VDC Nichicon on hand. TIA |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#12] posted on: 09-01-2005 01:49 PM CST (US). | | Theoretically the opamp output should sit nearly at half the supply voltage. That said the 6.3 Volt caps should be ok. But: You should have some safety margin in case of circuit failure. You donīt want to risk damaging your headphones so you better |
| Tomo Headphone Council Joined: May 4, 1999 | Message [#13] posted on: 09-03-2005 01:58 AM CST (US). | | Hey, I wouldn't use those 6.3V. Those voltage tolerance you see on electrolytics are NOT the suggested operating voltage. You want to operated the electrolytics at slighterly lower voltage than it's maximum tolerance. I would take Fa-Schmidt's advice and buy 16Ver's. Of course, that does NOT mean this is mission-critical. You can use your 6.3Ver to test-build your amp. If you like it and you want to use some more, you should replace your 6.3Vers with 16V caps (or higher). Tomo P.S. I do have 6.3Ver's too. I know the itch to use them. :) |
| evo HeadWizer Joined: Jul. 18, 2004 | Message [#14] posted on: 09-05-2005 10:54 AM CST (US). | | Tried building this version: It works fine without the batteries-but not with? Attachment: C1067.gif |
| ericj HeadWize Fanatic Joined: Aug. 1, 2005 | Message [#15] posted on: 09-06-2005 10:26 AM CST (US). | |
Per side, yes. |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#16] posted on: 09-07-2005 03:57 AM CST (US). | | Yes, per side. But why ? I did not get it. Lifting the cathode potential is like having a dual supply. Maybe the trick is to adjust the buffer input to zero volt and thus having the output capless ? But beware, this is an assumption. |
| evo HeadWizer Joined: Jul. 18, 2004 | Message [#17] posted on: 09-07-2005 03:59 AM CST (US). | | Ok firstly i built Sijosae's version of this amp, but for simplicity i ommited the batteries. The only other change is the 47k variable, i made a fixed 47.5k as thats what i had. The circuit worked 1st time and sounds good with slightly more "punch" than my YAHA, but when i tried to connect the batteries it sounds terrible. Any ideas? thanks |
| tubesmuggler Member Joined: Apr. 22, 2005 | Message [#18] posted on: 09-07-2005 03:37 PM CST (US). | | OK I've got my YAHA put together...and have a lot of distortion. Not measured, but just plain loud distortion as loud as the music. I'm using a Marantz CD67SE for source. My test phones were AKG240DF. I have tried different tubes with no changes. I will try low impedance phones tomorrow. I have 46K plate resistor and voltages on pins 1 and 6 is approx 7V. The changes I have made are: NE5322 For clarification please tell me - I connect the 5322 pin 2 to pin 1, and pin 6 to pin 7 correct?? Leaving pin 4 and 8 unused? I have never used these things before! I noticed ChrioN asked a few post ago about "-" connected to ground, but I don't see this on the schematic. I see "-" connected to the output. This is not hiss or hum so I do not think the problem is filtering or the PS...but of course I really don't know. Any tips?? TIA [Edited by tubesmuggler on 09-07-2005 at 03:59 PM.] |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#19] posted on: 09-08-2005 01:13 AM CST (US). | | So far no problem with the psu. Without input cap this amp wonīt work. Maybe the plate resistor needs some adjustment after you put in the input cap. Connecting 2 and 1 resp. 6 and 7 of the opamp is correct, too. The opamps non-inverting inputs 3 and 5 go to the pin no. 1 and The opamp pin 4 goes to ground and the pin 8 goes to + (plus) of Never forget the output cap. [Edited by fa-schmidt on 09-08-2005 at 01:14 AM.] |
digi01 HeadWize Fanatic Joined: Dec. 3, 2002 | Message [#20] posted on: 09-08-2005 04:09 AM CST (US). | | I have made a comparable amp with a switzerland diyer.the tube stage is powered by bipolar supply +/-60VDC,the output stage is inverting LM3875 power IC. fa-schmidt,have you consider modify the power supply with bipolar 2 9V batteries?then can remove the input and output caps. Attachment: C1074.jpg,C1075.jpg |
| fa-schmidt Headphone Council Joined: Dec. 7, 2001 | Message [#21] posted on: 09-08-2005 07:35 AM CST (US). | | Amazing ! Thanks for sharing the pics. Yes, there have been suggestions to power the amp off a bipolar At the moment priority was to have a simple power supply, |
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Đ Chu Moy, 2001.