yeah ,even harmonics are important in a motor.
the triumph tiger is an excellent motorcycle, and on the first models there is still a hatch to change the starter freewheel easily 😉
one of my favorite engines is the triumph three cylinder.
I have been working on building a replica of this one for almost 10 years.
but there is little technical documentation so I do everything with photos for the cycle part and for the engine, I will do with my knowledge.
I had a friend who had a power bench, a flow bench and a magnetoscopic lathe for dynamic balancing of crankshafts but he died last year.
maybe that will tell you something
the triumph tiger is an excellent motorcycle, and on the first models there is still a hatch to change the starter freewheel easily 😉
one of my favorite engines is the triumph three cylinder.
I have been working on building a replica of this one for almost 10 years.
but there is little technical documentation so I do everything with photos for the cycle part and for the engine, I will do with my knowledge.
I had a friend who had a power bench, a flow bench and a magnetoscopic lathe for dynamic balancing of crankshafts but he died last year.
maybe that will tell you something
That is beautiful. Sorry to JLH builders. I love the frame triangulation. The wheels also. If was to do one thing it might be modern forks like on the Guzzi.
The Ducati is a sine cosine wave set up that has near perfect primary balance. There are combustion harmonics. The BMW at 180 degrees also has good balance. Mike Hailwood proved the value of the Ducati at the TT when quite old. My girlfriend Kim's dad was Mike's mechanic. Ducati has a very low wind resistance and near perfect torque curve. Mike's Ducati only had 72 horse power at the rear wheel. It beat everything. A Ducati was more advanced than the Cosworth in many ways.
The Hitachi MOSFET amplifier worked much like BMW. Many opamps also. BMW if I remember won the 1939 TT. That was a little bit unusual.
My uncles friend Harry Weslake invented gas flowing. He was a gas engineer. He used his gas meters.He converted his engines to compressors and measured the flow. They lived in Rye Sussex.
The Ducati is a sine cosine wave set up that has near perfect primary balance. There are combustion harmonics. The BMW at 180 degrees also has good balance. Mike Hailwood proved the value of the Ducati at the TT when quite old. My girlfriend Kim's dad was Mike's mechanic. Ducati has a very low wind resistance and near perfect torque curve. Mike's Ducati only had 72 horse power at the rear wheel. It beat everything. A Ducati was more advanced than the Cosworth in many ways.
The Hitachi MOSFET amplifier worked much like BMW. Many opamps also. BMW if I remember won the 1939 TT. That was a little bit unusual.
My uncles friend Harry Weslake invented gas flowing. He was a gas engineer. He used his gas meters.He converted his engines to compressors and measured the flow. They lived in Rye Sussex.
It's a great time for experimenting. Am I alone in finding it difficult to focus? I have enough parts if not too picky to build most things. How about other people?
It is a good time to be taking precautions against being infected by Covid-19. That will be most peoples primary focus especially if they have families.
Exactly. I have been maximising efforts. Unfortunately shopping is unavoidable. It is a great time to do things. My ex wife became trapped here. I have to tell her to do the right things.
OMG !!!
again, this is where forums admit their limits.
In real life, I will have already jumped in my car or on one of my motorcycles and I will have come to see you with a bottle of wine to talk about it in real life !!
I still have several amps on the go for the next few days, BUT, it might be a good idea to open a new thread on the GEM, right?
I did not understand a quarter of half of the modifications made by Graham on the jlh but I know it by reputation, and as I also know the JLH, the idea made is way in my head.
even if it means being blocked (and for a while longer) take the time to do things. 🙂
I had no Idea Bruce Crozier was his mechanic. My uncle made a few tractors called Westfield with Harry. Unlike David Brown nothing came of it. Weslake twin engine much like a Triumph. My Great Uncle Frank Saunders built the harbour wall at Dover. Officially a farmer. He had the concession to extract sand. Tram Road Rye was Weslake. The tram was for the materials. Frank was exceptionally like French people. Food was the only sign he was rather rich. He lived in an identical house as his workers. He sold the land for Pontins holiday camp. That's a terrible thing he did.
perhaps there are things to do better than taking up the history of the GEM which must be a little old for him.
but it's worth asking him the question
but it's worth asking him the question
I will get the laptop out to read the small print. A+AB is so logical. Dynamically AB can be less coloured and cheaper. There will be a small compromise in the transition area. Douglas Self has a patent for asymetrical bias offset. I would set current to 250 mA.
You are right! I Just finished the JLH 2005 Geoff Moss ESL amp with PCB posted in this thread. I'll listen and measure the next days. I need a lot of current to drive a magnetostat, so i decided to build this well proven design.
Of all the threads about Amps now I ve read through for me the most appealing is the DLH Amp discussed in this forum since a very recent developement with an very simplistic approach and it also measures very well.
If it werent for my special project, I would have tried the dlh
at the risk of repeating myself.
I assembled them all and I always came back to the simplest original diagram.
I tried several signal transistor combinations but not the last work of a member from here who worked a lot on it.
on the other hand, I know the work of DR Maynard, and I only heard good things about it, that's what piques my curiosity
I assembled them all and I always came back to the simplest original diagram.
I tried several signal transistor combinations but not the last work of a member from here who worked a lot on it.
on the other hand, I know the work of DR Maynard, and I only heard good things about it, that's what piques my curiosity
midpoint voltage problem
Hallo,
as My first project I just build chinese JLH clone based on original.
I have a problem adjusting midpoint voltage.
I use 27v and midpoint can only be adjusted between 1-3v.
Any input is highly apreciated.
Kind Regards,
Jolbe
Hallo,
as My first project I just build chinese JLH clone based on original.
I have a problem adjusting midpoint voltage.
I use 27v and midpoint can only be adjusted between 1-3v.
Any input is highly apreciated.
Kind Regards,
Jolbe
Check for shorts between the power transistors and the heatsink. Check for a short from Emitter to Collector on the lower power transistor (the one that connects to ground (1969) or the minus rail (2005)).
Starting to read some data by the son of the GEM amplifier designer. The conclusions are interesting and thought provoking. I think the GEM amplifier is unnecessary complex for the stated reasons it was designed.
What I quickly understood is the JLH design can not be universal and sensible speakers must be used. I could imagine Spendor Prelude would be a good type. It used a BC3 bass unit at 90dB / watt.
He says a KT88 design to be better than a 100 watt JLH . I find that an unusual concept.
A power boosted op amp with primitive bias should do something interesting. How negative feedback applied might be critical. I built a complimentary feedback pair type without loop feedback. Very low distortion. Damping factor wouldn't be very high.
What I quickly understood is the JLH design can not be universal and sensible speakers must be used. I could imagine Spendor Prelude would be a good type. It used a BC3 bass unit at 90dB / watt.
He says a KT88 design to be better than a 100 watt JLH . I find that an unusual concept.
A power boosted op amp with primitive bias should do something interesting. How negative feedback applied might be critical. I built a complimentary feedback pair type without loop feedback. Very low distortion. Damping factor wouldn't be very high.
Sadly, Graham passed away in November 2014. RIP Graham Maynard Thankfully, his legacy of contributions and helpful comments remains here with DIYaudio, for as long as it's online.
I'd agree that whilst very interesting, Graham's work and articles are really another topic that deserves its own discussion thread if someone wants to revisit them and rekindle interest. Otherwise, this thread will once again lose its way in off-topic chat and so lose its following.
Also The GEM is far from simple unlike the JLH. As said the GEM is an answer to a problem that shouldn't exist. It's impossible to make the JLH into a universal amplifier. That's more a critism of loudspeaker design.My speakers from my previous larger house were giving 115 dB measured at about 20 watts at the listening position. The JLH would have brought that down to a sane level The problem was it was beautiful to listen to. The old Mission 760i I use for now sound nice enough. I never listen above 96 dB and usually that needs impeccable recordings. Celestion SL6 would probably better them. At 82 dB per watt the GEM idea is interesting with the Celestion SL6. I dislike metal tweeters, the exception are these.