Successfully finished my JE LABS 2A3DX amp, it was so fun that I needed to go on with another project. I decided to build an amp for my pc. Just then I received a surprising present from a colleague whose father was a TV repairer: a bunch of TV tubes: PCC189, PCF80, PCF86, PCL84, PY88 and others. After a search in Internet I decided to build an amp with two PCL84 using the schematic for ECL84 tubes:
http://www.diyaudio.com/forums/attachment.php?attachmentid=67204&d=1152603590
It is a double tube with a triode and a pentode inside, so tjhe whole amp can be made with a single tube.
The only difference between the PCL84 and the ECL84 is the filament voltage (15 V instead of 6,3)
I used Hammond 125ESE OPTs and common components (except the ALPS volume pot, the SOLEN coupling capacitors and MILLS cathode resistors)
I have finished the amp and I am surprised how good sounding it is (I’m not an expert and I hear mainly classic music). No hum, good bass, detailed mids and highs. I am very pleased with it. Here is a pic.
http://www.diyaudio.com/forums/attachment.php?attachmentid=67204&d=1152603590
It is a double tube with a triode and a pentode inside, so tjhe whole amp can be made with a single tube.
The only difference between the PCL84 and the ECL84 is the filament voltage (15 V instead of 6,3)
I used Hammond 125ESE OPTs and common components (except the ALPS volume pot, the SOLEN coupling capacitors and MILLS cathode resistors)
I have finished the amp and I am surprised how good sounding it is (I’m not an expert and I hear mainly classic music). No hum, good bass, detailed mids and highs. I am very pleased with it. Here is a pic.
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Lovely looking amp there 😛
And that they sound nice is great news for me, I have around 40 ECL84's (or 6DX8's). Don't know how many go, or how well, but out of 40 some have got to be okay, right? 😛
And that they sound nice is great news for me, I have around 40 ECL84's (or 6DX8's). Don't know how many go, or how well, but out of 40 some have got to be okay, right? 😛
Thanks derwhalfisch. I only have 8 PCL84, Miniwatt, Tungsram and Mullard. I used 2 Mullard and both work perfectly. Not tried with the rest.
I recently got a box of one hundred NOS, used and unknown 6DX8 tubes from eBay on the cheap.... just trying to figure out which design to work off...
Anode curves for triode-strapped ECL84 / 6DQ8 / 6DX8 / 6Phi4Pi or series heaters variant PCL84 / 15DQ8 here: http://www.tubes.mynetcologne.de/roehren/daten/ecl84pentode_as_triode.pdf
Regards,
Tom Schlangen
Regards,
Tom Schlangen
Hiya 🙂
How do you pick what type of speaker transformer to use??? Sorry about my spelling if its wrong.
I am useing a 14 ohm speaker on a small 5 watt RS universal "what is say" specer transformer but it's only seems to be giving the speaker about 500mW of power at full volume from the valve 🙁
I used this plan too: http://www.diyaudio.com/forums/attac...4&d=1152603590
How do you pick what type of speaker transformer to use??? Sorry about my spelling if its wrong.
I am useing a 14 ohm speaker on a small 5 watt RS universal "what is say" specer transformer but it's only seems to be giving the speaker about 500mW of power at full volume from the valve 🙁
I used this plan too: http://www.diyaudio.com/forums/attac...4&d=1152603590
Hello,
the pentode is connected as a triode, I wouldn´t expect more than 1W of power. If you need more power, you should consider building a PSE amplifier with at least 2 ecl84 valves per channel or chose a stronger valve.
George
the pentode is connected as a triode, I wouldn´t expect more than 1W of power. If you need more power, you should consider building a PSE amplifier with at least 2 ecl84 valves per channel or chose a stronger valve.
George
🙂How many output in this SE Amp? I have 2 pcs in PCL84. I want to do that this circuit. but my output transfomer only for 5K:8. Thank you for your help.
The PCL84/6DX8 can take a lot of abuse. I've pushed them way beyond rating (9W+!!!) for hundreds of hours in testing without degradation of the performance.
MiniWatt shows them as SE audio amps at Va=250, Ia=16ma, Po=1.65W thd=10% with a 17.5K load.
They also show Va=200V, Ia=20mA, Po=1.65mA, thd=10% with a 11kLoad.
So you need a fairly high impedance load unless you parallel multiple tubes as suggested by revintage.
MiniWatt shows them as SE audio amps at Va=250, Ia=16ma, Po=1.65W thd=10% with a 17.5K load.
They also show Va=200V, Ia=20mA, Po=1.65mA, thd=10% with a 11kLoad.
So you need a fairly high impedance load unless you parallel multiple tubes as suggested by revintage.
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