New amp build - EF86, 10w 6L6/EL34 single ended combo (in tweed)

eddy999

Member
Messages
220
I wanted to build a nice simple clean combo to use as a pedal platform - as simple as it comes - power switch, volume. I only play in church and we always mic up the amps - my previous head/cab were overkill and more than i'd like to carry.

The circuit is an EF86 preamp feeding a 6L6GC (or EL34) with a volume pot between the two - doesn't get much simpler than that. I based it on my previous 10w head, although I got rid of the power scaling and added a choke for better filtering without losing voltage (and volume).

The build went surprisingly well considering it has been around 8 months since my last proper project. After all the voltages checked out for the initial power up I popped the tubes in and it worked beautifully. The noise floor is very low, no audible hum and only hiss at higher volumes. I'm very pleased with the lack of hum as my previous single ended amp originally hummed until I added an additional RC filter before the plates - that solution did however lose voltage through the resistor due to the entire amp's current draw feeding through it.. In this version I decided to try a choke with a low resistance before the plate feed - sounds great and the current rating is way above what the amp pulls so it should perform well.

I had the cab built by Chris Uff (A UK cab builder who I found through Ampmaker.com) - he did a great job with the build and turned it around really quickly - highly recommended (chris@c-and-l.freeserve.co.uk).

All I need to do now is mount the chassis in the cab (when my cage nuts arrive in the post that is) and sort out a faceplate.. I don't think i'll go with a laser etched plate this time - I'm going to experiment with some thin real wood veneers to keep the simple look. I used a pre-drilled chassis, hence the extra unused holes on the front panel.

I decided on an Eminence Ragin Cajun for the speaker (10 inch). I haven't tried one before and i'm very pleased with how it sounds so far.

I'm very pleased with how the amp turned out - the EF86 has tons of headroom and takes pedals really well, plus really sings when hit with a nice clean boost (i'm using a TC Spark). I'll add clips soon when I get the time to record them.





















 

tele_jas

Member
Messages
3,720
Hey, Brits aren't supposed to use Tweed..... That's for us Americans! ;)

Just kidding....That's a sweet n simple build (good looking too) and I bet it sounds amazing! Can't wait for the clips.
 

eddy999

Member
Messages
220
A quick clean demo, some reverb and delay in places (from pedals rather than post-prod). More to come later on.

[SOUNDCLOUD]https://soundcloud.com/eddy999-1/10w-combo-clean-demo[/SOUNDCLOUD]
 

PGrant

Member
Messages
1,072
Really cool build. But the guy that built the cab still has a Freeserve email address? LOL!
 

eddy999

Member
Messages
220
Chassis mounted. I've ordered some wood veneer samples that should be big enough to cut into a faceplate - i'm interested to see how they turn out.



 

novel

Member
Messages
71
Nice!

With such a simple circuit, does it in fact stay clean and constant in character all the way up, or does it change with volume and reach breakup at a certain point?

Sounds like a perfect clean amp/pedal platform.
 

eddy999

Member
Messages
220
Nice!

With such a simple circuit, does it in fact stay clean and constant in character all the way up, or does it change with volume and reach breakup at a certain point?

Sounds like a perfect clean amp/pedal platform.
It stays clean and sounds the same nearly all the way, only starting to break up when nearly cranked. It seems with an instrument level signal my preamp only just has enough juice to start pushing the 6L6GC into overdrive (and sounds great doing it). When hit with a clean boost like the TC Spark however it is a different story and it breaks up much sooner (and is a fair bit louder too).

As a clean platform for mic'ing there's plenty of clean headroom before it starts to distort which should suit my needs perfectly.
 

zzmoore

Member
Messages
7,095
No it was R13 I swapped out for the choke, and I left out the B+ fuse and VVR also this time.
It's funny, when I first started Reading/Hearing about Variable Voltage Regulation...I could never understand the acronym.
I always that people were typing
WR
which looks so much like
VVR
when it is all said and done..... ;) :)
 

eddy999

Member
Messages
220
It's funny, when I first started Reading/Hearing about Variable Voltage Regulation...I could never understand the acronym.
I always that people were typing
WR
which looks so much like
VVR
when it is all said and done..... ;) :)
Yes I find that the Wariable Roltage works really well on the whole, just not necessary in this build. :)
 




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