DIY Audio Projects Forum

UPDATE: See my OddWatt Audio 5751 SRPP / KT88 Monoblock Tube Amp Kits review.

Hi guys, I got a pair of Odd Block KT88 Series 1 monoblock amplifier kits from OddWattAudio.com and this will be my build log. For those interested in the DIY version of this amplifier, see the Odd Blocks - KT88 Push-Pull Class-A DIY Tube Amp project page.

I have already built one of the monoblocks and finished photos have been posted in the Oddwatt Push Pull Tube Amplifier Projects thread.

Stock photo of the tube amplifier kit parts for one monoblock.

Before you start to mount the hardware, you need to scrape away some of the paint at the IEC socket and at the power ground. I started of with sandpaper, but the chassis is finished with thick powder coat so I quickly gave up and grabbed a Dremmel to scrape away some paint. A sharp knife works well at the IEC socket.

The instructions that come with the kit are very detailed. Before you start mounting the hardware, sort all the nuts and bolts - this makes it easy to identify as they are referenced in the instructions.

I made a slight deviation from the instructions. The 25-ohm pot was rotated 180 degrees - this way you can solder directly to the test points using the resistor leads so you don't have to use hook up wire. No big deal, but it is neater this way.

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

Boy, oh boy Gio! I want to get a pair of those kits so bad, If only I had the money and time to spend, summer being more than half over, I'm afraid I won't even get to the point of testing my Williamson amp before school goes back in.

But I will be watching your progress, and that is enjoyable enough for me, well.... that is if there are lots of pictures.

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My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700

• Project Page - Mini 12AU7 Tube Preamplifier
• Support/Questions - Mini 12AU7 Tube Preamp thread

Hi Alan, I will take a lot of photos. Sadly, finding time to work on the kit is the biggest problem.

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

"If I could save time in a bottle......."

Looks great Gio! I'll be following with much interest.

Cheers, Greg

The problem is I got the time but not the money.

Hi All, A sad but true thing. The kits (BTW) are not money makers. It is a good thing that I don't need the $$ to survive or I would starve. Now if I had the $$ a set of Martin Logans would be in my listening room. I have been informed that the combination of Odd Blocks and MLs is enough to bring tears to listeners.

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

Looks like a fairly complete kit they give you.

I look forward toyour results and reviw

Cheers!

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design

Next I deviate from the build order in the supplied instructions a little bit. I stuff the PCB mainly to get rid of all the loose parts so I don't loose any. Here are a couple photos of the PCB. Sorry about the fuzzy photos - it is a new camera and I guess I should take some time to read the instructions!
NOTE: The polarity of the diodes is incorrect in the above photo. Make sure you double check the polarity of all diodes and capacitors. The metal tab should line up with the thick white line on the PCB. Fortunately Rodney pointed this out to me prior to power up. Thanks Rodney.
I used a dab of silicone heat sink paste on the LM317HV regulator. Other than that, I followed the instructions.
Bare with me, but there will be more to follow in the next few of days.

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

Quick update - I got the second amp built on the weekend. I am very pleased with the mono-blocks. Dead quiet (zero hum with ear to Fostex FE206E drivers). The bottom end is solid and the response is smooth and detailed. Less than 20 hours on them so far, but I am happy right now. This is my first time hearing a 5751 and I like it. I'll roll it for some tubes I am more familiar with to check for sound differences.

I'll get more photos up in the next day or so. I also plan to get these on the scope too.

Cheers

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

Gio,

Congratulations on getting them finished. I am looking forward to pictures and scope results.

Alan

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Cheers, Alan
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