Fender '57 Mini Twin

Tube or solid-state, this section goes to eleven!
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JiM
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Post by JiM »

I don't know where to post that, as we don't have a "pimp my toy amp" section ...
Dear moderators, feel free to move to "amplifiers" if it's more appropriate.[/i]
So, i've received this cute tiny amp yesterday ... and i couldn't resist, i've opened it today. :slap:
Some gutshots (from someone else) : http://www.bustedgear.com/repair_Fender ... ion_2.html

There is a single 4558 opamp as preamp (only one half used ! :shock: ), and a 0.5W chipamp, more or less similar to a LM386, as power amp. It's a twin, so there's two 2" louspeakers, in series.
The tone control is interesting, and very similar to the "contour" that i like so much in my old Valvestate : it goes from mid-cut/hi-boost to hi-cut, with mostly flat and slight hi-boost in between.

The clean sound is great for the size, and suprinsingly loud, but the distortion is quite harsh : it's indeed due to a pair of diodes to ground ! The classic tricks should apply : using LEDs as clipping diodes, maybe moving them to the feedback loop of the gain stage, using the second half of the opamp as a buffer before the tone control, etc.

Maybe i'll try to add a tube to it someday ... :mrgreen:
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The headphone jack wiring is not accurate : <br />the load resistor and inductor are in the circuit only for the headphones.
The headphone jack wiring is not accurate :
the load resistor and inductor are in the circuit only for the headphones.
I only give negative feedback.

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lolbou
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Post by lolbou »

Cool, thanks for the schem. :D

I would add an external speaker plug to play on a big cab. I did it on my mini Orange Crush, and it's nice...

Oh, and it does seems appropriate to me in the Amplifiers section. Let's move on...
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ansil
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Post by ansil »

the "chip amp" is the same as the one in the marshall ms-2 posted all over here and the net as well. it works quite well for driving a larger speaker. instead of diodes to ground what about using the second opamp to od that and then a blend knob to blend in the two. take a small camera flash transformer and drive the piss out of it with a single opamp and dump the output into the front end as a recovery stage and check that out. add some feedback to it. you could definately make it into a little tube head.

ed

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Kilby
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Post by Kilby »

Would the transformer in those awful energy efficient (compact fluorescent) bulbs be suitable ?

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ansil
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2 bogner ecstasy preamps [both for personal use]
10 marshall guvnor mods and builds
100 jungle kat boosts
too many penguin love's to count.
5 blues pearl purplexed
dozen tube screamer fulldrive whatever you call them variants

hell i can't type this long it will piss off people what can i say i have been doing mods on toyz appliances gear sex toyz computers and such for 27 years. i started when i was 6 taking stuff apart.
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Post by ansil »

thats a good idea would probably be noisy though but i am speculating i have a dead one will have to check it out.

ed

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Post by lolbou »

ansil wrote:take a small camera flash transformer
Hey Ed, any specifications on these (windings, impedance, whatsoever)? Just curious for some other purposes...
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- Uh, no, I'm a mocker.

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Post by Solidhex »

Ah cool

I have one of these. I like the tone knob too. Interesting to see what's inside.

--Brad

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Post by HoggYBhoY »

any idea the spec of those 2 inch speakers?

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ansil
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my favorite amplifier: my hughes and kettner blue 30r
Completed builds: 3 jcm 800 builds
4 vintage plexi builds
2 bogner ecstasy preamps [both for personal use]
10 marshall guvnor mods and builds
100 jungle kat boosts
too many penguin love's to count.
5 blues pearl purplexed
dozen tube screamer fulldrive whatever you call them variants

hell i can't type this long it will piss off people what can i say i have been doing mods on toyz appliances gear sex toyz computers and such for 27 years. i started when i was 6 taking stuff apart.
Location: cleveland tn
Has thanked: 15 times
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Post by ansil »

I know it's 7 years too late I never actually received a reply about this in my email sorry the Transformers all very depending on manufacture. however if you're looking to make like a Tycho brahe octave box it can be done

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