Actually that's the confusing part..
The original BOM describes C1-C3 as Polyprop Wima but the cat no. shown is Mouser MKS4 series which are Polyester; https://www.wima.de/en/our-product-range/metallized-capacitors/mks-4/
Not a big fuss but I prefer using polypropylene ;-)
Thanks for making your design available to use all, can't wait to hear it.
Eric
The original BOM describes C1-C3 as Polyprop Wima but the cat no. shown is Mouser MKS4 series which are Polyester; https://www.wima.de/en/our-product-range/metallized-capacitors/mks-4/
Not a big fuss but I prefer using polypropylene ;-)
Thanks for making your design available to use all, can't wait to hear it.
Eric
Yes, PP caps from WIMA would be too large ... the physically smallest WIMA 3.3 uF PP would be MKP4 at 100V DC, which have a lead spacing of 27.5 mm. So I went with the Panasonic PP caps as well.
And I can only second what Eric said - may thanks to you, Nelson, for the design and the kits !
I absolutely love this Front End, and it is currently my favourite preamp. It is actually the first preamp where I liked the sound of an Alps Blue pot as volume control ... have it set up with a relay-controlled resistive attenuator now, however.
And I prefer LSK170 (single) or 2SK209 (paralleled) over paralleled J113.
Regards, Claas
And I can only second what Eric said - may thanks to you, Nelson, for the design and the kits !
I absolutely love this Front End, and it is currently my favourite preamp. It is actually the first preamp where I liked the sound of an Alps Blue pot as volume control ... have it set up with a relay-controlled resistive attenuator now, however.
And I prefer LSK170 (single) or 2SK209 (paralleled) over paralleled J113.
Regards, Claas
There is a nice set of drawings and documentation that was put together by 6L6 showing how to connect a single rail voltage rather than the default bipolar configuration displayed in Nelson’s article. However, it only covers single ended input rather than balanced. Is it possible to use a single rail voltage with a balanced input? If, for example, I was to use a 48V positive PS, could I hook the -IN ground to the V- as with the +IN ground and obtain a balanced input?
Hi, can anyone advise me on grounding for this project. I built a F6 and used a CL60 to lift the ground. The way I currently have assembled my Fe2022 I have no ground to the chassis. I am using a smps power supply with a plastic barrel socket. I have a slight hum when hooked up to my F6 and as well I can make it buzz when I touch the volume control.
Thanks for your help.
Thanks for your help.
),
Finally got two working cards in single ended. I blew one, had to wait for the store to re-stock to build another board. I tested by cell phone music into earbuds and got the same output from each card with proper voltage applied.
I reversed the - and+ for just a second on the blown card once, got smoke, so I may have lunched the class A transistor, but I don't have the equipment or the chops to test. I cleaned everything, checked the resistors and the solder joints etc. etc. it still didn't work from input to output.
It was easier in my situation to build another card. I will get another transistor later and try and test later on the blown card, but for now, the two that seem to work will go into my OS2 SK60 in the TA 4650 chassis.
The chassis has tons of inputs, so I will keep the inputs and outputs of these cards separate from the amp input, and it will also allow me the option of inputting other voltage amps to the amp input. So the 4650, if this works, will have the volume controlled 4650 preamp AND these cards as options for inputs. OS2 to my delight has been going strong for six months and seems stable in operation. It is a special sounding amp, my other great amps have gotten lonely.
I reversed the - and+ for just a second on the blown card once, got smoke, so I may have lunched the class A transistor, but I don't have the equipment or the chops to test. I cleaned everything, checked the resistors and the solder joints etc. etc. it still didn't work from input to output.
It was easier in my situation to build another card. I will get another transistor later and try and test later on the blown card, but for now, the two that seem to work will go into my OS2 SK60 in the TA 4650 chassis.
The chassis has tons of inputs, so I will keep the inputs and outputs of these cards separate from the amp input, and it will also allow me the option of inputting other voltage amps to the amp input. So the 4650, if this works, will have the volume controlled 4650 preamp AND these cards as options for inputs. OS2 to my delight has been going strong for six months and seems stable in operation. It is a special sounding amp, my other great amps have gotten lonely.
I hooked up the cards with external inputs and outputs then into the OS2 in the Sony TA 4650 chassis build. Room was a problem in the crowded milieu. Picture shows them tucked neatly under the front. Wiring was mostly rearranging the wire already in the unit.
I attached them single ended riding off the 36v power supply that powers the OS2. That doesn't seem to be a problem.
Blessedly with bated breath, I hooked it up to some 3.6 ohm full range panels @88db sensitivity. It worked! Nothing fizzled, sparked, smoked or made funny smells, just worked.
Seems like lots of gain. Even without break in or warm up, the sound is sweet, clean and ethereal, even with a non-ideal speaker. I probably can't hear any increase in distortion due to the somewhat lower than recommended voltage.
I attached them single ended riding off the 36v power supply that powers the OS2. That doesn't seem to be a problem.
Blessedly with bated breath, I hooked it up to some 3.6 ohm full range panels @88db sensitivity. It worked! Nothing fizzled, sparked, smoked or made funny smells, just worked.
Seems like lots of gain. Even without break in or warm up, the sound is sweet, clean and ethereal, even with a non-ideal speaker. I probably can't hear any increase in distortion due to the somewhat lower than recommended voltage.
Attachments
Hi
While assembling a pcb set for a friend of mine, a made a mistake and destroyed Q5 on one channel.
I have an order almost ready from Mouser so could someone recommend a replacement for Q5 that’s stock at Mouser since they are out of KSA992.
Most of what I need is not available at Digikey so for this time I’m stuck with Mouser.
Thanks,
Eric
While assembling a pcb set for a friend of mine, a made a mistake and destroyed Q5 on one channel.
I have an order almost ready from Mouser so could someone recommend a replacement for Q5 that’s stock at Mouser since they are out of KSA992.
Most of what I need is not available at Digikey so for this time I’m stuck with Mouser.
Thanks,
Eric
