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Good day,
I have been thinking about building a low power but good sounding amplifier, I’m either class-A or class-A/B.
I came up with the above schematic from studying a few Germanium Transistor based schematics. The amplifier makes use of a class A preamp and class a/b power amp, which both work on 9vdc.
The goal is to build a nice sounding tabletop music player. Not building the next pass zen, but I want a better sound than what is found on the market from something using low voltage.
I threw the schematic together while at work, so it probably has errors. I will run it in spice later as well.
My limited audio knowledge rests with vacuum tubes, so I would like some assistance, please.
Any advise is welcomed, but please don’t mention how bad Germanium Transistors measure. I know, but I like their sound.
Thank you all in advance.
Good day,
I have been thinking about building a low power but good sounding amplifier, I’m either class-A or class-A/B.
I came up with the above schematic from studying a few Germanium Transistor based schematics. The amplifier makes use of a class A preamp and class a/b power amp, which both work on 9vdc.
The goal is to build a nice sounding tabletop music player. Not building the next pass zen, but I want a better sound than what is found on the market from something using low voltage.
I threw the schematic together while at work, so it probably has errors. I will run it in spice later as well.
My limited audio knowledge rests with vacuum tubes, so I would like some assistance, please.
Any advise is welcomed, but please don’t mention how bad Germanium Transistors measure. I know, but I like their sound.
Thank you all in advance.
How are you biasing the power transistor? I do not see any provision for bias setting or stabilization.
Flowing DC through the speaker is generally considered rude. It pushes the coil off the center of the gap, and causes useless heat.
I'm surprised at the BC108. There are Ge NPNs. Small Bear Electronics in NYC has buckets.
Flowing DC through the speaker is generally considered rude. It pushes the coil off the center of the gap, and causes useless heat.
I'm surprised at the BC108. There are Ge NPNs. Small Bear Electronics in NYC has buckets.
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Thank you for your reply, I was hoping you would.
I thought that connecting straight to the speaker was odd, but I’ve never worked with SS outside some JFET kits. I’m assuming an output cap is in order, I’ll get it in spice and play around with it as soon as I get some time.
The BC108C was a typo on my part, should be BC109. I will fix that.
I used a couple old Schems, one being Russian.
Thank you for suggesting Little Bear, it happens to be nearby
I thought that connecting straight to the speaker was odd, but I’ve never worked with SS outside some JFET kits. I’m assuming an output cap is in order, I’ll get it in spice and play around with it as soon as I get some time.
The BC108C was a typo on my part, should be BC109. I will fix that.
I used a couple old Schems, one being Russian.
Thank you for suggesting Little Bear, it happens to be nearby
MP-40 low-power (150 mW) for current up to 30 (100) ma. In the output stage, it is better to use a medium power transistor P605 with a heatsink.
In a single end, you will not get more than 20 mW of power.
This may be sufficient for sensitive headphones.
In a transformerless push-pull, you could get up to 300-400mw / 8 ohm at 9v.
In a single end, you will not get more than 20 mW of power.
This may be sufficient for sensitive headphones.
In a transformerless push-pull, you could get up to 300-400mw / 8 ohm at 9v.
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Thank you all very much for your comments and information.
I ended up puchasing a good working chassis from a Zenith Z419L. It's single-ended, but uses Si transistors .. Oh well, it sounds good.
Preamp uses a 121-430 and output is a 121-436. I have no Schematic, but I will draw one up.
This chassis will be used in a Crosley 52TF shell; I'll be posting a new build thread shortly.
I ended up puchasing a good working chassis from a Zenith Z419L. It's single-ended, but uses Si transistors .. Oh well, it sounds good.
Preamp uses a 121-430 and output is a 121-436. I have no Schematic, but I will draw one up.
This chassis will be used in a Crosley 52TF shell; I'll be posting a new build thread shortly.