EL84 Parallel SE Integrated amp

[Soulman]

DIY SE EL84 amp - bought from Alan (Firebottle), I replaced the volume pot with a Blue Alps but other than that the 5W per channel has provided wonderful, room filling music with that distinctive bass attack EL84 amps have. It has 2 inputs and being a parallel design can work with only one EL84 in each side so music keeps playing if one EL84 fails! The amp was totally reworked by Alan before I bought it and I think is exceptional value if you have suitable speakers. I can't fault it and I'm only getting rid to try something else. £220 collected from Sheffield

https://farm2.staticflickr.com/1767/42611544285_0a16590bdd_k.jpg (https://flic.kr/p/27Vriy2)

[Lawrence001]

Hi Des what make of EL84s are fitted, also what are the driver/pre valves? Do you have a list of mods by Alan please?
Thanks, Lawrence

[Firebottle]

The circuit is quite simple, KISS principle, Choke filtered HT, Aikido style driver stage using ECC83, polypropylene coupling capacitors.

[Lawrence001]

The circuit is quite simple, KISS principle, Choke filtered HT, Aikido style driver stage using ECC83, polypropylene coupling capacitors.Thanks Alan did you make it from scratch, I might have got confused as someone was selling a Chinese(?) kit amp that you had "breathed on" recently, is this one your bottom up design?

Sent from my BLN-L21 using Tapatalk

[Firebottle]

There wasn't a lot of the Chinese amp to start with really, it was built for 8 pin octal valves which I didn't have.
So really the only things used were the chassis, input and output connectors, output transformers and the volume pot which has been replaced.

The mains transformer had to be bought so it is a true 240V operation, also with an additional heater transformer for the output valves.

[Soulman]

Thanks Alan, no interest in a great sounding amp?

[Lawrence001]

Sorry I didn't get back, I decided my speakers weren't sensitive enough, but with the right ones I think this would be a little gem.

[Soulman]

It wasn't aimed at you Lawrence just a general question, you're right though it is a gem, I might keep it and swap between this and the Audiosector chipamp kit I'm in the process of building.

[Lawrence001]

No didn't think it was, just wanted to make sure you knew. I bought the Audioromy on the Wam in the end 30wpc but no Firebottle magic :) also probably a 220v transformer :doh:

Sent from my BLN-L21 using Tapatalk

[Pepperamip]

I would love to try this amp in my system but being a southerner just don't work here. Gutted.

Sent from my SM-G930F using Tapatalk

[Clive]

Hi Des, I'm interested.....I too would use it with OB Bastanis, which are similarly sensitive to your Wildhorns. Is the amp pretty much silent into your Wildhorns? Except when music is playing!

Maybe a question more for Alan, are the OPTs 8R only? My speakers are 16R but I expect the 8R OPTs (if that's what they are) should be ok.

[Firebottle]

Yes the O/P transformers are single winding secondary.

[Clive]

Yes the O/P transformers are single winding secondary.

Thanks Alan. Can you estimate the gain/sensitivity? ie 0.775 to 1V approx? I'd use it a power amp either with the volume set to max or with the pot replaced with a suitable resistor.
Any comment on how quite the hum level, if there is any? AC or DC heaters?

[Soulman]

No hum that I've noticed, bit of a crackle when turned off. Not sure on the gain, plenty loud enough at 12 o clock on the volume knob using a line source (dddac1794 or cd player) and too loud by 2 o clock for our 28' by 14' room

[Firebottle]

Looking at the details of a previous build I would say the sensitivity is around 330mV.
Hum is an anathema to me so there is next to no hum.

The heaters are AC, DC heaters are not necessary on a power amp IMO.

[Pepperamip]

Des, do you ever travel south for any reason? I know it's a long shot but I had to ask

[Lawrence001]

PM sent (about something else)

Sent from my BLN-L21 using Tapatalk