[L0rdGwyn]

i did something similar to a mates darkvoice. CCS made a big difference. Caps then helped. Power supply was icing on the cake, but least noticable after the other mods. I assume because the cascode CCS was such a brickwall to power supply noise... wouldnt stop me though!

Very nice! What did you end up doing with the power supply?

 

[adamus]

Very nice! What did you end up doing with the power supply?

Salas shunt, on horrific perfboard as none of the PCBs available fitted. Had to be sinked through the chassis from memory.

 

[L0rdGwyn]

Salas shunt, on horrific perfboard as none of the PCBs available fitted. Had to be sinked through the chassis from memory.

Sounds like a good DIY affair did you find that the heaters lacked a center tap in this amplifier, no virtual center tap either? As far as I can tell, there isn't one, which would explain all of the widely reported hum issues with this amp.

 

[leftside]

Wow, I don’t clean my records like you guys do. I do chuck those paper sleeves and use the mofi sleeves but all I use is a spray with a microfiber brush and one of those gel things for the needle. I am more picky about my digital files and head amps. You guys are on a different level. The occasional pop or click is ok with me but I don’t have a real expensive record player setup either.

One of those "gel things" are good I've had a vinyl setup since I was 7 years old. Been upgrading and tweaking ever since Absolutely love it. Although I do admit DACs have come a long way the last few years, and I now enjoy digital these days for "proper" listening (i.e. darkened room, etc - not just headphones in the gym, listening in the car, etc). We are totally spoilt for choice these days. It's all good.

Given the numerous rabbit holes in this hobby, I am grateful that vinyls is not one I went down.

Head on over to Computer Audiophile.....

 

[adamus]

Sounds like a good DIY affair did you find that the heaters lacked a center tap in this amplifier, no virtual center tap either? As far as I can tell, there isn't one, which would explain all of the widely reported hum issues with this amp. Will dissect it further, but if not that is a big design oversight.

I can't remember if I am honest. I have a feeling I elevated the heaters , but it's probably 10 years ago, and a lot of whisky has been consumed since.

I am currently living my 6e6p parafeed. Would be interested to see more of your gyrator PCB. Any issues with oscillation when Fed with a reg ?

 

[L0rdGwyn]

I can't remember if I am honest. I have a feeling I elevated the heaters , but it's probably 10 years ago, and a lot of whisky has been consumed since.

I am currently living my 6e6p parafeed. Would be interested to see more of your gyrator PCB. Any issues with oscillation when Fed with a reg ?

Ha! Understood, no worries. Yet to be determined on oscillation issues as I have only put together the PCB this morning, but have had no issues feeding cascode CCS in several designs with the reg. Time will tell! Possible it will take a few iterations, might have to add some HF decoupling if oscillation is an issue, fingers crossed.

"Revamped DarkVoice" schematic with the gyrator in place. Reference voltage is generated by cascode LND150 CCS across 220K resistor to ground. Have taken the output from the plate, but could take the mu output as well, depending on how the original owner feels about transistors being in the signal path

 

[adamus]

Nice. I will have a study.

I have been playing with the IXTP08N100D2... In a CCS it sounds better than the dn2540

 

[L0rdGwyn]

Nice. I will have a study.

I have been playing with the IXTP08N100D2... In a CCS it sounds better than the dn2540

I have used the IXTP08N100D2 in cascode with the IXTP08N50D2 with good success, although it was not happy in one of my designs loading a pentode that used NFB, IXCP10M90S in cascode with the DN2540 was more stable in that particular instance...

Thanks for dropping by! Always welcome to come back to talk DIY

 

[Tjj226 Angel]

Ha! Understood, no worries. Yet to be determined on oscillation issues as I have only put together the PCB this morning, but have had no issues feeding cascode CCS in several designs with the reg. Time will tell! Possible it will take a few iterations, might have to add some HF decoupling if oscillation is an issue, fingers crossed.

The gyrator is inspired by Ale Moglia's design, here is a "Revamped DarkVoice" schematic with the gyrator in place. Reference voltage is generated by cascode LND150 CCS across 220K resistor to ground. Have taken the output from the plate, but could take the mu output as well, depending on how the original owner feels about transistors being in the signal path

You can easily ditch the jfet. It wouldn't be a bad idea if you had a gain stage following the gyrator, but a cathode follower will actually dampen the noise of the SS device. Not to mention that the 6080 will be way noisier than any decent mosfet you could throw at the gyrator.

Leave the 2SK170s for the guys trying to build their phonostages

It's also worth pointing out that if you have a CCS on the 6080 cathode, then the gyrator is a bit overkill. I know you were looking at putting a CCS on the 6080, but IDK if you made it that far or not.

 

[L0rdGwyn]

You can easily ditch the jfet. It wouldn't be a bad idea if you had a gain stage following the gyrator, but a cathode follower will actually dampen the noise of the SS device. Not to mention that the 6080 will be way noisier than any decent mosfet you could throw at the gyrator.

Leave the 2SK170s for the guys trying to build their phonostages

It's also worth pointing out that if you have a CCS on the 6080 cathode, then the gyrator is a bit overkill. I know you were looking at putting a CCS on the 6080, but IDK if you made it that far or not.

The 2SK170 is just a stand-in for the sim, I'll be using the J310 on the first go-around. Part of this is to experiment with this design for future use, perhaps replacing the CCS loads in my phono stage I decided to leave the 6080 cathode resistively loaded, there isn't enough space in the DarkVoice for two gyrator boards and a heat-sinked current sink dissipating 8-10W, its too damn hot!

 

[Tjj226 Angel]

The 2SK170 is just a stand-in for the sim, I'll be using the J310 on the first go-around. Part of this is to experiment with this design for future use, perhaps replacing the CCS loads in my phono stage I decided to leave the 6080 cathode resistively loaded, there isn't enough space in the DarkVoice for two gyrator boards and a heat-sinked current sink dissipating 8-10W, its too damn hot!

Just put a CCS in series with the cathode resistor.

Lets say that the 6080 cathode is at 100v at 100ma and your cathode resistor is 1000 ohms. If you don't want a CCS to deal with 10W, what you can do is split the job up between your CCS and cathode resistor.

You drop your cathode resistor down to 500 ohms and you add a CCS at 100ma in series with the resistor. Now the CCS only has to drop 50v which means you have a dissipation of 5 watts.

You can obviously adjust the cathode resistor and CCS values to reduce the heat on the CCS as much as possible. I would probably let the resistor handle 80% of the power and the CCS handle 20%.

That way you actually get some current regulation on the 6080 AND you get the high impedance from the CCS in the cathode.

 

[JazzVinyl]

One of those "gel things" are good I've had a vinyl setup since I was 7 years old. Been upgrading and tweaking ever since Absolutely love it. Although I do admit DACs have come a long way the last few years, and I now enjoy digital these days for "proper" listening (i.e. darkened room, etc - not just headphones in the gym, listening in the car, etc). We are totally spoilt for choice these days. It's all good.

Amen. Been with vinyl a long long time, too. As painful as it is to do, a very carefully aligned cartridge goes a long way towards eliminating surface noise.

I clean 'bought used' records that are really dirty....with wood glue. It's slow, it's messy, and no one believes that it works...but once you figure out how to do it right, makes all other methods seem like a waste of time. If wood glue does not restore the vinyl, it has physical damage and there is no hope of saving it.

And agree about a darkened room! Removing other sensory stimuli is very important in getting the most out of what your listening to.

Also agree that DAC's have come a long way! That is sounding superb these days, too.

But, if your like me and have tons and tons of beloved vinyls' that you like to "study"....

Cheers, all!

 

[L0rdGwyn]

Apparently my fancy deionized water was destroyed in transit, so I will not be receiving it LOL. Guess it will be the bargain buck distilled water then, not going to delay getting the ultrasonic cleaner up and running this weekend.

Hey @bcowen , what kind of filter are you using in your filtration system? I grabbed some of these Pentek CBC-5 0.5 micron carbon filters.

https://www.filtersfast.com/Pentek-...o1DuJD-c3qWfMFipNnBkPenNy88qA91MaAhuUEALw_wcB

 

[bcowen]

Apparently my fancy deionized water was destroyed in transit, so I will not be receiving it LOL. Guess it will be the bargain buck distilled water then, not going to delay getting the ultrasonic cleaner up and running this weekend.

Hey @bcowen , what kind of filter are you using in your filtration system? I grabbed some of these Pentek CBC-5 0.5 micron carbon filters.

https://www.filtersfast.com/Pentek-...o1DuJD-c3qWfMFipNnBkPenNy88qA91MaAhuUEALw_wcB

You just had to one-up me, didn't you? That's a 0.5 micron filter.....I'm using a 1 micron filter:

https://www.amazon.com/gp/product/B00D049XFQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Using this housing for it:

https://www.amazon.com/gp/product/B0014C5D64/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[L0rdGwyn]

You just had to one-up me, didn't you? That's a 0.5 micron filter.....I'm using a 1 micron filter:

https://www.amazon.com/gp/product/B00D049XFQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Using this housing for it:

https://www.amazon.com/gp/product/B0014C5D64/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Well yeah, obviously! If you were using a 0.5 micron filter, I would buy a 0.35

My cleaning solution is just going to be distilled water and Ilfotol. Trying to figure out is if I will run into issues with adsorption of the wetting agent if using a carbon filter. I suspect no, but digging for definitive answers. Any idea?