...the truth will out...
Hi John,
I'm not surprised...
I don't like the valve Williamson...the thought of an early transistor one makes me shudder...
Perhaps I should state that I don't like the valve Williamson compared to good push pull designs... it's better than a lot of designs out there...
I recommend a good ECL82 amp for your workshop (to get back on topic
)
Finished your 845 yet.)
ciao
James
Hi John,
I'm not surprised...
I don't like the valve Williamson...the thought of an early transistor one makes me shudder...
Perhaps I should state that I don't like the valve Williamson compared to good push pull designs... it's better than a lot of designs out there...
I recommend a good ECL82 amp for your workshop (to get back on topic
)Finished your 845 yet.)
ciao
James
Re: ...the truth will out...
My workshop speakers don't seem very efficient - must check...
The 845 is coming on Still doing the PSU metalwork. I am one to set myself hard tasks (6mm ally).
Once I've done this, it's off down to the anodisers, a reassemble and test!
Cheers,
ECL82? Maybe in PPJames D. said:Hi John,
I'm not surprised...
I don't like the valve Williamson...the thought of an early transistor one makes me shudder...
Perhaps I should state that I don't like the valve Williamson compared to good push pull designs... it's better than a lot of designs out there...
I recommend a good ECL82 amp for your workshop (to get back on topic
Finished your 845 yet.)
ciao
James
My workshop speakers don't seem very efficient - must check...The 845 is coming on
Still doing the PSU metalwork. I am one to set myself hard tasks (6mm ally). Once I've done this, it's off down to the anodisers, a reassemble and test!
Cheers,
EC8010
I had a Cadet III in daily use until 7 years ago when I sold it to my neighbour. He used it in his study and loved it - said he relaxed listening to music through the Cadet whilst his main system was very impressive it didn't let him (or me ) relax. His main system was powered by a big Krell...
The ECL86 is a lovely valve too.
I can get PCL82s for euro 3:50 each! Works for me....
BTW has anybody got triode curves for ECL82/PCL82/UCL82???
ciao
James
I had a Cadet III in daily use until 7 years ago when I sold it to my neighbour. He used it in his study and loved it - said he relaxed listening to music through the Cadet whilst his main system was very impressive it didn't let him (or me ) relax. His main system was powered by a big Krell...
The ECL86 is a lovely valve too.
I can get PCL82s for euro 3:50 each! Works for me....
BTW has anybody got triode curves for ECL82/PCL82/UCL82???
ciao
James
Yesterday I got a bit bored while waiting for Santa Claus to arrive with new Mosfets for my class a amp, so I started up a project that I´ve planned for quite some time: The world´s smallest tube amp!! Ok, it may not be the worlds smallest, but I tell you it´s small!
The chassis measure 175 x 97 x 32 mm and holds (so far) two ECL82:s, two really tiny output trannies, one power tranny, one 25+25µF cap plus input/output connectors and a powerswitch.
I think there´s room for a volume pot too, but I´m not sure.
Onthe picture you see the results of four hours of work done late
last night, all that´s left now is the caps and resistors inside.
The chassis measure 175 x 97 x 32 mm and holds (so far) two ECL82:s, two really tiny output trannies, one power tranny, one 25+25µF cap plus input/output connectors and a powerswitch.
I think there´s room for a volume pot too, but I´m not sure.
Onthe picture you see the results of four hours of work done late
last night, all that´s left now is the caps and resistors inside.
Attachments
Fuling said:
My 5-Buck Amp is almost expansive by comparison at 226x102x44 mm.
An externally hosted image should be here but it was not working when we last tested it.
dave
Hello. I am new at this forum, and I feel very happy to find all this thermoionic friends here.
I have bought an amplifier at e-bay. The brand is Majestic, model 189. It was made in Barcelona (Spain) in 1960. It is a pp with two Mullard ECL82 per channel, EZ81 rectifier, and I am still not able to see the two pre-amp valves, because they are inside a metal cover and the screws are a little bit rusted.
I love the sound, more than my pp with EL34, but it needs some improvements. Both channels don't sound exactly the same, and it have a little hum when the volume is turned up, so I am going to workout the schematics, change all the capacitors, and I will think if I will get rid of the tone control.
Actually, I don't know why some purists satanize the tone controls (just move your ears a little bit with your fingers in front of your speakers, and the tone you hear will change completely), so maybe I will try to install a bypass switch at the tone circuit just to workout the difference.
I will publish the schematic as soon as I draw it.
Cheers,
I have bought an amplifier at e-bay. The brand is Majestic, model 189. It was made in Barcelona (Spain) in 1960. It is a pp with two Mullard ECL82 per channel, EZ81 rectifier, and I am still not able to see the two pre-amp valves, because they are inside a metal cover and the screws are a little bit rusted.
I love the sound, more than my pp with EL34, but it needs some improvements. Both channels don't sound exactly the same, and it have a little hum when the volume is turned up, so I am going to workout the schematics, change all the capacitors, and I will think if I will get rid of the tone control.
Actually, I don't know why some purists satanize the tone controls (just move your ears a little bit with your fingers in front of your speakers, and the tone you hear will change completely), so maybe I will try to install a bypass switch at the tone circuit just to workout the difference.
I will publish the schematic as soon as I draw it.
Cheers,
Attachments
Majestic 189 ECL82 Power Stage Schematic
Here is the schematic of the Power Stage ¿any sugestions?
Now I am working the sketch of the pre-amp, and I find that the ECC83 share 1/2 valve for each of the two stereo channels. I mean, the two channels are not separately on two valves but they use one triode of the same valve. That means that maybe the channel separation will suffer. ¿What do you think? ¿Is it usual to mix channels inside the same valve?
Here is the schematic of the Power Stage ¿any sugestions?
Now I am working the sketch of the pre-amp, and I find that the ECC83 share 1/2 valve for each of the two stereo channels. I mean, the two channels are not separately on two valves but they use one triode of the same valve. That means that maybe the channel separation will suffer. ¿What do you think? ¿Is it usual to mix channels inside the same valve?
Attachments
Majestic 189 ECL82 Pre-amp Schematic
Ok, and here is the pre-amp and tone control section of this pretty oldie. ¿Do you have some better circuit to replace the whole thing?. I don't like the idea of using the triodes of the same valve (V1a and V2b) for the different stereo channels.
Ok, and here is the pre-amp and tone control section of this pretty oldie. ¿Do you have some better circuit to replace the whole thing?. I don't like the idea of using the triodes of the same valve (V1a and V2b) for the different stereo channels.
Attachments
Don't be afraid of using both triode halves for different channels. The channel seperation won't suffer much from it, in fact the sharing of the same powersupply has got a much bigger influence. You probably won't hear any difference at all when switching to one tube per channel. Using one tube for both channels has got one big advantage; you don't have to match the tubes between left an right, so the advantage might be a lot bigger than the disadvantage.
The power amplifier:
The input triode is missing its grid leak resistor.
The 47 ohm feedback resistor has to be wrong, check again
Maybe increase the coupling capacitors to the pentodes to 100 nF or so to better up the bass.
The preamplifier:
In my opinion, ditch it. Use only one ECC82 instead (or better, an E80CC), plate resistor 100k, cathode resistor 2.2k in parallel with 100 uF. Add a 100 nF coupling cap from this tube to the power amplifier and add a 470k gridleak there. Connect a good pot, viper to the ECC82 grid. That's all.
You will have one empty socket left.
Don't be afraid of sharing tube halves between the channels. My own preamplifier has 5 dual triodes from the phono input to output, all of them share the channels. No problem.
The input triode is missing its grid leak resistor.
The 47 ohm feedback resistor has to be wrong, check again
Maybe increase the coupling capacitors to the pentodes to 100 nF or so to better up the bass.
The preamplifier:
In my opinion, ditch it. Use only one ECC82 instead (or better, an E80CC), plate resistor 100k, cathode resistor 2.2k in parallel with 100 uF. Add a 100 nF coupling cap from this tube to the power amplifier and add a 470k gridleak there. Connect a good pot, viper to the ECC82 grid. That's all.
You will have one empty socket left.
Don't be afraid of sharing tube halves between the channels. My own preamplifier has 5 dual triodes from the phono input to output, all of them share the channels. No problem.
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