Very good 6N1P or 6N1P-EV are still available from Russian or Ukrainian sellers on the big auction site for little money. Have bought all my Russian tubes this way.
The more I use this tube, the more I like it
Regards, Claas
P.S.: My very first tube amp design was a headphone amp kit I bought from the small German firm Ampdesign, the KHV-88. The owner has since sold on the business because he finally retired from his retirement-hobby, and the new owners only offer the "kit" with fully stuffed PCBs ... but the schematic is still available on the website ... just search for "Ampdesign KHV-88".
The circuit is similar to kodabmx' design.
Hmm ... if you ask them, they might still sell you a pair of bare PCBs ...
Danke für den Tipp, vielleicht frage ich sie
I think construction is as important as circuit.
This guy built a headphone amp and he knows what he is doing. It may not be a bad idea to just get a PCB from him.
Mission Accomplished and OTL Options
This guy built a headphone amp and he knows what he is doing. It may not be a bad idea to just get a PCB from him.
Mission Accomplished and OTL Options
Have a look at the supply for the Ampdesign KHV-88. It is absolutely noiseless and hum-free in my KHV-88 headphone amp.
I have later adapted the supply schematics for my Aikido preamp as well, modified with a CCS for the voltage-setting Zener string. Works perfectly here also.
Regards, Claas
I have later adapted the supply schematics for my Aikido preamp as well, modified with a CCS for the voltage-setting Zener string. Works perfectly here also.
Regards, Claas
For the circuit I posted in post #2, I use two SMPS...
This one for HV inside the amp chassis: DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay
And this one (12V, 10A) to power it (and the heaters): AC 110V To DC 5V 12V 24V Power Supply Adapter Transformer For LED Strip Lights | eBay
No hum, no hiss.
This one for HV inside the amp chassis: DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay
And this one (12V, 10A) to power it (and the heaters): AC 110V To DC 5V 12V 24V Power Supply Adapter Transformer For LED Strip Lights | eBay
No hum, no hiss.
Just as a note, the little edcor parafeed opt are available in Europe here: Edcor PCW10K-7K/300-32, 23,76 € on sale. Still 24€ a piece but they're nice little transformers.
Just be aware that they easily pick noise from a power transformer. In my build based on the 6e5p, I had to put the xformer in another box to get rid of the last hum.
Just be aware that they easily pick noise from a power transformer. In my build based on the 6e5p, I had to put the xformer in another box to get rid of the last hum.
Hopefully not derailing this thread, but I'm fighting a hum problem right now in my headphone amp. Its a Tubelabs SE amp with 45 DHT's. Looking at shielding the power tx to see if that helps. With the high current required for DHTs, I don't know if putting the tx in another box is a good idea, but maybe I'll try and see what happens.
My low impedance, planar headphones sound fine, tiny bit of hum, more noticeable on my hd800's.
BTW, sounds nice, but not a cheap build, iron adds up.
Randy
Geoff had a hum problem with his headphone amp also.
"Geoff undertook the crazy quest of building my 2P29L HP amp design in a single enclosure! After a lot of tinkering with the grounding layout and physical layout and orientation of transformers and other components, he managed to get it dead quiet. An amazing achievement for a DHT in a single enclosure! After discussing it with him, obviously regretted having done so as it was a big headache which left his metal case with a several holes from moving stuff around."
Headphone Amp Shootout – Bartola(R) Valves
"Geoff undertook the crazy quest of building my 2P29L HP amp design in a single enclosure! After a lot of tinkering with the grounding layout and physical layout and orientation of transformers and other components, he managed to get it dead quiet. An amazing achievement for a DHT in a single enclosure! After discussing it with him, obviously regretted having done so as it was a big headache which left his metal case with a several holes from moving stuff around."
Headphone Amp Shootout – Bartola(R) Valves
Thanks. I saw that, but no pics of the amp so I'm not sure what the final solution was.
Take an iron sheet and just put it between power tranny (or choke) and your output transformer. If you find appreciable lower hum it's a sign the transformers are coupled and should be rotated. If no improvement you should investigate grounding or wire dressing.
It won't help, you need it around. Such a way you can shield capacitive coupling, not magnetic.
I don't think you're ruining this thread, it's always good to be aware of adequate transformator isolation.
Have a look at this (click on the product picture and scroll them through). TTSAS0020 - SUPREME AUDIO grade transformer TSAS20VA - voltage to 50V - Shop Toroidy.pl
Have a look at this (click on the product picture and scroll them through). TTSAS0020 - SUPREME AUDIO grade transformer TSAS20VA - voltage to 50V - Shop Toroidy.pl
Hi
Im Geoff in Ale,s blog. I wanted to use a single chassis for space reasons and I have a few of the cases
available. They were 300mm deep x 250 wide x 70 high. I placed the mains transformers at the rear of the chassis along with the graetz bridge ez80 rectifier. The two valves along with their coleman reg boards and Ale,s mu follower boards were about 2/3 along.
When I got the amp running I got hum as I probably should have expected. I moved the valves right to the front of the case hence the extra holes and tried different oriientation of the transformers plus a belly band around the ht transformer. All this did reduce the level of the hum but did not eradicate it completly.
What did was rewiring the amp to minimise the loop area of signal/return and power/return cables.
Finally I wanted to have the signal i/p sockets at the rear of the case but I didnt do this initially because the transformer for the Coleman regs would be quite near. I placed some mu metal foil shielding between the transformer and the sockets which worked. I could see the reduction using my scope
probe as sniffer.
The amp is absolutely quiet and sounds gorgeous. It drives my Sennheiser HD800,s with ease. I can drive them directly from the mu follower o/p as its o/p impedance is about 30ohms but it needs a big cap so I use a 100uf/500v dc-link polyprop. Ive also tried using a 4 1 step down transformer in parafeed so as I can use a smaller "audiophile" capacitor. The sound is slightly different but I cant make up my mind which I prefer.
Im about to make another one with some 10Y,s because I want to see if thoriated tungsten cathode dht,s are as good as Ale and Andy Evans say they are. I will use the same chassis because if I can make one quiet I hopefully can repeat it.
Hope this is of help.
Im Geoff in Ale,s blog. I wanted to use a single chassis for space reasons and I have a few of the cases
available. They were 300mm deep x 250 wide x 70 high. I placed the mains transformers at the rear of the chassis along with the graetz bridge ez80 rectifier. The two valves along with their coleman reg boards and Ale,s mu follower boards were about 2/3 along.
When I got the amp running I got hum as I probably should have expected. I moved the valves right to the front of the case hence the extra holes and tried different oriientation of the transformers plus a belly band around the ht transformer. All this did reduce the level of the hum but did not eradicate it completly.
What did was rewiring the amp to minimise the loop area of signal/return and power/return cables.
Finally I wanted to have the signal i/p sockets at the rear of the case but I didnt do this initially because the transformer for the Coleman regs would be quite near. I placed some mu metal foil shielding between the transformer and the sockets which worked. I could see the reduction using my scope
probe as sniffer.
The amp is absolutely quiet and sounds gorgeous. It drives my Sennheiser HD800,s with ease. I can drive them directly from the mu follower o/p as its o/p impedance is about 30ohms but it needs a big cap so I use a 100uf/500v dc-link polyprop. Ive also tried using a 4 1 step down transformer in parafeed so as I can use a smaller "audiophile" capacitor. The sound is slightly different but I cant make up my mind which I prefer.
Im about to make another one with some 10Y,s because I want to see if thoriated tungsten cathode dht,s are as good as Ale and Andy Evans say they are. I will use the same chassis because if I can make one quiet I hopefully can repeat it.
Hope this is of help.
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