I would extend the wires to the transformer to allow it to be moved, just rotating it 60 degrees can have quite an effect sometimes.
You can get cheap rotary switches which will allow for switching both signal feeds and returns. I built a passive pre last year for a family member using one of these switches and it works very well indeed.
2pc Rotary Switch 2 Wafers 6 Poles 4 Positions SRRN243 L=25mm RoHS FD Taiwan | eBay
You can get cheap rotary switches which will allow for switching both signal feeds and returns. I built a passive pre last year for a family member using one of these switches and it works very well indeed.
2pc Rotary Switch 2 Wafers 6 Poles 4 Positions SRRN243 L=25mm RoHS FD Taiwan | eBay
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Second DavyM,
Twist the primary wires and and have them enter the TX portion of the box in the bottom corner, not underneath the pot. Braid the secondairy from the TX to the board. Your signal wires look OK. Your problem is from the AC. Is your ground from the IEC soldered to the case?
Ron
Twist the primary wires and and have them enter the TX portion of the box in the bottom corner, not underneath the pot. Braid the secondairy from the TX to the board. Your signal wires look OK. Your problem is from the AC. Is your ground from the IEC soldered to the case?
Ron
Make your Protective Earth safer.
Use mechanical connections that cannot fall off !
Your transformer wiring is not twisted.
The big loops at the inputs may be picking up some of the interference from the untwisted wiring.
You have twisted the DC wiring to the indicator LED.
DC wiring does not create the changing fields that are a necessary part of creating interference.
Use mechanical connections that cannot fall off !
Your transformer wiring is not twisted.
The big loops at the inputs may be picking up some of the interference from the untwisted wiring.
You have twisted the DC wiring to the indicator LED.
DC wiring does not create the changing fields that are a necessary part of creating interference.
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Thanks for the tips Andrew. I will see if I can find a nut to properly secure the chassis ground to the lug there. You make a good point. I will also twist xformer wiring. I know the LED didn't need to be twisted -- I just did it for convenience of routing. Thank you for your advice.
alexkosha, Marra: yes the chassis came from Peter Daniels. When I purchased my gainclone "integrated" kit from him years ago this was the chassis that came with it. You can still see pictures of his prebuilt amps using similar enclosures. He no longer sells the integrated kit unfortunately. Since I no longer use the gainclone I decided to repurpose the case. I drilled some new holes for the mosfet mounting, and to move the subchassis divider to make room for the pcb. It looks quite nice in its finished form!
alexkosha, Marra: yes the chassis came from Peter Daniels. When I purchased my gainclone "integrated" kit from him years ago this was the chassis that came with it. You can still see pictures of his prebuilt amps using similar enclosures. He no longer sells the integrated kit unfortunately. Since I no longer use the gainclone I decided to repurpose the case. I drilled some new holes for the mosfet mounting, and to move the subchassis divider to make room for the pcb. It looks quite nice in its finished form!
On the way...
Later will come some Cinemag 15/15 for the balanced input, triggers and a nice front panel.
http://postimage.org/index.php?lang=english
I really like the DCB1. It replaces an Atoll PR200.
Later will come some Cinemag 15/15 for the balanced input, triggers and a nice front panel.
An externally hosted image should be here but it was not working when we last tested it.
http://postimage.org/index.php?lang=english
I really like the DCB1. It replaces an Atoll PR200.
Thanks.
For info the green board with controller board is the LCDUINO, quite a nice piece of hardware and software: The LCDuino-1 display I/O processor
Turntable: Project Debut Carbon - Ortofon 2M Blue
Phono: Simplistic NJFET RIAA
DAC: DDDAC 1794
Amp: Zenquito (currently building a F5)
Speaker: Quadral Montan MK3
For info the green board with controller board is the LCDUINO, quite a nice piece of hardware and software: The LCDuino-1 display I/O processor
Turntable: Project Debut Carbon - Ortofon 2M Blue
Phono: Simplistic NJFET RIAA
DAC: DDDAC 1794
Amp: Zenquito (currently building a F5)
Speaker: Quadral Montan MK3
I remember your nice FSP build, if you had set the amp at about 30dB gain it should be sufficient with vinyl source and dcb1. What is the dBSPL sensitivity of the speakers?
Thanks.
My current amp (zenquito) has a gain of 30dB.
I am usually listening around -20dB (really really loud -10dB).
I plan to set the F5 about 18-20dB gain.
I think the speakers are about 89dB. (Quadral Montan Mk III | Hifi-Wiki.de)
My current amp (zenquito) has a gain of 30dB.
I am usually listening around -20dB (really really loud -10dB).
I plan to set the F5 about 18-20dB gain.
I think the speakers are about 89dB. (Quadral Montan Mk III | Hifi-Wiki.de)
Hello everyone,
Sorry to bother...
Just built up a DCB1 from Tea-bag's Hypnotize kit. Having a bit of shunt trouble. The positive side works fine--giving ~9vdc. The negative side has a problem. None of the bank-of-5 LEDs light up on the Neg side. The end is giving -1.5v. On the input side of R1 I have -18v on the output side of R1 I get -16v (The positive (working) side shows a much larger voltage drop)
When I measure Q1 with power applied I get -16v on the source and -1.5v on the drain. Any thoughts what I may have done wrong? I triple checked all diode and transistor orientations...
Sorry to bother...
Just built up a DCB1 from Tea-bag's Hypnotize kit. Having a bit of shunt trouble. The positive side works fine--giving ~9vdc. The negative side has a problem. None of the bank-of-5 LEDs light up on the Neg side. The end is giving -1.5v. On the input side of R1 I have -18v on the output side of R1 I get -16v (The positive (working) side shows a much larger voltage drop)
When I measure Q1 with power applied I get -16v on the source and -1.5v on the drain. Any thoughts what I may have done wrong? I triple checked all diode and transistor orientations...
If one led is not dead or backwards, breaking the five strong chain, then a Mosfet might be problematic or a Tx secondary wired wrong. Does the three led chain light up in the problematic side?
You can try out the leds are alive one by one still soldered when the system is powered down, by using a 9V battery through 1k or a dmm capable of lighting up an led in diode mode. To directly energize them by touching their pins with test voltage on the pcb's flip side.
You can try out the leds are alive one by one still soldered when the system is powered down, by using a 9V battery through 1k or a dmm capable of lighting up an led in diode mode. To directly energize them by touching their pins with test voltage on the pcb's flip side.
Thanks for your response, Salas!
Didn't expect to get a reply so quickly!
Definitely not the TX. Getting -18v after the filter caps. That would be about right for a 12.5vac secondary, I think.
The 3 LED chain does light up.
I will pick through the LEDs one by one on the 5 LED chain. Also looked at the mosfet testing link from anothe DCB1 post. Will check these out and report back.
Didn't expect to get a reply so quickly!
Definitely not the TX. Getting -18v after the filter caps. That would be about right for a 12.5vac secondary, I think.
The 3 LED chain does light up.
I will pick through the LEDs one by one on the 5 LED chain. Also looked at the mosfet testing link from anothe DCB1 post. Will check these out and report back.
Ha! Looks like its time for the old man to get some glasses!
I had switched one of the IRFP240 for one of thr IRFP9240. That's fixed.
Getting -9.65vdc and 10.4vdc. With a DC offset of 2.6mV and .01mV. Does the shunt voltage difference matter if the DC offset it okay?
I had swapped out several red LEDs for green ones in an attempt to get the right channel below 5mV. Originally it was -12mV. Finally i swapped the right channel B1 jfet pair for another extra set I had kicking around. I could swap some of the red LEDs back in now on the positive side of the shunt to get it more balanced, but.... Does it matter?
On another note: I have it hooked up now and for some reason It's very loud at only 1 click above silent. I'm using a stepped attenuater I have had in other projects, and it has always been fine-- 20k ohm. I must have done something strange. Is it possible I am getting gain out of the B1? Or did I wire up the volume pot backward? (LOL)
Anyway, at one click, it sounds quite stunning!
I had switched one of the IRFP240 for one of thr IRFP9240. That's fixed.
Getting -9.65vdc and 10.4vdc. With a DC offset of 2.6mV and .01mV. Does the shunt voltage difference matter if the DC offset it okay?
I had swapped out several red LEDs for green ones in an attempt to get the right channel below 5mV. Originally it was -12mV. Finally i swapped the right channel B1 jfet pair for another extra set I had kicking around. I could swap some of the red LEDs back in now on the positive side of the shunt to get it more balanced, but.... Does it matter?
On another note: I have it hooked up now and for some reason It's very loud at only 1 click above silent. I'm using a stepped attenuater I have had in other projects, and it has always been fine-- 20k ohm. I must have done something strange. Is it possible I am getting gain out of the B1? Or did I wire up the volume pot backward? (LOL)
Anyway, at one click, it sounds quite stunning!
Swap the 2.4mV channel JFETs between them. Maybe it will adjust to lower offset without tweaking all the other non matches first. Its not much already, but try for best. Actually I had thought to suggest checking the MOSFET type but having a kit with one side working stopped me for were to have had more opposite side ones to mix.
Dcb1 can not pull gain from its sleeve, that's certain. So see what is going on with the pot or the rest of the system. Congrats up to now.
Dcb1 can not pull gain from its sleeve, that's certain. So see what is going on with the pot or the rest of the system. Congrats up to now.
Hi there! I'm still casing the DCB1But this time, I made a bad mistake. I'll try it better next tomorrow, but I'm quite concerned I could have burnt an IRFP2940.
Two questions: is there a method to test it's not totally gone, without applying current? Can I change it with another one, or it should be "paired"?
Thank again!
Marco
Well, it took a month but... unsoldered the IRFP, tested and it is still good. I put it back on the PCB, redid my measurements - 0,8mV/2,0mV , I wish I could do better but I can't notice the difference but I still feel the pain of desoldering small components.
My next question: PCB solder squares are on the "unmarked" side, right? 'Cause I blew one and got away from it..