Mojotone Amp Kits

swivel

Country Gent
Silver Member
May 13, 2018
2,392
PNW
I bought two of the imported Weber transformers years ago to use on experimental/prototype amp builds. Both failed.

I love Weber speakers to death but I don’t use any of their amp building supplies. There’s no reason not to use Hammond or Heyboer when they’re both reasonable priced.

If you wanna slurge, I agree with Tavo. Spend it on the output transformer.
Yeah, my understanding is they have better trannies now. Still ....I think the Mojo kits are better, due mainly to some small things, like the IEC socket does't fit firmly in the chassis cutout and pops out or is loose etc. for the Weber. The caps/resistors look real cheap also. But if the savings was enough I could go for a Weber kit.
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
I bought two of the imported Weber transformers years ago to use on experimental/prototype amp builds. Both failed.

I love Weber speakers to death but I don’t use any of their amp building supplies. There’s no reason not to use Hammond or Heyboer when they’re both reasonable priced.

If you wanna slurge, I agree with Tavo. Spend it on the output transformer.
Good tip. I can source Hammond and Heyboer up here and not pay to ship iron from the eastern seaboard.
 

Powdog

Gretschie
Mar 15, 2012
361
Cool,CA
The company that manufactured the Classic Tone line of transformers, Magnetic Components, was liquidated and their tooling sold off (purportedly to Heyboer). Triode USA advertised that they were gonna pick up the ball and sell MC design trannies under a new name but as far as I can see that never happened. In fact, they’re recommending Hammond. Classic Tone is unobtanium unless you can find old stock somewhere.
1675803517801.jpeg
 

afire

Friend of Fred
Feb 12, 2009
6,405
Where the action is!
I also substituted Mallory 150s for the Orange Drops, but that is my personal tone choice.
I once replaced Orange Drops with Mallory 150s in a tweed Deluxe clone and I thought it was an improvement. But I'll admit that it's hard to ever be certain how much of the difference is coming from your ears vs. your expectations.
With a BOM or some time you can make your own parts list and save some $ and choose some parts you'd rather have..
My first tweed was a kit, but that's how I did a few after that. With how readily available parts and information are, it's not hard to do. But there's always value to convenience too.

For kits, Marsh is not a bad option, especially if it's your first (and maybe it isn't, I don't know). He offers some degree of support if you run into any challenges.
You can get a complete combo kit with cab and speakers for the same amount as the head only from Mojo. And it comes stock with Heyboer transformers. For $75 you have the option to upgrade to a Mercury Magnetics OT. For another $50 you can get the cabinet lacquered. Unless you're dead set on a head only, Marsh seems like the better deal.
 

TV the Wired Turtle

Gretschified
Double Platinum Member
Jul 25, 2009
14,988
Sandy Eggo
I remember Mercury Magnetics were the mob to by transformers from about 10 years ago. Do you rate them?

I think its important to use Mercury Magnetics if you must have a specs nailed down for a replication build. In the case of my 63' Blondeshell amp builds (6G6-b bassman amp clone minus bass side + reverb), there is no one else producing a Tone Clone transformer of this carefully crafted OT of the 6G6-B bassman, so to use anything else, is less than ideal :) Same deal w the EH-185 prewar Gibson octal tube amp clone I build, the Moonshine '39. Again MM replicates a Tone Clone set for this amp build. I have great respect for this so cal transformer company thats been in the biz since the 50s, although I'd prolly jump ship if Schumacher started offering production replicas again.
moonshine_4_64449108_1024x1024.jpg

As my old pappy used to say, there's a time to do it, and a time to do it right. :)
Although Im not building a kit/hobby amp, I manufacture booteeky amps
so I just wasted a lot of air on why I value Mercury Magnetics :) :)

5661296cdaf99.jpeg
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
I think its important to use Mercury Magnetics if you must have a specs nailed down for a replication build. In the case of my 63' Blondeshell amp builds (6G6-b bassman amp clone minus bass side + reverb), there is no one else producing a Tone Clone transformer of this carefully crafted OT of the 6G6-B bassman, so to use anything else, is less than ideal :) Same deal w the EH-185 prewar Gibson octal tube amp clone I build, the Moonshine '39. Again MM replicates a Tone Clone set for this amp build. I have great respect for this so cal transformer company thats been in the biz since the 50s, although I'd prolly jump ship if Schumacher started offering production replicas again.
moonshine_4_64449108_1024x1024.jpg

As my old pappy used to say, there's a time to do it, and a time to do it right. :)
Although Im not building a kit/hobby amp, I manufacture booteeky amps
so I just wasted a lot of air on why I value Mercury Magnetics :) :)

5661296cdaf99.jpeg
The Mercury Magnetics output transformer is nearly twice as spendy as the Hammond, but it's not a deal breaker. Thanks for the tip!
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
I once replaced Orange Drops with Mallory 150s in a tweed Deluxe clone and I thought it was an improvement. But I'll admit that it's hard to ever be certain how much of the difference is coming from your ears vs. your expectations.

My first tweed was a kit, but that's how I did a few after that. With how readily available parts and information are, it's not hard to do. But there's always value to convenience too.

For kits, Marsh is not a bad option, especially if it's your first (and maybe it isn't, I don't know). He offers some degree of support if you run into any challenges.
You can get a complete combo kit with cab and speakers for the same amount as the head only from Mojo. And it comes stock with Heyboer transformers. For $75 you have the option to upgrade to a Mercury Magnetics OT. For another $50 you can get the cabinet lacquered. Unless you're dead set on a head only, Marsh seems like the better deal.
Can also get it without cab and speakers, and upgrade to a Mercury Magnetics output transformer. Not a bad deal at all... Thanks!
 

swivel

Country Gent
Silver Member
May 13, 2018
2,392
PNW
I once replaced Orange Drops with Mallory 150s in a tweed Deluxe clone and I thought it was an improvement. But I'll admit that it's hard to ever be certain how much of the difference is coming from your ears vs. your expectations.

My first tweed was a kit, but that's how I did a few after that. With how readily available parts and information are, it's not hard to do. But there's always value to convenience too.

For kits, Marsh is not a bad option, especially if it's your first (and maybe it isn't, I don't know). He offers some degree of support if you run into any challenges.
You can get a complete combo kit with cab and speakers for the same amount as the head only from Mojo. And it comes stock with Heyboer transformers. For $75 you have the option to upgrade to a Mercury Magnetics OT. For another $50 you can get the cabinet lacquered. Unless you're dead set on a head only, Marsh seems like the better deal.
I like Marsh a lot. I buy my waxed cotton push back wire from them only, they have the right stuff. They are small, just him and his wife I think.... They answer emails right away.
 

afire

Friend of Fred
Feb 12, 2009
6,405
Where the action is!
I like Marsh a lot. I buy my waxed cotton push back wire from them only, they have the right stuff. They are small, just him and his wife I think.... They answer emails right away.
Again without knowing the OP’s experience, I have no idea whether support is valuable. If it is, then I think Marsh is a good option
 

GretschPlayer101

Gretschie
Oct 7, 2011
447
Los Angeles
One post I think said maybe buy a used Tweed clone and make changes to it yourself to the parts because the Mojo kits do cost a lot.

In 2016 I bought a Tweed Deluxe copy off Aliexpress and it has been a very good amp. I don't see many off AE much now but a website called Made In China has many a Tweed for sale. In fact I bought a Tweed Champ clone from MIC about 5 years ago as a small bedroom amp. Works and sounds great. Wish I had bought the head and cab version because I never had a stack amp before and it would be cool to have.

So far both Tweeds have been reliable and sound good. I like both but thinking one day make a project out of it and replace parts. I can learn how to work on amps and also improve upon them even tho in stock form they are good.

A few years ago on eBay you would see a lot of Reverb units for a reasonable price and people would wonder how for those prices? Americans would order a bunch from MIC and have a custom name ordered to be placed on them then resell them. People would also resell Tweed amps that way.

Now if you want to build a kit for fun and learning purposes then go that way. If you just want a Tweed at a good price maybe the MIC way to go and mod it yourself.
Mine are solid pine wood, not particle board cab. They are hand wired point to point.

I know a lot about guitar parts and tech, but amps not so much, so i can't vouch for the quality of parts, but I can say the price was affordable and the sound is good and the cab is good.

I think this may be a good way to go.

Here is the Champ clone. I put a Fender badge on but no I am not trying to sell it and fool people, I would never do that, it is for myself for fun.

Mine were not lacquered but I did lacquered the Deluxe myself and although it didn't turn out as "good" as the real deal it did turn out looking relic'd. It turned out to be the accidental relic or vintage amp look. I didn't put a badge on it.


IMG_20230109_004022929_HDR.jpg
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,326
France
I bought two of the imported Weber transformers years ago to use on experimental/prototype amp builds. Both failed.

I love Weber speakers to death but I don’t use any of their amp building supplies. There’s no reason not to use Hammond or Heyboer when they’re both reasonable priced.

If you wanna slurge, I agree with Tavo. Spend it on the output transformer.

I agree completely...

A+!
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
Of course, the Rob Robinette AB763 Blackvibe would also scratch the itch, tho I'd have to source all the components myself. It's the normal channel of a '63 Blackface Vibroverb, with no reverb or vibrato. Decisions, decisions.....
 
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pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
I bought two of the imported Weber transformers years ago to use on experimental/prototype amp builds. Both failed.

I love Weber speakers to death but I don’t use any of their amp building supplies. There’s no reason not to use Hammond or Heyboer when they’re both reasonable priced.

If you wanna slurge, I agree with Tavo. Spend it on the output transformer.
Thanks for the tip. I checked out the parts list for the Mojo kits, and with the exception of the 2W metal oxides in the power filtering, all the other resistors are 1/2W carbon comp, even at the screen of the 6L6s. Would probably replace all these carbon comps with metal film, and higher wattages at the screen.
Any thoughts on this? @hcsterg @TV the Wired Turtle, @markeebee.. what about you guys?
 
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hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,326
France
For 6L6GC, I often go for 5W ceramic resistors : the white 1K 5W below, for a 75W quartet.

1676231162061.png

For EL84/6BQ5, I use 2W film resistors (carbon or metal film) : the green 100R below, for a 10W duet.

1676231323149.png

But it's me, OK ? 😁 ;)

A+!
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
For 6L6GC, I often go for 5W ceramic resistors : the white 1K 5W below, for a 75W quartet.

View attachment 201735

For EL84/6BQ5, I use 2W film resistors (carbon or metal film) : the green 100R below, for a 10W duet.

View attachment 201737

But it's me, OK ? 😁 ;)

A+!
Merci, mon ami. The 1/2 W resistors that come with the kit seem a bit underrated for the screen, and I've heard nothing good about carbon composite resistors in general...except that they're inexpensive, of course.
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,326
France
Merci, mon ami. The 1/2 W resistors that come with the kit seem a bit underrated for the screen, and I've heard nothing good about carbon composite resistors in general...except that they're inexpensive, of course.

You welcome, @pmac11 ! :)

Well, Carbone Composite resistors looks like this - at least for the most known US-made ones :

1676237884615.png 1676237919301.png 1676238113170.png

I don't find the Carbon Composition resistors inexpensive... As nearly all Vintage amps used them (as well as military transmission equipment) they are sought after now, and even reissued at a fairly superior cost than precision resistors... But maybe you were speaking about Carbon Film resistors, which - like Metal Film now - are much less costy than Carbon Comp today.

Well, OK : I speak for EU - Maybe it's not true in USA, though !

The inconvenience with time passing-by of the Carbon Composition resistor is that they tend to become more and more "Creaky-Hissy-Noisy", so you may need to replace them (think 100K plate resistors of old Fender amps preamp stages, for example) in order to "recover silence".

A good choice is then to go for Carbon Film, which are silent and more stable. It's what I use in priority in my amp builds, but the choice in values and tolerances is often not as large as the Metal Film resistors.

So you can use also Metal Film, which is even better in terms of noise and stability at the same cost (or nearly), but some of these resistors may be responsible of "hardness" or "harshness" in tone, because under transients, they tend to act like a combination of micro-diodes or even give some kind of battery effect... Well, at least this is from an Audiophile standpoint, and I'm not sure that it is soooo crucial for guitar amps, OK ? 😁;)

A+!
 

pmac11

Country Gent
Mar 4, 2018
3,785
Toronto, Ontario
You welcome, @pmac11 ! :)

Well, Carbone Composite resistors looks like this - at least for the most known US-made ones :

View attachment 201751 View attachment 201752 View attachment 201754

I don't find the Carbon Composition resistors inexpensive... As nearly all Vintage amps used them (as well as military transmission equipment) they are sought after now, and even reissued at a fairly superior cost than precision resistors... But maybe you were speaking about Carbon Film resistors, which - like Metal Film now - are much less costy than Carbon Comp today.

Well, OK : I speak for EU - Maybe it's not true in USA, though !

The inconvenience with time passing-by of the Carbon Composition resistor is that they tend to become more and more "Creaky-Hissy-Noisy", so you may need to replace them (think 100K plate resistors of old Fender amps preamp stages, for example) in order to "recover silence".

A good choice is then to go for Carbon Film, which are silent and more stable. It's what I use in priority in my amp builds, but the choice in values and tolerances is often not as large as the Metal Film resistors.

So you can use also Metal Film, which is even better in terms of noise and stability at the same cost (or nearly), but some of these resistors may be responsible of "hardness" or "harshness" in tone, because under transients, they tend to act like a combination of micro-diodes or even give some kind of battery effect... Well, at least this is from an Audiophile standpoint, and I'm not sure that it is soooo crucial for guitar amps, OK ? 😁;)

A+!
My education on carbon comp resistors comes primarily from this YouTuber. Interestingly, he shares many your misgivings about Mesa Boogies.

 
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