I suggest that you build one but please post a specific schematic of direct us to a schematic. Pre amps are straight forward but I would have to see more.
sorry my english is very bad
i try to finde ,any good schematic with tone control to drive this speaker
i try to finde ,any good schematic with tone control to drive this speaker
The motional feedback speaker needs 1V on 100k to drive it.
What input sensitivity is needed for the guitar ? An what kind of tone-controls ?
But is this the right place for the question ? Transistor Amp and instrument input ,hardly a tube thing.
Mona
What input sensitivity is needed for the guitar ? An what kind of tone-controls ?
But is this the right place for the question ? Transistor Amp and instrument input ,hardly a tube thing.
Mona
i tought i had a simple question for that preamp
seems not
i want a ef86 as first tube and then a folower with tonestack as a fender
or perhaps just the ef86
and then in the mfb amp
seems not
i want a ef86 as first tube and then a folower with tonestack as a fender
or perhaps just the ef86
and then in the mfb amp
Guitar amp threads really belong in Instruments & Amps. I'll move it there which should also help your thread get the exposure it needs.
You'll do fine with Rod Elliott's guitar preamp.
Here's his entire project:
100W Guitar Amplifier (Mk II)
he sells the PCB by mail for a very reasonable price, I suggest you get one of them.
The preamp needs +/-15V at a few mA to power it.
Rod shows how to get them from the +/-35VDC he uses to power the 100W amplifier, but you can make a simple inexpensive independent supply.
He will very probably suggest one, but if not, ask here .
You'll need to house that preamp somewhere, from a thin rack type cabinet (very Pro !!!) to some general purpose electronics cabinet to a recycled VCR/DVD/computer supply/etc. chassis or even in pedal form.
In the latter case, you can make it so it's powered by a simple 12VAC wall wart supply so it's easier to integrate in a standardb pedalboard..
Here's his entire project:
100W Guitar Amplifier (Mk II)
he sells the PCB by mail for a very reasonable price, I suggest you get one of them.
The preamp needs +/-15V at a few mA to power it.
Rod shows how to get them from the +/-35VDC he uses to power the 100W amplifier, but you can make a simple inexpensive independent supply.
He will very probably suggest one, but if not, ask here .
You'll need to house that preamp somewhere, from a thin rack type cabinet (very Pro !!!) to some general purpose electronics cabinet to a recycled VCR/DVD/computer supply/etc. chassis or even in pedal form.
In the latter case, you can make it so it's powered by a simple 12VAC wall wart supply so it's easier to integrate in a standardb pedalboard..
Hi Civic,
The Philips 22AH587 is designed and marketed by Philips to be a studio monitor. If you have a working pair of them I would use them for this purpose and get a different speaker for your guitar because they are pretty good speakers. If you only have one unit then I guess why not use it for your guitar 🙂
The 22AH587 requires a line level signal at it's input. The units have three build-in power amplifiers, one for each speaker. The amplifier for the woofer contains a feedback loop which includes the woofer (there's a piezo element in the woofer, that is why it has 4 terminals instead of two), this feedback loop is active below 150Hz.
If you want to hook up your guitar you will need to have a simple pre amplifier that amplifies the signal from your guitar to line level. There are several transistor and vacuum tube (ecc83 based) circuits that can be found online that should be easy to implement.
I would suggest that you take a simple opamp or transistor based preamplifier with perhaps some tone controle and build it in the 22AH587. The 22AH587 has a dual power supply and provides +35 and -35 volt outputs. Voltage regulators like the 7815 and 7915 can be used to get the voltage down to suit the needs of the preamp.
The speaker is normally activated by an input signal. There is a small piece of circuitry that triggers a relais in the power supply. If you want to remove this simple bypass the connections for the power supply on the relais.
I notice that the service manual is written in Dutch, which is my native language. If you have any questions about the service manual please let me know. There is also a Dutch forum called mfbfreaks (mfbfreaks : Official Site) which is full of people who are passionate about Philips MFB speakers (even the original father of MFB is an active user 😉 )
I didn't read your post before posting this. Yes, that pre amplifier would be perfect for this speaker and can be build right into the speaker housing. All that has to be done is:
- Get the pre amplifier
- Build a simple power supply. 7815 (positive) and 7915 (negative) will get the voltage down from 35 volts to 15 volts, they only require small additional capacitance. If the pre amplifier only requires a few mA, then I don't think any heatsinking should be required (you can mount them on the metal casing of the internal amplifier just to be save).
- Drill a hole in the back panel for a 6,3mm jack
- Short the power supply relais (not the 12V for the coil, but the switching terminals)
- Connect the jack to the input of the preamp, connect the output of the preamp to the input of the 22AH587 (perhaps put a switch in there so you can also use the speaker in it's intended way) and connect it to a +15/-15 volts power supply.
The Philips 22AH587 is designed and marketed by Philips to be a studio monitor. If you have a working pair of them I would use them for this purpose and get a different speaker for your guitar because they are pretty good speakers. If you only have one unit then I guess why not use it for your guitar 🙂
The 22AH587 requires a line level signal at it's input. The units have three build-in power amplifiers, one for each speaker. The amplifier for the woofer contains a feedback loop which includes the woofer (there's a piezo element in the woofer, that is why it has 4 terminals instead of two), this feedback loop is active below 150Hz.
If you want to hook up your guitar you will need to have a simple pre amplifier that amplifies the signal from your guitar to line level. There are several transistor and vacuum tube (ecc83 based) circuits that can be found online that should be easy to implement.
I would suggest that you take a simple opamp or transistor based preamplifier with perhaps some tone controle and build it in the 22AH587. The 22AH587 has a dual power supply and provides +35 and -35 volt outputs. Voltage regulators like the 7815 and 7915 can be used to get the voltage down to suit the needs of the preamp.
The speaker is normally activated by an input signal. There is a small piece of circuitry that triggers a relais in the power supply. If you want to remove this simple bypass the connections for the power supply on the relais.
I notice that the service manual is written in Dutch, which is my native language. If you have any questions about the service manual please let me know. There is also a Dutch forum called mfbfreaks (mfbfreaks : Official Site) which is full of people who are passionate about Philips MFB speakers (even the original father of MFB is an active user 😉 )
I didn't read your post before posting this. Yes, that pre amplifier would be perfect for this speaker and can be build right into the speaker housing. All that has to be done is:
- Get the pre amplifier
- Build a simple power supply. 7815 (positive) and 7915 (negative) will get the voltage down from 35 volts to 15 volts, they only require small additional capacitance. If the pre amplifier only requires a few mA, then I don't think any heatsinking should be required (you can mount them on the metal casing of the internal amplifier just to be save).
- Drill a hole in the back panel for a 6,3mm jack
- Short the power supply relais (not the 12V for the coil, but the switching terminals)
- Connect the jack to the input of the preamp, connect the output of the preamp to the input of the 22AH587 (perhaps put a switch in there so you can also use the speaker in it's intended way) and connect it to a +15/-15 volts power supply.
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