Fjd Posted November 12, 2013 Share Posted November 12, 2013 My Nelson Pass ACA single-ended Class A mosfet mono amplifiers. Did you build these, I considered them at one point for the Class a single ended design. Which your input on the Nelson Pass designs. The ACA single ended amp is nice to build as it is now a complete kit and a person only needs to build the outputs (the power supply is actually two wall-warts that come with the kit). It distinctly has the Nelson Pass signature sound, but while a really nice sounding amp, I do think it is a step down from the F5, F3 or other full blown builds that I've heard. I've started a few Nelson Pass projects (including the F6) that are not kits, but it takes forever to source all of the parts, especially since a few parts for the Nelson Pass designs are now obsolete parts and more difficult to identify sellers with the genuine part. Quote Link to comment Share on other sites More sharing options...
Fjd Posted November 12, 2013 Share Posted November 12, 2013 (edited) I can't forget to show the inside of my Wright Sound Mono 10 amps. Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
Fjd Posted November 12, 2013 Share Posted November 12, 2013 (edited) Some believe they were fortunate to live through the golden age of audio. I believe I was fortunate to live through what may very well have been the 'golden age of cottage industry DHT amplifiers.' Here is one of my favorites, the Welborne Labs Terraplane 300b DRD amplifiers, complete with Western Electric 300b tubes (1999 vintage upon the remergence of Western Electric.....still amazed at what they sell for today). Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
seti Posted November 12, 2013 Share Posted November 12, 2013 I can't forget to show the inside of my Wright Sound Mono 10 amps. Thanks for posting. I am a big George Wright fan. I'm not as familiar with his mono 10 but they look interesting. Quote Link to comment Share on other sites More sharing options...
Fjd Posted November 12, 2013 Share Posted November 12, 2013 (edited) I can't forget to show the inside of my Wright Sound Mono 10 amps. Thanks for posting. I am a big George Wright fan. I'm not as familiar with his mono 10 but they look interesting. Here is what I had from George's website. Mono10 Power Amp The Mono 10 is our rated at 10 watts RMS, this push-pull, all triode amp has low distortion and high reliability like all Wright Sound products. The amp is based on our popular single-ended designs, with components being changed to optimize this type of operation. The amp runs Class A pp to about 6 watts, Class AB1 through 10 watts, and Class AB2 up to approximately 20 watts peak. The driver (6BL7) is operated as low impedance, high output to handle low mu output triodes (2A3), with a 6SL7 used as a voltage amp/phase inverter. There is no global damping/feedback used, so the sound is fast and accurate by design and with the use of the Magnaquest output transformer. When used with an unbalanced input, the phase inversion is done by percision resistors in a matrix sample and mix mode, meaning the phase is never more than 1% out of balance. In balanced input mode, it is truly balanced and does depend upon a balanced input source Priced per pair. Tube Compliment 6SL7 voltage amp and phase inverter 6BL7 low-impedance driver Pair Sovtek 2A3 (single-plate type) output tubes 5U4 rectifier Specifications Push-pull 2A3 power amplifier with low-impedance driver stage, Frequency response: 20 Hz to 20 kHz, +/- 1.0 dB @ rated output power 15 Hz to 35 kHz, +/- 1.5 dB @ one-watt output power Input configuration: Unbalanced RCA or balanced XLR (rear-panel selectable) Output impedance: 4, 8, 12, or 16 ohms Output power: 10 watts rms, 20 watts peak (nominal) Dimensions: 12 x 8 x 6.5 inches Mains voltage: 117 volts ac, 50/60 Hz Power dissipation: 110 watts (at idle) Features Zero feedback design Low hum Output tubes heated with ac current to ensure even cathode emission Easy operation with no adjustments of any kind required - ever Power supply uses filter choke to ensure superior filtering and long component life Point-to-point hand wired (always) Self-biased output tube stage requires no balance adjustment and maximizes tube life Removable IEC power cord Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
kaiser SET say Posted November 12, 2013 Share Posted November 12, 2013 My latest tube amp. Great bang for the buck. It isn't bad for $500 from agon but I still miss my Canary SET. The onix melody has 4 350Bs instead of 5881s. Tube porn I'd like to get some primo caps instead of the cheap chinese parts. Let me help you out with that beautiful Canary;-) Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 12, 2013 Share Posted November 12, 2013 (edited) dp Edited November 12, 2013 by Marvel Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 12, 2013 Share Posted November 12, 2013 OK, the Welborne Labs 2A3 Moondogs. I love these amps. I suppose some calamity would cause me to sell these, but I intend to keep these to pass on to one of my kids. Bruce Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 13, 2013 Share Posted November 13, 2013 The inside of my DIY single-ended KT88 tube amplifier that can run ultralinear or triode. Where did that iron come from? Quote Link to comment Share on other sites More sharing options...
Fjd Posted November 13, 2013 Share Posted November 13, 2013 The inside of my DIY single-ended KT88 tube amplifier that can run ultralinear or triode. Where did that iron come from? Heyboer did the transformer builds for the 25 kits that included the power transformer, filter choke and the two output transformers to the specifications below. Power Transformer 120/240V primary, 50/60Hz 750V, 200mA, center-tapped secondary 6.3V, 5A, center-tapped secondary 5V, 3.5A, center-tapped secondary Filter Choke 10 Henry, 200mA, rated at 500V Output Transformers 5,000 ohm primary with 6 ohm secondary load 20-20,000Hz flat frequency response across band 120mA, 500V rated primary, 25 watt output Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 15, 2013 Share Posted November 15, 2013 The inside of my DIY single-ended KT88 tube amplifier that can run ultralinear or triode. Where did that iron come from? Heyboer did the transformer builds for the 25 kits that included the power transformer, filter choke and the two output transformers to the specifications below. Power Transformer 120/240V primary, 50/60Hz 750V, 200mA, center-tapped secondary 6.3V, 5A, center-tapped secondary 5V, 3.5A, center-tapped secondary Filter Choke 10 Henry, 200mA, rated at 500V Output Transformers 5,000 ohm primary with 6 ohm secondary load 20-20,000Hz flat frequency response across band 120mA, 500V rated primary, 25 watt output Very nice....25 kits? Who built the other 24? Quote Link to comment Share on other sites More sharing options...
Taz Posted November 15, 2013 Share Posted November 15, 2013 Attached Thumbnails. Now that is down right NASTY Taz Quote Link to comment Share on other sites More sharing options...
Fjd Posted November 16, 2013 Share Posted November 16, 2013 The inside of my DIY single-ended KT88 tube amplifier that can run ultralinear or triode. Where did that iron come from? Heyboer did the transformer builds for the 25 kits that included the power transformer, filter choke and the two output transformers to the specifications below. Power Transformer 120/240V primary, 50/60Hz 750V, 200mA, center-tapped secondary 6.3V, 5A, center-tapped secondary 5V, 3.5A, center-tapped secondary Filter Choke 10 Henry, 200mA, rated at 500V Output Transformers 5,000 ohm primary with 6 ohm secondary load 20-20,000Hz flat frequency response across band 120mA, 500V rated primary, 25 watt output Very nice....25 kits? Who built the other 24? I think it is somewhat of an interesting story and probably a few lessons learned in relation to 'group-buys.' I first became interested in building something with KT88 tubes sometime in the fall of 2009, then while searching for information on the internet for a single-ended KT88 tube amplifier and ran across the following threads. http://diyaudioprojects.com/Tubes/KT88/ http://diyaudioprojects.com/Schematics/Mikael-Abdellah-SE-KT88-Amplifier.htm http://www.diyaudio.com/forums/tubes-valves/149614-stereo-se-kt88-build-abdellah-diyaudioprojects-design.html During 2009 and 2010 several people were building versions of this amplifier schematic from the diyaudioprojects site and were posting questions and results on the diyaudio thread above. I believe that Audiokarma also had a thread related to the Mikael Abdellah schematic about the same timeframe. I was looking at putting together a BOM myself and started pricing parts but it seems to take me a long time as my job (including the associated travel) prevents me from having large enough blocks of time to feel like I'm accomplishing much on what I want to build. However, I had a few parts set aside and already had a pair of electra-print output transformers that would have worked and was moving forward in building a version of this amp. About this time a guy named Scott, who had also shown an amp on this thread above, offered to organize a group buy and would engineer a complete kit if there was enough interest. He ordered parts to build 25 complete amplifiers, including the transformers from Heyboer, pre-punched chassis and made a very detailed assembly manual with clear pictures of each step and funded everything himself up front (I guess it must have probably cost close to $20,000 up front) and the kits priced out to about $850 each. Of course, several people complained that they could buy a Chinese made amp for $300 and the kit was too much cost for them, then people from the initial list of interested parties began to drop out and did not buy. I've actually built a couple of the kits and they are very straight-forward to build, included a lot of nice quality parts, and are very nice sounding amps (about 5 - 6 watts per channel in triode and about 10 - 12 watts per channel in ultralinear). Scott ended up with a thread in the DIY vendor forum and sold the remaining amplifier kits over the next two years and has been sold out for about a year now. I suspect that the lesson learned is that there will not be any more group-buys for this amp unless people pre-pay. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 16, 2013 Share Posted November 16, 2013 (edited) Attached Thumbnails . Now that is down right NASTY Taz Here, I'll let it all hang out sweetheart... Edited January 10, 2014 by mike stehr Quote Link to comment Share on other sites More sharing options...
Fjd Posted January 9, 2014 Share Posted January 9, 2014 (edited) It seems like the right time to bump the Amp porn thread with my stereo VRD amplifer including the famous Mojo Dijon capacitors. Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
kaiser SET say Posted January 9, 2014 Share Posted January 9, 2014 Now I don't want to say I'm a Fanboy, OK, I'm a Fanboy http://balanced.com/products I just love Viktor's work, pick one, any of them and they are as beautiful on the inside as they are on the outside. Man they sound terrible too Quote Link to comment Share on other sites More sharing options...
Fjd Posted January 26, 2014 Share Posted January 26, 2014 Listening to DIY clones today. Here is a quick look at an Aleph J clone. Quote Link to comment Share on other sites More sharing options...
Fjd Posted January 26, 2014 Share Posted January 26, 2014 (edited) Next on the DIY schedule was a Gainclone chip amp using the LM3886 amp. The 150 watt per channel Rawson BPA300. Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
Fjd Posted January 26, 2014 Share Posted January 26, 2014 (edited) What does a person do with a roached McIntosh MC250 when a couple of LM3886 modules are left? Why he makes a McGainclone.....I actually bought this from a retired technician that was interested with experimenting with the gainclone chips and I was intrigued with what he came up with here. By the way it has a pleasing sound to it (similar enough to be a cousin to the Mc250). Edited November 9, 2014 by Fjd Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 26, 2014 Share Posted January 26, 2014 Listening to DIY clones today. Here is a quick look at an Aleph J clone. I have always wanted to listen to the First Watt stuff. I have this on my to build list. Dave Quote Link to comment Share on other sites More sharing options...
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