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Here is my attempt at building 2 monoblocks, based on the Mullard 5-20, redesigned by Claus Byrith, now called 4-30. Nothing special or fancy about them, except for the blue LED power switch. ;-)

I used Hammond 1645A OPT's and added a switch to choose between 12AX7 or 6N2P (basically the same thing, just different heater connections)

My speakers are Fostex FE207E's and they sound great together.
 

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Bespoke Constructor
Joined 2006
Paid Member
Here is my attempt at building 2 monoblocks, based on the Mullard 5-20, redesigned by Claus Byrith, now called 4-30. Nothing special or fancy about them, except for the blue LED power switch. ;-)

I used Hammond 1645A OPT's and added a switch to choose between 12AX7 or 6N2P (basically the same thing, just different heater connections)

My speakers are Fostex FE207E's and they sound great together.

Nice little project . well done, any chance of a diagram :)
 
JDeV, very nice simple, clean build. Good work.

Thanks for all comments.
My next project is to "upgrade" my 6N3 (5670) pre-amp/buffer by adding a FM tuner, BlueTooth Receiver, SD card reader and USB port to it.

This is as it is now:

It was the Guanzo 6N3 pre-amp to which I applied some of the suggested mods to it, as described here:
http://audiokarma.org/forums/index.php?threads/say-hello-to-my-new-little-friend.306203/page-25

I used 1uF caps for C4/C7 + C6/C9 as 2.2uF produced too much bass.
I also did some mods to the PSU. Installed all AC parts in a separate enclosure, added some more filtering to it as well. Had some annoying ground loop issues, which I resolved.

I adjusted the HT voltage to 155V to be more friendly to the 200V PSU caps, the heaters supply was changed to 6.2V.

Also added a remote controlled volume POT to it.
 

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6L6 build

Some time ago (month or so) I spent the weekend fiddling with the idea of a 6l6 SE amp. Used some spare parts to formulate an idea and an attack plan. For some octal love I decided on a 6SL7 for the single gain stage. The 6l6 could be switched out with a 5881 or with some wiring changes about any of your garden variety power tubes.

Included is the scheme i settled on. I was debating about where to put the volume pot and truthfully, I'm still a little in the air about it. If I moved the volume pot to between the stages I'd test out a treble bleed cap across it as well. The attached is when I was toying with pentode/ultralinear yet, R,s is omitted currently and the screen is wired into the OPT UL tap.

The inner kid in me couldn't help doodling a little bit and i used a sharpie to try and plan out where I waned standoffs and wiring to go. Before final assembly I took a picture for reference and cleaned it all up with some denatured alcohol. It forsure help with visualizing where I wanted to put everything. All said an done I was real happy with how the layout ended up. I tried to make sure I was as tidy as possible, the amp will end up having a plexiglass bottom with some standoffs. Thought it would be a neat-o touch.

These edcors are great. The GSXE series rolls off around 40Hz and my choice of capacitors for bypass put about 6DB around 20Hz as well. It currently has no issue whatsoever down into the 50Hz range but falls off after that. I'd be interested to try some CSXE at some point and recap the bypass to hear the difference. I'll also be testing on some more capable speakers (buddy has some ELAC Uni-fi) to see how my polk monitor 60's stand up. heh...get it? ...floor standing...

Also threw in some pictures of what I listen to on and off. There's a bit of a boost due to the schiit house sound but the mids and lower trebble are just fantastic. Vocals, acoustic, and brass/horns are just sublime. Of course I had to giver-wah with the Zep and I'm actually quite impressed with how clean it stays when I crank it. Overall its a very balanced sound with a slight *ever so slight* mid-scoop. Biased a bit more towards the trebble end maybe but it has no problems providing some tight, punchy bass. For as simple as the circuit is I couldn't be happier with the sound.

Not quite decided on what's next. I started gutting out my HK A500 to try some different topologies and venture into P-P territory. I've also really been itching for a Trainwreck guitar head clone.
 

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Some time ago (month or so) I spent the weekend fiddling with the idea of a 6l6 SE amp. Used some spare parts to formulate an idea and an attack plan. For some octal love I decided on a 6SL7 for the single gain stage. The 6l6 could be switched out with a 5881 or with some wiring changes about any of your garden variety power tubes.

Included is the scheme i settled on. I was debating about where to put the volume pot and truthfully, I'm still a little in the air about it. If I moved the volume pot to between the stages I'd test out a treble bleed cap across it as well. The attached is when I was toying with pentode/ultralinear yet, R,s is omitted currently and the screen is wired into the OPT UL tap.

The inner kid in me couldn't help doodling a little bit and i used a sharpie to try and plan out where I waned standoffs and wiring to go. Before final assembly I took a picture for reference and cleaned it all up with some denatured alcohol. It forsure help with visualizing where I wanted to put everything. All said an done I was real happy with how the layout ended up. I tried to make sure I was as tidy as possible, the amp will end up having a plexiglass bottom with some standoffs. Thought it would be a neat-o touch.

These edcors are great. The GSXE series rolls off around 40Hz and my choice of capacitors for bypass put about 6DB around 20Hz as well. It currently has no issue whatsoever down into the 50Hz range but falls off after that. I'd be interested to try some CSXE at some point and recap the bypass to hear the difference. I'll also be testing on some more capable speakers (buddy has some ELAC Uni-fi) to see how my polk monitor 60's stand up. heh...get it? ...floor standing...

Also threw in some pictures of what I listen to on and off. There's a bit of a boost due to the schiit house sound but the mids and lower trebble are just fantastic. Vocals, acoustic, and brass/horns are just sublime. Of course I had to giver-wah with the Zep and I'm actually quite impressed with how clean it stays when I crank it. Overall its a very balanced sound with a slight *ever so slight* mid-scoop. Biased a bit more towards the trebble end maybe but it has no problems providing some tight, punchy bass. For as simple as the circuit is I couldn't be happier with the sound.

Not quite decided on what's next. I started gutting out my HK A500 to try some different topologies and venture into P-P territory. I've also really been itching for a Trainwreck guitar head clone.

retro-thermionic: "Silver Supreme" - 6L6 SE UL amp in a wooden box
retro-thermionic: 6L6 SE UL power amp in a wine bottle box

Only recently built a couple of 6L6/12AT7 power amps myself. These are built in a $9 wine gift box. One stained and varnished. They use a universal external tranni box but have there own rectifier and filter ccts. The tubes are JJ 6L6 GC and Psvane 12AT7 "T" series MKII and in the blonde box JAN 6L6s (1944) and Miniwatt 12AU7. Again with its own rectifier and filter.

I'm absolutely stunned how good the tube is in this SE UL build. I had a forum friend design the amp for me (and my last 12 tube amps) and he did a great job as usual. The schematic is free for private use.

On the CRO mine go down to 50hZ (-3db point) and only produce 2W but on my 99db efficient 15" concentric Beymas play way to loud with no clipping. Bass feels good down to 40hZ easy with room reenforcement. I have found a number of friends have commented how fast the amp is and a guy only yesterday said he thought he was listening to a SS amp its that quick.

I'm playing the amp while typing this. What a great and cheap tube.
 

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Hi there

my latest project is are these two single-ended tube / BJT hybrid amps with a KT66 as a cathode follower driving a 2SC5200 BJT with is cascoded by an IXFN32N120. The latter one is attached to a 0.4K/W heatsink to dissipate around 80W power loss. Local feedback is applied from the primary coil of an LL1693 output transformer into the KT66 screen grid. Output power is 24W. Schematics and a detailed description can be found @ http://www.diyaudio.com/forums/tubes-valves/284711-supertriode-bjt-mosfet-good-idea-3.html

Regards

KlausB
 

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Hi Bill,

well, of course my statement is not free from subjective bias, but I am truly very happy with the performance. The soundstage is really good. There is an excellent downward dynamic resolution as Allan Wright (†) called it, the ability to reproduce fine details in the presence high volume signals.

Instruments and voices come very natural and detailed and seemingly independent from the speakers. Presence and control of Bass is good. I do not own high efficiency speakers but run my amps with two Newtronics Temperances. Although the measured output power is little more than 20 W per channel I can hear music very loud. I just bought the 4 LP box from the 2013 crossroads guitar Festival.

Thus in conclusion do not regret one single Euro it put into this project, not counting the challenge and fun to develop and build it.

Regards

KlausB
 
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