There was an upgrade version of line level amp some years later. I will try to find it. I gave away the circuit and one DIYer built it and published... also in TAA.
THx-RNMarsh
Hi Mark,
diyAudio member jackinnj, is providing PCBs, at cost, as well as critically matched active devices and, I believe, at kit for Mr. Marsh's headphone amp.
Cheers!
Rob
diyAudio member jackinnj, is providing PCBs, at cost, as well as critically matched active devices and, I believe, at kit for Mr. Marsh's headphone amp.
Cheers!
Rob
The updated version was in your Pooge 3 article in the 4/85 issue and then the DIYer (Thomas Howe) described it again in an article in the 1/89 issue.
---Gary
Thanks but I've already built the jackinnj boarded RM HPA, with commentary and measurements earlier in this thread a few weeks ago.
I am in Mexico now and some where a few hours flight south of Mexico city in old town. Hot and humid. Big deal here as it was the country independance day from spain. Be back in a week or so.
Any new listening results?
A business in Thailand wants to build it commerciallly and sell it world wide in a few months. Dont know what cost will be but more than DIY is certain.
-Richard
Any new listening results?
A business in Thailand wants to build it commerciallly and sell it world wide in a few months. Dont know what cost will be but more than DIY is certain.
-Richard
I have multiple thousands of output transistors if they need 'em. You can have them contact me.
Multiple thousands !! wow.
Have they all been gone thru for matched pairs?
-RM
BTW -- I will still support the DIY'er in making the HPA.
Have they all been gone thru for matched pairs?
-RM
BTW -- I will still support the DIY'er in making the HPA.
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I use 669/649 instead of the On-Semi 300/310. They are discontinued TO-126 parts so were very inexpensive.
I found that the THD% is a bit lower than the On-Semi parts.
There are many good power supplies now. But few say why they are good... just do a version of someone's ideas.
I attempted by the mid 1980's to explain the why as well as introduce a better topology for audio apps. First published in 1983 in TAA called Power Up. An overview of power supply considerations. Then followed by specific topology for best performance regulator topology in 1988 titled Push-Pull Shunt Reg from work during 1986.
One of the better recent versions was also by Borbely in Feb 2008 AudioExpress.
Push-Pull Shunt regulators are my preferred for the HPA.
THx-RNMarsh
I attempted by the mid 1980's to explain the why as well as introduce a better topology for audio apps. First published in 1983 in TAA called Power Up. An overview of power supply considerations. Then followed by specific topology for best performance regulator topology in 1988 titled Push-Pull Shunt Reg from work during 1986.
One of the better recent versions was also by Borbely in Feb 2008 AudioExpress.
Push-Pull Shunt regulators are my preferred for the HPA.
THx-RNMarsh
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Actually I stopped using Johannes when a course instructor in LA asked me whether I was a prince.
"Huh? No I am not".
"Then why do you call yourself yourhighness"?
True story!
Jan
"Huh? No I am not".
"Then why do you call yourself yourhighness"?
True story!
Jan
I have your address somewhere, and my wife is anxious for me to downsize.
For the record, about 300 folks have purchased PCB's (at cost) and kits of matched semi's.
When I am done with the JFETs, I am done...