Finished the Millett low-mu 6AS7 preamp. Mostly parts I had lying around, the power transformer is for a 50w Marshall so the PS is my own concoction and most of the parts came from my box(es) of spares. It sounds very nice, a tiny touch warmer then the KT88 amp alone. The gain is only around 2, but there's plenty of drive. The CCS current is 63mA so I'll probably take it down to around 50.
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No hum that I’ve noticed with the Svetlana 6H13C. I filtered the heck out of the B+ with 700uF capacitance in total, the PSUD model shows 0.6mV ripple. I also kept any signal as far away from the heater wiring as possible. I going to try a couple of 6080s that I have to see if there’s any tonal difference.
PT8 preamp (Mu-stage)
Currently up-and-running my new tube preamp.
Made on the chassis of my former EL82 power-amps (power supply remained the same; but extended).
It is a Kimmel/Mu-stage with a Philips MRO PT8 triode as the voltage amplifier and an Amperex 8608 as the penthode "on top".
The PT8 is not easily sourced for sane money but other DHT's with a 4V/0,25A filament will work just as good: WE101L, Standard Electric 4019A, STC 3A/107A, Philips TC03/5, etc.
The 8608 is nothing more/less then a E55L with top-connection anode.
The volume control is made from step attenuators sourced from Rohde & Schwarz measuring equipment. Each channel has 2 attenuators: one with 6 x 10 dB steps and one with 9 x 1 dB and 5 x 0,2 dB steps. More then enough options.
The chassis is in essence 2 boxes connected with a hollow pipe. In the power supply part the AC is taken care for; the audio part only sees DC.
Great sounding but a very long warm up time.
The PT8's do sound great and currently the 4019's are running in. Also very nice.
For the TC03/5's i need a convertor socket but that will come in time.
Happy with the result.
Currently pondering on an active loudspeaker system so i can make better use of my power amp projects…….
Regards,
Reinout
Currently up-and-running my new tube preamp.
Made on the chassis of my former EL82 power-amps (power supply remained the same; but extended).
It is a Kimmel/Mu-stage with a Philips MRO PT8 triode as the voltage amplifier and an Amperex 8608 as the penthode "on top".
The PT8 is not easily sourced for sane money but other DHT's with a 4V/0,25A filament will work just as good: WE101L, Standard Electric 4019A, STC 3A/107A, Philips TC03/5, etc.
The 8608 is nothing more/less then a E55L with top-connection anode.
The volume control is made from step attenuators sourced from Rohde & Schwarz measuring equipment. Each channel has 2 attenuators: one with 6 x 10 dB steps and one with 9 x 1 dB and 5 x 0,2 dB steps. More then enough options.
The chassis is in essence 2 boxes connected with a hollow pipe. In the power supply part the AC is taken care for; the audio part only sees DC.
Great sounding but a very long warm up time.
The PT8's do sound great and currently the 4019's are running in. Also very nice.
For the TC03/5's i need a convertor socket but that will come in time.
Happy with the result.
Currently pondering on an active loudspeaker system so i can make better use of my power amp projects…….
Regards,
Reinout
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Good afternoon Kissabout2002,
EXACTLY why i can choose other 4V/0,25A triodes as wel. The PT8 became unfriendly priced after other audio-projects. The WE101L was never cheap as it is "Western Electric" and therefore sought after. Luckily there are still 4019A's, 3A/107A's, TC03/5's and others which can be obtained for acceptable prices.
Besides that i made optimal use of earlier projects so i re-used components.
The turntable you're asking for is my air bearing / air levelled Caeles. I added text and photo's here at DIYaudio (Caeles-special; an air-bearing turntable )
Like all self built audio never finished……
Last months been busy with a vacuüm platter which works out nice.
Regards, Reinout
EXACTLY why i can choose other 4V/0,25A triodes as wel. The PT8 became unfriendly priced after other audio-projects. The WE101L was never cheap as it is "Western Electric" and therefore sought after. Luckily there are still 4019A's, 3A/107A's, TC03/5's and others which can be obtained for acceptable prices.
Besides that i made optimal use of earlier projects so i re-used components.
The turntable you're asking for is my air bearing / air levelled Caeles. I added text and photo's here at DIYaudio (Caeles-special; an air-bearing turntable )
Like all self built audio never finished……
Last months been busy with a vacuüm platter which works out nice.
Regards, Reinout
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This air-bearing turntable is really incredible, the only negative thing is you need a room just for it and the price for sure very hight, did you ever heard about the Mad-Lev levitating turntable? They use magnetism and size is like a normal turntable....but anyway congrats for your turntable is really impressive.
Dear Cbueche,
i'm aware of the WAF but....
1. i was involved in audio long time before i met my girlfriend (now my wife). She knows that audio is "part of me" and accepts that !
2. that turntable seems large BUT was a trade. I had a serious large tube amplifier (see in this forum under TB3/1000 or 833A) weighing in at 400 kgs. THAT was accepted but it ran on 1400 volts and had open copper anode connectors. My wife was not fond of that detail because we had a small kid around. So when the opportunity arised during ETF (European Triode Festival) and someone really liked the big amp i did a swap for the large turntable. In weight almost the same……
Picture included of my old set with my former oversized 50 cm turntable and self built 17" tonearm and the large amps (2 monoblocks with external power supplies). As parts of the rack were empty now i could salvage those to make a table for the external motorhousing, battery powered power supply and vacuum motor for the vacuum platter).
Regards,
Reinout
i'm aware of the WAF but....
1. i was involved in audio long time before i met my girlfriend (now my wife). She knows that audio is "part of me" and accepts that !
2. that turntable seems large BUT was a trade. I had a serious large tube amplifier (see in this forum under TB3/1000 or 833A) weighing in at 400 kgs. THAT was accepted but it ran on 1400 volts and had open copper anode connectors. My wife was not fond of that detail because we had a small kid around. So when the opportunity arised during ETF (European Triode Festival) and someone really liked the big amp i did a swap for the large turntable. In weight almost the same……
Picture included of my old set with my former oversized 50 cm turntable and self built 17" tonearm and the large amps (2 monoblocks with external power supplies). As parts of the rack were empty now i could salvage those to make a table for the external motorhousing, battery powered power supply and vacuum motor for the vacuum platter).
Regards,
Reinout
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Impressive setup after downsizing. Yes, marrying means less space for stuff, or move stuff down to the man's cave. That's what happened to my new table saw, immediately went downstairs so it was never in way of the boss 
On the other hand I already had my 9m carbon mast in the living room for doing some epoxy fix in the winter, so my boss is on the tolerant side... if it's out by next morning
On the other hand I already had my 9m carbon mast in the living room for doing some epoxy fix in the winter, so my boss is on the tolerant side... if it's out by next morning
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Hi Reinout,
What is your speaker drivers and do you have cabinet plan ? As your opinion what kind of musics are more compatible for it ?
Good morning DJN and Alchamist,
these speakers use the following units:
- Fertin 38EX (field coil) for bas (crossover at 230 Hz).
- Feastrex D9NF for 230 Hz upwards.
I made these in 2012 and described them on this forum: FAST / WAW with Feastrex D9NF and Fertin 38EX
If you have more questions on them please make use of the link otherwise we are "polluting" this tube-thread with speaker-stuff....
Great units. Not produced anymore so happy to have them.
Regards, Reinout
these speakers use the following units:
- Fertin 38EX (field coil) for bas (crossover at 230 Hz).
- Feastrex D9NF for 230 Hz upwards.
I made these in 2012 and described them on this forum: FAST / WAW with Feastrex D9NF and Fertin 38EX
If you have more questions on them please make use of the link otherwise we are "polluting" this tube-thread with speaker-stuff....
Great units. Not produced anymore so happy to have them.
Regards, Reinout
![20200522_115646[1].jpg](/community/data/attachments/759/759617-2adb164663b58bce00bda6a5f08d347f.jpg)
One of the marks of summer... The SPL of the A/Cs outweigh the better sound of the tube amps, and heat is the enemy for the next few months...
One of two units in the two windows in my tiny apartment.
This means except for short runs, tube power amps are out for the time being...
The Mighty Yorkville AP1200 to the rescue! lmao
This picture tells me I need to dust.
One of two units in the two windows in my tiny apartment.
This means except for short runs, tube power amps are out for the time being...
The Mighty Yorkville AP1200 to the rescue! lmao
This picture tells me I need to dust.
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