DIY Audio Projects Forum

Never sip wine and troll eBay. I purchased this kit while checking out other components on eBay. As you can see the brd. is about the same length as my pliers. The kit is all you get for your $48 and you need to add, power tranni, heat sink, case etc. The 6N3 works in differential mode with the +\- 45V from the PS. All PS parts are on the cct. brd. and speaker protection is included.

Not a kit for the beginner with the BOP and the sketchy schematic not always agreeing. Very small solder pads and lots of parts make the assembly of the brd. taxing. The amp should produce better than 80W pc and I will be using two power trannies in parallel to supply enough current at the required voltage. Why two I hear you ask and not one? Because I could purchase these trannies from work at staff prices but they were not up to the current required so two will give me a 320W tranni supply. More than enough capacity at a fraction the price of a single tranni if I had to source it else where.

The enclosure is a 2U 19" rack mount. The HS I also got from work just fits in. I will use a small mains filter and have three selectable RCA inputs.

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

Completed the amp after suffering a few bouts of builders constipation. Sounds fine so far but I have just realized I can't use my stereo sub-woofers which were usually split off from the preamp. This being an integrated amp with no preamp split off. I may look to run the subbies from the speaker terminals. I am expecting a little more base here and my 2-awys go easily to 50hz so I may miss nothing.

Very pleased with the build both inside and out. Im getting neater in my very old age. Three switchable inputs on the back and 80 RMS pc makes this an easy to live with integrated.

Name of the amp you ask: "Number 9". You have to think Woodstock double LP to work this one out. Any clues?

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

if you are looking to purchase the brd. it is from findhifi : http://www.ebay.com.au/itm/Tube-6N3-Preamp-TDA7294-Power-Amplifier-Kit-DIY-80W-x2-/121063467216?pt=AU_Electronics_Audio_Amplifiers&hash=item1c2ff1e8d0

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

As always the first few hours on any amp never reveals the true character of the sound. After about two hours the amp started to perform. Initially it was very grainy and a little harsh sounding but a few hours in the music started to flow better. Where my tubes amps reveal triangles, tambourines, bells and chimes beautifully these were a little more hidden and not as well defined. Violins sounded good, raw and earthy but just some of the more delicate sounds, which my tube amps reproduce with easy, appear a hidden. It's early days so things may well change over the next 50 hours or so.

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

Hi Mark, Nice build. With more wine the sound will improve without having to wait 50 hours. On the eBay bit... been there and done that. Sometimes it works out well, and then.....


Good listening
Bruce

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Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Very nice build Mark. It's easy to get tempted with e-bay...

May I ask you where you get these beautiful engraved nameplate, these really add to the look of all your build. Do you engrave the text yourself. Great job as always.

I heard that the 7293 sound quite nice, I didn't know about the 7294.

Rgds,
Iso

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DIY SS Amp : LM3875 GC | TA2024 | TA2020 (AMP-6) | TA2022 | Amp Camp Amp | JLH
DIY Tube Amp : RH84 SE | 6V6 SET | 13FD7 SET (Chinook) | 807 UL SE | 6BQ5 Class A PP UL | 6LR8 SE
DIY Spkrs : Cyburgs Needle | MLTL (FE206E) | CSS EL70 BR | Open Baffle (Alpha 15A + FE206En) (in process...)
DIY Pre-Amp : MooseFET.
To come : MLTL (CSS enabled EL70) + more tube amp...

I got friendly with the local engraver Geoff. I had trained his predecessor to produce exactly what I wanted in a name plate then he left the business. It took sometime before Geoff really got up to speed but now he likes doing my plates and does a fantastic job. We have become good friends. He only charges me $20 a plate regardless of what I want on it. But I buy about one or more a month from him. I print on paper what I want and take a photo with my phone camera. I SMS this to him and he tells me when I can pick it up. Usually only takes a day. He does them all by hand and a lot are quite stylish. The plates are solid brass with a sticky back.

Bruce: Most of the time the eBay purchases work out well. If I had of thought about the amp kit I may not have bought it. It was an impulse purchase but the amp sound very good so I'm happy. The amp has plenty of power and plays very loud with no stain. I get more congestion from the speakers but only when playing real loud. I have two friends with Quad speakers. It should drive them easy.

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

Neat project Mark.

Do you get those enclosures cheap at work? They are a pretty neat way to get something less bespoke/ more incognito looking. I like it.

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Thanks,
Ross in Wisconsin

Retail they are $AU109 but with staff discount they are a lot cheaper. These days they are really nice looking. Stippled charcoal though they are labeled black.

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |

It's nice to be able to lift an amp which doesn't try to rip your arms out of their sockets. I took Number 9 to Dave's place to drive his 400lb 6 foot dual 12" woofer Osborn's. They are really quiet efficient, up around the 92db mark. Dave's CD player\preamp is a La Fontaine, shockingly expensive, with a tube driver stage.

Number 9 drove the speakers with extreme ease and very deep and full bodied bass. Strangely the amp appeared to take an hour to warm up before both of us were really digging it!

Dave started the afternoon with his new 250W RMS pc bipolar SS amp. Number 9 couldn't match it in all-out bass aggression but if you had only heard Number 9 first you wouldn't know it. But when it came to mids and highs Number 9 was (to me) a clear winner. Dave's 250W monoblocks just didn't seam to have any finesse. A great Rock amp but when it came to Classical or vocals it was far too grainy, too course and (to me) unbearable.

10 out of 10 Number 9.

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Projects: "Precision" - 300W Class AB Holton power amp | "retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp |