Hi,
yes, your guess is correct. Problem with the NFB control is: initially I had the idea to use fixed NFB, set once to my needs with fixed resistor, however later I decided to go with the pot (so I can find the best setting in listening sessions). That time the front panel was already ordered and in production, so I couldn't put it to there anymore. So the setting is now "semi-fixed" because the pot is not reachable anymore (unless I pull the chassis out of the cabinet). If I rebuild this thing one day I will change that. And yes, "loudness" is the tone control (as it provides rouhly "something" like loudness correction). I rarely use full tone control stacks so I omitted it, but need (and want) some compensation especially for low voumes. And that's what it is 🙂
(😡 I had written a novel about the duckie, pilot light and the next project when the Silverfox collapsed, se here we go again.)
The Yellow Duck bought from an on-line toy shop for adults. It is a 😏 to enthusiasts spending more on "sound-enhancing" stuff than on amps, speakers and records. This yellow sound-enhancing is a Quackti, muffled and properly ball-gagged to keep unwanted noise out.
I love lights, so stuffing leds underneath a tube is always cool. A red or orange led enhance the lights emitted from the read-hot chili pepp ... heaters, I mean. A big and green pilot light isn't as bad as a BIG BLUE pilot light, which is what I woudl normally prefer - "blått är flott" (Swedish expression meaning "blue is fancy"). And that brings me to my next project ...
This one has been a shelf-warmer (also from a Swedish expression about stuff that stays (too) long time on the shelf, mostly referred to as stuff in shops), though safely stored under my bed. I is supposed to become a battery-operated 12B4A SE-amp. I found a HV DC/DC SMPS on eBay that will run un 12V and supply like 270V to the tubes (12B4A + 12AT7). The design is a mystery. Looking at the components I guess it may be based on a Darling and probably picked up on a Darling site showing how to double the OP power by replacing the 1626 with a 12B4A.
I have a 40Ah 12V lead battery to power this one.
The pilot light is a 10mm BLUE led.😎
The Yellow Duck bought from an on-line toy shop for adults. It is a 😏 to enthusiasts spending more on "sound-enhancing" stuff than on amps, speakers and records. This yellow sound-enhancing is a Quackti, muffled and properly ball-gagged to keep unwanted noise out.
I love lights, so stuffing leds underneath a tube is always cool. A red or orange led enhance the lights emitted from the read-hot chili pepp ... heaters, I mean. A big and green pilot light isn't as bad as a BIG BLUE pilot light, which is what I woudl normally prefer - "blått är flott" (Swedish expression meaning "blue is fancy"). And that brings me to my next project ...
This one has been a shelf-warmer (also from a Swedish expression about stuff that stays (too) long time on the shelf, mostly referred to as stuff in shops), though safely stored under my bed. I is supposed to become a battery-operated 12B4A SE-amp. I found a HV DC/DC SMPS on eBay that will run un 12V and supply like 270V to the tubes (12B4A + 12AT7). The design is a mystery. Looking at the components I guess it may be based on a Darling and probably picked up on a Darling site showing how to double the OP power by replacing the 1626 with a 12B4A.
I have a 40Ah 12V lead battery to power this one.
The pilot light is a 10mm BLUE led.😎
Attachments
Hey, recently I've finished my upgraded version of OTL headamp. Very tweaked (I think 6th?) version to incorporate big foil output caps and 6N6P tubes. Includes regulated high voltage psu, current regulated series filament psu, full DC protection with turn on delay + status signalling. Contains not only phones output, but also line-out at rear panel to feed power amp + remote turn on +12V signal.
It is very small and fully covered for safe operation, managed to fit it into 22x19x9cm
measurement 1Vrms@250R:
internals:
Very smart 🙂
Being slightly OCD.. the front power switch with the unshielded headphone jack underneath screams out - possibly a power relay and filter on the mains cable?
I think I may just fit one channel's torrids into that box!
Beautiful work Bas:
it seems you have developed a style theme.
Very nice indeed.
it seems you have developed a style theme.
Very nice indeed.
Thanks Scott. It will be the end of an era. Since that hammerite color is no more. But I'll still use the ral1015 color/anodized aluminium/bamboo/oak in the future. 🙂
I too love the hammertoe look ;-). the stuff I can get a hold of is more blue... but it goes well with the mercury vapor diodes 🙂
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I really love the look of your vertical chassis design! It’s a great departure from the usually formats.
Looks good! Simple but effective.
Have but one major opinion (apart from "looks good"). You have a toggle switch to switch between the two inputs on the LH amp - I'd deffunittly picked a rotary switch just because .... knobs for rotary switches ARE COOL!
I just got a qustion from Martha Greenbrook in Little Vallyhill, Sweden: How are the tubes mounted? Du you have a PCB or a subchassi?
Have but one major opinion (apart from "looks good"). You have a toggle switch to switch between the two inputs on the LH amp - I'd deffunittly picked a rotary switch just because .... knobs for rotary switches ARE COOL!
I just got a qustion from Martha Greenbrook in Little Vallyhill, Sweden: How are the tubes mounted? Du you have a PCB or a subchassi?
In the zen clone the tubes are mounted on a pcb. And on the Salas 6v6 on a subchassis.
😀 a reference to the diymag I used to do? Or?
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My latest one is also mounted on a PCB and I have three more PCBs laying around and needing chassis to be completed - maybe time to join a woodworking class.
The one closest to be finished is a GU50-SE, next a 6L6-PP and a 6L6/EL34/GU-SE. PCBs bought from eBay and AliExpress.
Having the tubes, some transformers, bying a 10-20 dollar PCB is an effective way to get your boat in he lake.
Regret that I never designed PCBs for a Luxman-clone. Had I done that I had had some 25-30W of pure triode pushpull power.
"Martha Greenbrook in Little Vallyhill, Sweden." Marta's real coordinates would be Märta Grönbäck, in Dalberg, Sweden.
I do not want to be the asking stoopid question so I let a fellow Swede (imaginary of corse) do it instead. There have been talk shows on Swedish TV where the audience also have gotten a chance to ask questions, so I have picked up that idea.
What DIY mag????? (Uiterst nieuwsgierig)
The one closest to be finished is a GU50-SE, next a 6L6-PP and a 6L6/EL34/GU-SE. PCBs bought from eBay and AliExpress.
Having the tubes, some transformers, bying a 10-20 dollar PCB is an effective way to get your boat in he lake.
Regret that I never designed PCBs for a Luxman-clone. Had I done that I had had some 25-30W of pure triode pushpull power.
"Martha Greenbrook in Little Vallyhill, Sweden." Marta's real coordinates would be Märta Grönbäck, in Dalberg, Sweden.
I do not want to be the asking stoopid question so I let a fellow Swede (imaginary of corse) do it instead. There have been talk shows on Swedish TV where the audience also have gotten a chance to ask questions, so I have picked up that idea.
What DIY mag????? (Uiterst nieuwsgierig)
Jdg123
My friend Rick would like to purchase your amp but has screwed up his diy account. Would you please email Rick dustychi1@gmail.com. He is a member of the Chicago Audio Society.
Thank you for your consideration. Jim
My friend Rick would like to purchase your amp but has screwed up his diy account. Would you please email Rick dustychi1@gmail.com. He is a member of the Chicago Audio Society.
Thank you for your consideration. Jim
I'll see if I can dig them up. These chassis are cheap bamboo boxes. I just order an aluminium plate that fits.. Et voila!
Your dutch is excellent! https://basaudio.wordpress.com/2023/03/25/diyaudiomag-2005/ 2005 - fourth quarter. Subsequent editions can be found on basaudio.wordpress.com as well...(soon)
