I've obtained the Mullard Three-Watt amplifier circuit, looking to build it from scratch. Apart from obtaining suitable transformer, valves etc., might there be any recommendations or improvements that i'll need to take on board?
Apologies for not posting (04-07-2022)
Apologies for not posting (04-07-2022)
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Use a triode up front, EL84 does not need much drive.
There are many examples of SE EL84 circuits, we ended up, after many iterations, with a Schade/RH84-like amplifier.
If you don’t want feedback, triode operation.
dave
There are many examples of SE EL84 circuits, we ended up, after many iterations, with a Schade/RH84-like amplifier.
If you don’t want feedback, triode operation.
dave
You might want to consider the LM8/2A version the BBC adopted, it is more conventional being capacitor coupled and not running the EF86 in starvation mode. http://www.bbceng.info/ti/eqpt/AM8_2.pdf It uses the same mains and output transformers.
Not everyone has success with the Mullard 3-3. It can be Very valve dependant.
Not everyone has success with the Mullard 3-3. It can be Very valve dependant.
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The Mullard 3-3 was my first amplifier, a bit over 60 years ago. It was mono and replaced three or four years later with Mullard 5-10's and subsequently 5-20's.
The 3-3 sounded OK but lacked power; its negative positive feedback design works well, but at 3 watts you need efficient speakers and a small room Anyway, have fun.
There is also a 3W amp based on an ECL86, single tube per channel, here:
http://www.r-type.org/articles/art-003g.htm
http://www.r-type.org/articles/art-003g.htm
If you must build a Mullard I would strongly recommend you switch to the 5/20. A three watt amplifier is really very little use.
Everyone has an opinion. The bottom line is does it work well with whatever other equipment is part of the system?
Is it reliable, bullet proof? Here is one that has run in the shop since 1968. Complete with Baxandall tone circuits &
a low level preamp for GE VR magnetic cartridge, switchable to a low level mike.
The sources are an Eico HFT90 FM Tuner & Eico HFT94 AM Tuner. And a CD Deck.
Only the Power amp & Power Supply are shewn on the schematic.
Its been on this forum a few times before, here it is again today. 🙂 👍
Is it reliable, bullet proof? Here is one that has run in the shop since 1968. Complete with Baxandall tone circuits &
a low level preamp for GE VR magnetic cartridge, switchable to a low level mike.
The sources are an Eico HFT90 FM Tuner & Eico HFT94 AM Tuner. And a CD Deck.
Only the Power amp & Power Supply are shewn on the schematic.
Its been on this forum a few times before, here it is again today. 🙂 👍
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Rather than reply to each post, here i give my thanks to all the posters.
I will prefer to stick to the 3 Watt or maybe go for a slightly higher wattage Mullard amplifier.
Peteki, (or anyone else) might you have the Mullard Cct 5-20' ?
I've found the 5-10 Ten Watt amplifier here http://www.r-type.org/articles/art-003e.htm
I will prefer to stick to the 3 Watt or maybe go for a slightly higher wattage Mullard amplifier.
Peteki, (or anyone else) might you have the Mullard Cct 5-20' ?
I've found the 5-10 Ten Watt amplifier here http://www.r-type.org/articles/art-003e.htm
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Prototyped Mullard 5-10 Triode Mode. 5 wpc. (Converted to choke filtered B plus later)
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Audio Amateur Publications reprinted a new copy from the original in1993.
And sold by Glass Audio, AudioXpress & others. I bought a copy about 20 yrs ago.
But nice to have it on a PDF now.
For some who might like a physical copy both new & used are on the market.🙂
Very interesting amplifier. I am not sure I have ever seen a GNF amp without compensation.