Montgomery Ward 35JDR8421
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stetterhawk
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Montgomery Ward 35JDR8421
I have a 1952/1953 Montgomery ward 35 jdr8421 that I was given many years ago from a 1940 era lap steel guitar player. It had very few hours on it when he gave it to me. I ended up working away from home for 20 years and this amp sat in the closet. I pulled it out last summer and cleaned it up and would like to put some hours on it. I need to go through the electrical end of it, cap change outs and any other bad electrical parts. I need a a wiring schematic diagram for this one. The tube lineup is 1x12ax7,1x6sn7,4x6v6's,1x12sj7 and 1x5y3 with a 15 inch speaker. I have looked at many schematic sites but never find the one for this amp. I have been told it might have been made by Daneletro. Any help?
Last edited by stetterhawk on Thu Mar 12, 2015 10:23 pm, edited 1 time in total.
Re: Montgomery Ward 35JDR8421
Sounds like a very cool amp . how bout sum pics?
Re: Montgomery Ward 35JDR8421
Sometimes you can find schematics that are the same under amps of a different name. Or at least very similar . I've found schematics for old off brand amps like that before
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Stevem
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Re: Montgomery Ward 35JDR8421
I have to look,but I may have a schematic, but unless you have burned up stuff in there just re- cap it and and for starters change out all the plate load and any other resistors that may have drifted more than 15% from what they should be.
As a general rule any 1/2 watt resistors that have more than 300 volts on them should be increased to a 1 watter, you also may just want to change out the resistors off of the input jacks, as at time when they go from moisture and just plain age they can add a ton of hiss to the amp!
Oh, also be sure to change out the cathode resistor for the output tubes and double up on the replacements wattage and if this amp does not have screen resistors on each output tube then adding such would be a good move in terms of keeping them alive also!
Also it can not be a 12sj7, it would have to be a 6sj7!
As a general rule any 1/2 watt resistors that have more than 300 volts on them should be increased to a 1 watter, you also may just want to change out the resistors off of the input jacks, as at time when they go from moisture and just plain age they can add a ton of hiss to the amp!
Oh, also be sure to change out the cathode resistor for the output tubes and double up on the replacements wattage and if this amp does not have screen resistors on each output tube then adding such would be a good move in terms of keeping them alive also!
Also it can not be a 12sj7, it would have to be a 6sj7!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
- David Root
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Re: Montgomery Ward 35JDR8421
5Y3 feeding 4x6V6 sounds a bit light on current to me. This amp's tube lineup is the same as the Danelectro Challenger EXCEPT the rectifier tube is a 5U4 in the Challenger.
Maybe someone changed that tube? 6V6 plate voltage on these '50s amps is typically around 320V, losing ~20V to the cathode resistor so net 300V or so.
If yours IS supposed to be a 5Y3, which I doubt, then don't put a 5U4 in it as it needs 3A 5V whereas the 5Y3 is 2A, you might very well blow that 5V winding with a 5U4. Use a 5R4 (NOT 5AR4), it needs 2A only and can supply 250mA DC, twice the 5Y3's capability.
Maybe someone changed that tube? 6V6 plate voltage on these '50s amps is typically around 320V, losing ~20V to the cathode resistor so net 300V or so.
If yours IS supposed to be a 5Y3, which I doubt, then don't put a 5U4 in it as it needs 3A 5V whereas the 5Y3 is 2A, you might very well blow that 5V winding with a 5U4. Use a 5R4 (NOT 5AR4), it needs 2A only and can supply 250mA DC, twice the 5Y3's capability.
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stetterhawk
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Re: Montgomery Ward 35JDR8421
just found pictures on another forum, This might help with the id until I get pictures of mine. mine looks just like this but in much better shape. the speaker on mine is in great shape so I look foward to hearing something this old. nothing has been tampered with, it is all original so would like to keep parts c/o to minimum. I also am going to check the tube numbers again just in case I screwed up or my my eyes are not as good as I claim them to be.
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stetterhawk
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Re: Montgomery Ward 35JDR8421
one more photo
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Stevem
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Re: Montgomery Ward 35JDR8421
No luck on schematic yet, it may take me into the weekend to dig mine up, sorry!
And I was wondering the same thing about the 5y3 powering 4 6v6s?
And I was wondering the same thing about the 5y3 powering 4 6v6s?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Montgomery Ward 35JDR8421
Interesting baffle board.
Too bad people let these things degrade so much in poor conditions.
But if you take your time and restore it, could be a very nice amp.
Looks like the OT has been replaced.
Too bad people let these things degrade so much in poor conditions.
But if you take your time and restore it, could be a very nice amp.
Looks like the OT has been replaced.
Tom
Don't let that smoke out!
Don't let that smoke out!
- Leo_Gnardo
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Re: Montgomery Ward 35JDR8421
5Y3 powering 4x6V6 = lotta compression maybe not such a bad thing for a steel amp. Or it could have been a panic replacement, gotta do the gig, anything that works more or less to see you thru. Same with the 12SJ7.
down technical blind alleys . . .
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stetterhawk
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Re: Montgomery Ward 35JDR8421
stevem I will wait Patiently
for any info you have, Structo the good news is mine looks a whole lot better than this, just used pictures from someone else's post on another forum until I can get pictures of mine.
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Stevem
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Re: Montgomery Ward 35JDR8421
I have a schematic for a GDR-8518A model which is 4-6v6, 2-12ax7, 6au6, 6sn7 and a 5y3 .
This model has bass and treble controls, does yours?
This model has bass and treble controls, does yours?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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stetterhawk
- Posts: 11
- Joined: Sun Feb 22, 2015 12:55 am
- Location: frozen tundra of Minnesota
Re: Montgomery Ward 35JDR8421
yes it does have bass and treble control and a 5y3 rectifier tube. It has a single 15 inch speaker I made a fat finger mistake on the size, need to reread my post sorry. That sounds like it might be the schematic
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stetterhawk
- Posts: 11
- Joined: Sun Feb 22, 2015 12:55 am
- Location: frozen tundra of Minnesota
Re: Montgomery Ward 35JDR8421
well I had not googled my amp number since last summer so I just did and the link below came up
https://reverb.com/item/392494-vintage- ... -combo-amp
This is the same as my amp , the one in the add is a 10 mine I would rate a stong 8.5 to 9 in condition. The add shows the tubes and underside of chassis
https://reverb.com/item/392494-vintage- ... -combo-amp
This is the same as my amp , the one in the add is a 10 mine I would rate a stong 8.5 to 9 in condition. The add shows the tubes and underside of chassis