DIY Audio Projects Photo Gallery

KT88 SE UL tube power amp-finished

Sun, 01 Nov 2009 06:48:22 GMT

I had put the partially finished amp in the gallery some weeks back. Now finished not a lot of difference on the outside except for the many silver colored screws on the top plate and some feet. See the other image for the underside shot. After a number of hours of careful listening and listening to it though others CD players, pre-amps and speakers I can say that most liked the sound. SE tube amps produce absolute and exquisite mid-range and silky highs and deep sound stage but this amp has a slightly narrow sound stage presentation. Bass improved and hum vanished with additional PS filter caps. With a brushed Al top plate and Mirabue timber thick timber base, Edcor XSE OPTs and component-2-component wiring on all circuit boards (including rectifier broard) this amp represents a clean and easy build with in-expensive parts. Though low powered (6W+) for a few hundred dollars you can experience the benefits of a tube SE UL design. So easy, so nice!
34 views
Nov 01, 2009

KT88 SE UL tube power amp-underside

Sat, 31 Oct 2009 22:21:19 GMT

The underside of a KT88 SE UL power amp consists of, Edcor XSE series OPT, Hammond 10H choke, rectifier unit with SF diodes and 200uF of filtering. Turret boards were used for the KT88 sockets (ceramic), cathode resistors and bypass caps. All other components are wired, point-to-point, on a smaller circuit board X2 caps are used for the coupling caps. All component are inexpensive and readily available. The amp suffered from hum until the filter caps were increased. 100uF before and after the choke are required. The PS delivers a very quiet 410V. 30V is dropped across the cathode resistors which provide the biasing to the power tubes. At idle 63mA is drawn per tube. The sound is extended and detailed with a 6W delivery. Excellent sound stage depth. Frequency range is from 35Hz to 46kHz (-3dB points).
36 views
Oct 31, 2009

5751 SRPP / EL84 (6BQ5) Push-Pull Tube Amp (PoddWatt)

Mon, 19 Oct 2009 19:58:56 GMT

Another OddWatt tube amplifier. This one uses EL84 / 6BQ5 tubes in a self-inverting push-pull topology for the output stage driven by a 5751 SRPP. The gain is sufficient to allow direct connection to a portable mp3 player. As will all the OddWatt amplifiers, it measures very well and Bruce reports that it sounds very good. See the 5751 SRPP / EL84 (6BQ5) Push-Pull DIY Tube Amplifier project page for full details.
66 views
Oct 19, 2009

6V6 12AX7 Stereo Amp

Sat, 10 Oct 2009 13:14:33 GMT

Little stereo vacuum tube amplifier built for a friend who wanted a tube stereo at minimal cost. It used mainly parts on hand, including a vintage radio power transformer, vintage tube sockets, and NOS 5 watt Zenith audio output transformers made for 6V6 single-ended output stages. The driver tube is 12AX7 and the tube rectifier is 5Y3G. Output tubes are old Zenith 6V6G tubes, the tall ones that look prettier than the GT style. The tube amp delivers great sound with an MP3 player as the audio source.
136 views
Oct 10, 2009

Single End UL KT88 power amp MKII

Wed, 30 Sep 2009 12:09:37 GMT

This is the second of these amps I have built and this time for my son. He insisted he wanted a valve amp but with minimal on the top plate. All connection are to be hidden at the back and the volume control on its own plate on the front were further requests. In the past I have painted the top plate black but this time I was to leave the top silver. So it got my version of “brushed aluminum”. I think it looks better than black! The base is Asian Mirbeau.

The amp is not fully assembled yet with the internally wiring to go but all boards are populated inside. Once again I have used component2componet wiring on the boards. There is no printed cct. brds. Currently Sovtek KT88s are installed but this amp, like the first I built, will power: 5881s, 6V6s and EL34s. The preamp valve is a 6N1P which I think is a excellent little valve. And as stated the amp is SE UL configuration. Edcor XSE15 OPTs are used and a 10H choke with Hammond power tranni-374BX. Can’t wait to hear it !!!!

207 views
Sep 30, 2009

KT88 OddWatt Tube Amp and 5751 ForeWatt Tube Preamp

Tue, 29 Sep 2009 13:36:27 GMT

Wooden enclosures for a pair of Bruce's KT88 OddWatt Tube MonoBloc Amplifiers. Between the two mono amps is a new project - a 5751 (SRPP) ForeWatt tube preamplifier. The KT88 tubes are JJ / Tesla KT88 Blue Glass.
196 views
Sep 29, 2009

1930s style singled-ended pentode

Wed, 23 Sep 2009 19:58:50 GMT

This is a new amplifier I designed and built using mostly salvaged parts from British electronics of the 1930s and 40s. The valves are all British 4V types, AC/SP3 driver and N41 pentode output. The power supply uses an MU14 rectifier. The loudspeaker is a 1930s energized type - so it also acts as a smoothing filter.

See http://mike.wepoco.com/retro-geekery/wireless-world/1936-monodial-ac-super/monodial-psu for more information.
261 views
Sep 23, 2009

6C33C (6S33S) Single-Ended Valve Amplifier

Tue, 15 Sep 2009 00:23:10 GMT

6C33C (6S33S) Single-Ended Valve Amplifier with 6E5P preamp valves. The power supply is external to the amplifier. Additional details for this valve amplifier are available in the 6C33C Tube Amplifier thread.

258 views
Sep 14, 2009

6C33C (6S33S) Single-Ended Tube Amplifier

Tue, 15 Sep 2009 00:14:51 GMT

My new project, a 6C33C (6S33S) Single-Ended Tube Amplifier with 6E5P driver tubes. The power supply is contained in an external enclosure. Additional details are available in the 6C33C Tube Amplifier thread.

214 views
Sep 14, 2009

JAN6418 sub-mini tube preamp kit MKII

Mon, 14 Sep 2009 22:06:34 GMT

The MKII finished Oatley kit complete with 4oz brass knob. See other image for an internal photograph. The preamp has an excellent sound with good bass extension. This build was requested by an Australian women who saw the preamp article on the diyAudioProjects.com site. For more information about these little battery powered tube amplifier kits, see the JAN6418 tube preamp / headphone amp kit.
155 views
Sep 14, 2009

JAN6418 sub-mini valve preamp kit MKII

Mon, 14 Sep 2009 22:01:39 GMT

Yet another build of the Oatley JAN6418 valve preamplifier / headphone amplifier kit. This one was built to order. An Alps blue velvet pot and 4oz brass knob and pure silver hook-up wire add to the build quality.
186 views
Sep 14, 2009

MM Phono Preamp (battery powered)

Tue, 08 Sep 2009 23:31:42 GMT

My second build of the Jaycar MM phono preamp kit is house in a sleek enclosure and runs from Three 9V lithium batteries. An Alps Blue Velvet potentiometer is topped off with a solid brass black chrome knob. The preamp is very smooth sounding and better than my earlier version which uses an AC supply and regulators on board. See the MM Phono Preamp (battery powered) - inside image for an internal sview.
203 views
Sep 08, 2009

MM Phono Preamp (battery powered) - inside

Tue, 08 Sep 2009 23:26:40 GMT

This is my second build of the Jaycar MM phono preamp kit I have completed. This time I wanted it to run from batteries. Three 9V lithium batteries in series provide 27V. A resistive network produces a virtual +/- 13.5V supply for the OPA2134 opamp chips. The cct. brd.(PCB) can very easily be wired so diodes and regulators are not required. No track (trace) cutting is required and only a few simple straps and two resistors are required. An Alps Blue Velvet pot and pure silver wire, silver solder and gold RCAs make this a quality build. Bitumanised Aluminum foil lines the lid and bottom of a sleek compact ABS plastic enclosure to form a smart looking excellent sounding MM phono preamp. See the additional images.
264 views
Sep 08, 2009

NoyMark CS8412 + 8 x TDA1541A parallel battery powered nos dac project

Wed, 02 Sep 2009 18:16:07 GMT

I built a few big power set tube amps with big triodes such GM70, 833. I wanted to do something different and completed my first diy nos battery powered DAC project. It use CS8412 as digital receiver and 8 X PHILIPS TDA1541A parallel as dac circuit. As buffer, i used two mono opamps OPA627. It uses no digital or analog filter. Sounding incredible natural (even one of my friend describing it as organic), warm and also detailed. Very silent background. I am very happy to do this equipment, otherwise i had to pay very big money for same sound. After charging the batteries, it works more than 10hours continuously. When i turn off the dac, it charges the batteries automatically. You can see other photos below:
http://stereomecmuasi.com/forum/viewtopic.php?f=46&t=965
http://stereomecmuasi.com/cihazlar/muziksayi3/noymarkdac.htm
296 views
Sep 02, 2009

KT77 Push-Pull Tube Amp (OddWatt)

Tue, 01 Sep 2009 16:18:28 GMT

Even KT77s reach temps of around 225F Good bright heaters too. From rparsh.
Schematics are on the KT77 Push-Pull Tube Amplifier project page.
149 views
Sep 01, 2009

Bottom View - OddWatt KT77 Push-Pull Valve Amplifier

Tue, 01 Sep 2009 16:11:49 GMT

Bottom view of my build of the Oddblocks amps from rparsh. I decided to incorporate a switch on the CCS so I can also use this amp with my JJ KT88s too.
This build follows the OddWatt KT77 Push-Pull Tube Amplifier instructions by Bruce but I built mine as mono-blocks.
151 views
Sep 01, 2009

Massive Rectifier Vacuum Tube (Valve)

Tue, 01 Sep 2009 03:11:21 GMT

What a tube! This is a vacuum tube rectifier. 150 Amps with 6 channels.
172 views
Aug 31, 2009

KT77 OddBlock close-up

Tue, 01 Sep 2009 02:58:43 GMT

Oddblock KT77 close-up view. Instructions for this tube amp project can be found on Bruce's KT77 Push-Pull Tube Amp page.
135 views
Aug 31, 2009

KT77 Tube Amp with Guitar Speakers

Tue, 01 Sep 2009 02:56:51 GMT

Here the KT77 OddBlocks are powering guitar speakers. (by rparsh)
131 views
Aug 31, 2009

KT77 OddWatt (Push-Pull with CCS)

Tue, 01 Sep 2009 02:54:42 GMT

Finished KT77 OddBlocks by rparsh
This build follows the KT77 Push-Pull Tube Amp instructions by Bruce but as mono-blocks.
126 views
Aug 31, 2009

DIY Turntable

Tue, 25 Aug 2009 12:41:34 GMT

This is the Finished Turntable with Dynavector DV10X5 MC on one tonearm and a Shure M97XE on the other. Both tonearms were extended and DIY Headshells were used. The Sealed Lead Acid Battery does a great job powering the TT and with only an hour or two listening per day, lasts all week (Maybe longer??)
242 views
Aug 25, 2009

2SK1058 Single-Ended Class-A Amplifier. Retro style design.

Sat, 22 Aug 2009 23:09:14 GMT

Retro style design Class-A power amplifier with zero negative feedback. It was built based on the schematic of DIY Class-A 2SK1058 MOSFET Amplifier project by Mark Houston.
For more pictures and details, please visit http://alexkap.com.
286 views
Aug 22, 2009

Orion DIY speakers

Fri, 21 Aug 2009 23:50:15 GMT

These dipole speakers are available as a DIY project, a kit, or completed speakers. You can purchase the plans from Siegfried Linkwitz (www.linkwitzlab.com).
The speakers use two 10" Peerless subwoofers, an 8" SEAS midrange driver and two SEAS Excel tweeters per cabinet. The active crossover circuit board is also available from Linqwitz Lab. The documentation includes all that is needed to build these yourself. For those who want some of the assembly completed, the crossover is available fully assembled and tested. A kit, unique parts and brackets for completing the construction, and completed speakers are also available. The speakers are driven with 8 channels of amplification (60 watts per channel). One can parallel the woofers to get by on 6 channels. There is much information on the web about the quality of these speakers. Anyone seeking very high quality speakers at a DIY price for music reproduction or for home theater will not be disappointed.
370 views
Aug 21, 2009

JAN6418 portable Triode Headphone Amp MkII

Sun, 16 Aug 2009 14:46:53 GMT

The finished portable triode headphone amp/preamp on top of a pair of audio-technica “AIR” head phones and the Cowon S9 in front. This "out of the box" build of the Oatley electronics JAN6418 headphone amp / preamp has a delicious sound, is compact and quite unique. See other images. It may seem odd to be driving high-end headphones with a space age SS player (Cowon S9) with an amp which employs sub-mini valves developed for the military last century. But it sounds excellent. More information about this little tube kit is available on the JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit page.
173 views
Aug 16, 2009

JAN6418 portable Triode Headphone Amp MkII

Sun, 16 Aug 2009 14:31:25 GMT

The finished (second) headphone amp is assembled in a slim durable plastic enclosure lined top and bottom with bituminized heavy Al foil. You can see the lithium battery, printed cct. brd. and 6.5mm stereo phono sockets. In this build the stereo phono sockets have double pole double throw switches which are all employed, including the “real” switch. The switches make only when both devices are plugged into the amp. The idea is if you do not have devices plugged into both input and output and have the switch on then the unit is “off” with no battery drain. The battery is lithium so expensive bit I should get 80 to 100 hours of play out of this little portable triode headphone amp. See the JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit project page for full details.
182 views
Aug 16, 2009

JAN6418 portable Triode Headphone Amp MkII

Sun, 16 Aug 2009 14:18:55 GMT

This is a straight build of the oatley electronics sub-mini headphone driver and preamp. In other builds where the basic cct. brd. is used as a preamp the passive components are upgraded and the PT2308, headphone driver chip, though very good, has been upgraded. Not here. This build uses the stock components that came with the kit. See the JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit project page for more information and other build variations..
176 views
Aug 16, 2009

6T9 Hi-Fi Tube Amplifier Project

Sat, 15 Aug 2009 01:49:47 GMT

DIY build of a single-ended 6T9 Tube Amplifier using the PCBs from Spare Time Gizmo. The power and audio output transformers are from Edcor. Mark's 6T9 ultra-liner tube amp modifications were used.
179 views
Aug 14, 2009

6T9 Hi-Fi Vacuum Tube Amplifier

Sat, 15 Aug 2009 01:45:14 GMT

Rear view of the DIY 6T9 Tube Amplifier. The amplifier uses circuit boards purchased from Spare Time Gizmo. The power / filament transformer and audio output transformers are from Edcor. Mark's 6T9 ultra-liner tube amp modifications were also used.
171 views
Aug 14, 2009

Twinings Tea Box 12AX7 Tube Preamp with Remote PS

Wed, 12 Aug 2009 21:15:10 GMT

In this image you can see the RCA connections and power connections for the remote PS. An XLR plug and socket provide a solid connection for the power cord. Two sets of switchable inputs allows two devices to be selected. A three wire power cord provides 250VDC HT, 6VDC and common earth to the preamp.
183 views
Aug 12, 2009

Twinings Tea Box 12AX7 Tube Preamp with Remote 5Y3 PS

Tue, 11 Aug 2009 05:04:02 GMT

This is my second build of the Twinings Tea Box 12AX7 tube preamps with separate 5Y3 valve rectification. Others I have built used an internal or remote SMPS. This build used the massive and expensive Jensen copper, paper and oil caps. Silver wire, WBT silver solder, Solen Teflon caps (feedback) component-2-component wiring make this an exceptional build. There is no cct. brd. A remote PS with valve rec. (Ozzie 5Y3) and Hammond power transformer and 12H choke provide very clean robust power to the preamp Tea Box.

The sound is very 3D with sound stage deep and wide. The full passion of the music comes through with staggering detail making most instruments (acoustic anyway) sound very different. This build has been commissioned by a very astute audiophile in Denver, Colorado. I know he will be pleased. It goes with well used AWA (Amalgamated Wireless Australasia) 12AX7 valves, rare but sweet sounding.
164 views
Aug 11, 2009