Whats on your amp workbench?

[Bg]

He really did do nice work that bloke. I wonder if the driver is a 6n2p; like a 12ax7 but with a grounded shield between the two sides.

I need to have a closer look at the valve - markings were a bit obscure, I scoped the output from the preamp and knew that was ok.

The 1 watt I owned and regret selling was massive through a big cab

and the ones I've seen, always have big iron!

[Slowy]

Here's a question grounded in profound ignorance. Please not to laugh, I seek enlightenment. For the sake of brevity I will phrase it this way:

If you have a single impedance amp ( say 8ohm) and a 16 ohm speaker, could you not plug in the speaker and a reactive load to balance it?

Fill in all the other combinations; I know they exist but my question remains.

[Jay]

Here's a question grounded in profound ignorance. Please not to laugh, I seek enlightenment. For the sake of brevity I will phrase it this way:

If you have a single impedance amp ( say 8ohm) and a 16 ohm speaker, could you not plug in the speaker and a reactive load to balance it?

Fill in all the other combinations; I know they exist but my question remains.

You can parallel your 16ohm speaker with a 16 ohm equivalent reactive load to provide the required 8 ohm. Your reactive load will need to be able to handle half the power and of course that consumed power is expressed as heat, not volume

[Slowy]

Here's a question grounded in profound ignorance. Please not to laugh, I seek enlightenment. For the sake of brevity I will phrase it this way:

If you have a single impedance amp ( say 8ohm) and a 16 ohm speaker, could you not plug in the speaker and a reactive load to balance it?

Fill in all the other combinations; I know they exist but my question remains.

You can parallel your 16ohm speaker with a 16 ohm equivalent reactive load to provide the required 8 ohm. Your reactive load will need to be able to handle half the power and of course that consumed power is expressed as heat, not volume

So it becomes an attenuator?

[Jay]

Here's a question grounded in profound ignorance. Please not to laugh, I seek enlightenment. For the sake of brevity I will phrase it this way:

If you have a single impedance amp ( say 8ohm) and a 16 ohm speaker, could you not plug in the speaker and a reactive load to balance it?

Fill in all the other combinations; I know they exist but my question remains.

You can parallel your 16ohm speaker with a 16 ohm equivalent reactive load to provide the required 8 ohm. Your reactive load will need to be able to handle half the power and of course that consumed power is expressed as heat, not volume

So it becomes an attenuator?

In a way I suppose. Not sure how it would affect the amp's frequency domain.

[NippleWrestler]

The 2x12 resto is complete.

I got this with the Mesa boogie I bought. It was made by the sellers old bassist from solid rimu. Finger jointed, with big gaps in between, and the internal bracing is made of rimu architrave which weighs about 600 kgs but makes it "reassuringly heavy".

It wasn't bad... It worked, it just looked like shit with loose flabby bright red grille cloth and a back made of bendy plywood covered in red vinyl. Fetching.

I sanded it back, stained it walnut and finished in poly but kept the scratches and shit in there for the 'character'. Then I went to the fabric store and picked up this fake velvet to use as a grille cloth, trying to keep the thing all walnut, black, and bronze.

1000040872.jpg (356.18 KiB) Viewed 3567 times

Made a new back from 18mm plywood with a new locking jack. Turns out the recess is 15mm at one and about 9mm at the other. I did what I could tm flatten it out but the back does protrude somewhat.

Speakers are a v30 and a 1987 g12 m70. I know people hate the m70 but man, it sounds great here and maybe due to the solid wood but it's very punchy and growly, I was really enjoying it earlier on my quick jam.

The old handles were cabinet handles. The dude carved out the recess for where their bolts used to be. I have handles coming but drilled the old crap out and filled it in with black epoxy

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And the period-correct features

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[Jay]

Came out really well

[jeremyb]

Classy!!! Well done!

[Cdog]

IMG_20250101_131158836.jpg (353.06 KiB) Viewed 2439 times

Well, it passes functional tests... Will see if it turns into a useful project.
It's a Class D amplifier... AliExpress

[griff]

The 2x12 resto is complete.

I got this with the Mesa boogie I bought. It was made by the sellers old bassist from solid rimu. Finger jointed, with big gaps in between, and the internal bracing is made of rimu architrave which weighs about 600 kgs but makes it "reassuringly heavy".

It wasn't bad... It worked, it just looked like shit with loose flabby bright red grille cloth and a back made of bendy plywood covered in red vinyl. Fetching.

I sanded it back, stained it walnut and finished in poly but kept the scratches and shit in there for the 'character'. Then I went to the fabric store and picked up this fake velvet to use as a grille cloth, trying to keep the thing all walnut, black, and bronze.

1000040872.jpg

Made a new back from 18mm plywood with a new locking jack. Turns out the recess is 15mm at one and about 9mm at the other. I did what I could tm flatten it out but the back does protrude somewhat.

Speakers are a v30 and a 1987 g12 m70. I know people hate the m70 but man, it sounds great here and maybe due to the solid wood but it's very punchy and growly, I was really enjoying it earlier on my quick jam.

The old handles were cabinet handles. The dude carved out the recess for where their bolts used to be. I have handles coming but drilled the old crap out and filled it in with black epoxy

1000040874.jpg

And the period-correct features

1000040877.jpg

I love the M70s. I have two from Bg from '83. I mix them with T75s also from the 80s. It's a punchy tight combination

[jeremyb]

Well, it passes functional tests... Will see if it turns into a useful project.
It's a Class D amplifier... AliExpress

Ooooh interesting! I have been having thoughts about building a stereo power amp in a 2x10 combo for use with the simplifier or any other preamp style pedal, with balanced inputs etc...

[Cdog]

Well, it passes functional tests... Will see if it turns into a useful project.
It's a Class D amplifier... AliExpress

Ooooh interesting! I have been having thoughts about building a stereo power amp in a 2x10 combo for use with the simplifier or any other preamp style pedal, with balanced inputs etc...

Yeah I have been thinking similar things... about making an equivalent of the EH pedal-board power-amps.
Second attempt, bought some a year ago which were DOA.

[PaulWD]

Friends dsl40. Channel switching was faulty. A common problem I read. My fix is to convert to a jtm50 black flag.

Before
IMG_20241110_131753.jpg

About half way. Recycling output daughter board. Ill mount the power bits on another board.
IMG_20241202_200928.jpg

Want to finish this in a week or two so I can get on to another conversion before Xmas.

Working at the pace of a racing glacier I managed to test this today before sorting out the negative feedback circuit. It's a fierce (and temporarily noisy) beasty.

20250112_173339.jpg (3.09 MiB) Viewed 2106 times

Nearly all parts were ex what I had on hand except new pots, sockets and knobs. I figure I have about $100 into it for parts. I ran out of blank phenolic board some time ago and figured I'd start using up my tag board stocks.

[murky]

Sooooo…. when someone offers you a cheap 70’s (?) Vox Buckingham…..just say no…..

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[codedog]

Sooooo…. when someone offers you a cheap 70’s (?) Vox Buckingham…..just say no…..

IMG_0130.jpeg

Oh god... I should check when I last had my tetanus booster.