Anyone build their own amp here?
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BinaryMike
Pelagic EE
I design and build tube amps, but I tend to mix in a few transistors here and there.
I am planning to design a tube hifi amp in the future, I designed two tube guitar amps with power scaling and channel switching. This is a change to design a SS power amp.
What kind of tube amp you designed? SE or PP? I like to hear more.
I hope more people design and build amp join this forum. It's too boring to just fix or restore amps, it's a lot more fun and challenge to go from ground scratch.
petehall347
the brandy coffee man
i used to when i was around 11 years old but not bothered since .. have always wanted to build some nice valve amps to sell on but realised its just a dream unless i suddenly get super rich money wise .
it may still happen i am only 55 ...
p.s the ones at 11 years old were so i could use a speaker instead of headphones with my crystal radios i built from scratch .
it may still happen i am only 55 ...
p.s the ones at 11 years old were so i could use a speaker instead of headphones with my crystal radios i built from scratch .
Forget about making money, I question whether most of the successful designer like Nelson Pass making a lot of money. Let's face it, market is dominated by companies like Pioneer, Kenwood, Adcom, Marantz etal. They build their brand name throughout the years.....and most people don't even know or care enough about sound. The market of high end stuffs is very limited.
This is like guitar amps or other music electronics, there are so many small boutique amp companies out there that barely survive or not even surviving. Everyone has a great idea and design they think they can make it. But there are just so many out there fighting for a very small piece of pie. I actually designed and build two guitar amps that are very good. I even own a patent in noise cancelling for guitar with single coil pickup that retain 100% of the original sound of the pickup. I never really try to market it. I finally move to audiophile amp and I design just for myself to enjoy. I have been an EE designing all sort of electronics for 30 years.
Electronics has always been my hobby. I retired and I am doing it as a hobby now. I have only myself to please, BUT I am taking it very serious. This is my first audiophile amp, I yet to run it through speakers. But I did FFT test and I got 0.0015% THD at 1KHz with 26V peak to peak into 4ohm load. Less than 0.005% at 10KHz. This is very good by any standard. I am doing a second run of pcb with improvement. I am using 9 pairs of output transistors instead of only 5 pairs in my first run pcb. This is a high bias class AB amp with the first 5 or 6W in class A.
This is like guitar amps or other music electronics, there are so many small boutique amp companies out there that barely survive or not even surviving. Everyone has a great idea and design they think they can make it. But there are just so many out there fighting for a very small piece of pie. I actually designed and build two guitar amps that are very good. I even own a patent in noise cancelling for guitar with single coil pickup that retain 100% of the original sound of the pickup. I never really try to market it. I finally move to audiophile amp and I design just for myself to enjoy. I have been an EE designing all sort of electronics for 30 years.
Electronics has always been my hobby. I retired and I am doing it as a hobby now. I have only myself to please, BUT I am taking it very serious. This is my first audiophile amp, I yet to run it through speakers. But I did FFT test and I got 0.0015% THD at 1KHz with 26V peak to peak into 4ohm load. Less than 0.005% at 10KHz. This is very good by any standard. I am doing a second run of pcb with improvement. I am using 9 pairs of output transistors instead of only 5 pairs in my first run pcb. This is a high bias class AB amp with the first 5 or 6W in class A.
Hey. that's very good, a lot better than just fixing and restoring. Most designs are quite standard. Even I design without referencing to any particular schematic, but basically it's a complementary IPS with current mirror load, EF VAS to increase the gain of the IPS stage. 3EF OPS stage to increase the gain of the VAS stage. It's the small little thing that improve from the basic design of the original schematic.
eg. I use folded 3EF to increase the voltage swing and better temperature tracking. What I meant folded is PNP driving NPN driving NPN output stage instead of the standard NPN driving NPN driving NPN. You can see I gain 1.4V of voltage swing per rail or 2.8V total swing of the output because the PNP and NPN cancel out. Also, I bolt the PNP predriver and the NPN driver together so their Vbe temperature drift cancel each other out. It work out really well. I got less than 10% bias current drift from stone cold to really hot( driving with large signal).
BinaryMike
Pelagic EE
Here are a couple of my designs with good published descriptions here on AK:
http://audiokarma.org/forums/index....-pentode-power-amp.464003/page-2#post-9046145
http://audiokarma.org/forums/index.php?threads/bonseki-20-20.707123/
Both of those designs are focused on squeezing a lot of performance out of very low cost components. I have a third concept of this type in the works, but I'm also building a single-ended triode amp with OPT secondary flux cancellation. There's an oddball 50 watt per channel autoformer-coupled SEPP tube power amp in the pipeline too.
BinaryMike
Pelagic EE
My situation is similar, except that I had a career as an analog video circuit designer. I recently spent a chunk of my children's inheritance on test gear, including a new Tek 350MHz scope and a Stanford Research distortion analyzer, to gain maximum visibility into circuit behavior. I hope to gain a bit of notoriety as an unconventional tube amp designer before they carry my butt away!
I looked through your other thread, very nice. Did you get permission from your big boss before you use the cookie pan?!!!
You have the 2465A scope? That's what I have. I am using the QuantAsylum QA400 for FFT test. I am looking for a better Spectrum analyzer or distortion analyzer. I prefer to stay with spectrum analyzer as I want to see the peaks of all the harmonics rather than just look at the numbers.
BinaryMike
Pelagic EE
The new scope is an MDO4034B-3. I bought it when Tek was closing out the older models and got a huge bundle of apps in the deal.
Electronics is my passion all these years, I worked in jobs of totally different fields just to learn more. In the late 70s and 80s, I change jobs quite often, I even worked for LeCroy for 3 years designing front end of the digital scope, but those were really slow back in the days. Then I went to Exar to design analog ICs for a while, then to Seimens to design the front end of the Ultrasound medical image scanner. Then I settled down and worked in designing various mass spectrometers for over 10 years. Then I ventured out into optical communication and military Land Warrior project. I retired for close to 10 years until the old company called me up for a contracting work that lasted for a year and half. Just finished the contract last Oct. so I am back to my power amp again.
I want to try a SE tube amp in the future, but I would like to finish this one and maybe one more closer to Aleph type design before moving to the tubes.
JRhoBurton
All roads lead to music
I like to repurpose stuff and sometimes an amp results. In my case, it would be based on available modules.
http://audiokarma.org/forums/index.php?threads/sony-str-v5-parts-to-live-again.649367/
This is now working, been my main amp for a few weeks. Still need to do some tweaks, but it sounds fine.
http://audiokarma.org/forums/index.php?threads/sony-str-v5-parts-to-live-again.649367/
This is now working, been my main amp for a few weeks. Still need to do some tweaks, but it sounds fine.
Isn't the two big round disc too heavy at 22lbs each?
I notice you have transistors on the power supply filter board, is that for voltage regulation to get rid of the ripple? I am doing that using a simple MOSFET circuit. I just use the Vgs to create like 4V drop to give room for the ripple from the transformer.
You buy the amplifier pcb on ebay? What kind? I was looking at the Hiraga pcb kit on ebay, thinking about doing one quick and easy.
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JRhoBurton
All roads lead to music
I ended up using a thinner disc for the top. I might build a second amp with the other thick one, since I have a transformer from a V6 and another pair of big heat sinks. I used a rectifier board module from the Bay, and a couple of LJM mosfet boards. I think they are called L150. LJM is a Chinese designer who has a pretty good reputation, although it's not real clear which supplier has the best implementation. I still need to test power output but the amp sounds good and is very quiet.
slimecity
Super Member
This guy is my new hero. Especially after issuing his VFET amp design kit over on diyaudio - buying the kit gets you genuine matched VFETs and tons of support, I doubt he's making much money by doing this, but a lot of kudos and respect. Plus its pretty great that he personally contributes regularly to the forums.
Yes, I like him a lot. He design good amplifiers. I bought and restored a Nakamichi PA-7 he designed that is very much the Threshold S300 with 7 pairs of output transistors instead of 8 in the S300. His old amps still fetch good price on ebay. Can you give me a link to which VFET amp you referred to? You build any of his amps?
Do you have the schematic that you can post of the L150? I like to take a look. One thing, from the picture, it only has 2 pairs of output transistors. It would be nice to have like 4 or more pairs to lower the crossover distortion further.
slimecity
Super Member
This is the one - I built this using Hammond chokes (not a Pass design but really a Rothacher/diyaudio design): http://www.diyaudio.com/forums/pass-labs/201655-lamp-simple-sit-amp.html
And this one discusses the build of the VFET kit issued by Nelson - enquire there on how to get put on the wait list to buy one.
http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a.html
The problem with the top one is your sourcing a good matched pair of genuine VFET that are working properly - very hard to do - I could help out however if you decide to follow this path and ilimzn (member here) is a great source of VFET info too).
JRhoBurton
All roads lead to music
I have no schematic, but the boards look like this.
They use IRFP240s, 6 per channel.