Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Esquirefreak on October 27, 2021, 01:24:22 pm
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Ey! Hope everyone's having a nice wednesday!
I scored this '66 SR a couple of weeks ago. Due to one of my arms went numb from some nerval issues, I haven't gotten around to start the maintenance and general service. I've ordered some JJ and F&T caps for the power supply. And the k-bypass caps, dropping R, screen R and so on will be swapped for some new sturdy ones.
I payed $150 for it, and apart from the things mentioned below, it appears to be unmolested. Some jackass chopped the cab to make 2*10, but I'll probably build a head cab for it. So still a fine deal on the price.
However... I noticed some things and would hope that someone with a lot of knowledge will chime in.
This is an export model sold in Sweden sometime during 1966, and during that time Sweden had regulations prohibiting the use of capsuled mains transformers. So Hagström (the general supplier for the swedish market) had to swap out all the PTs to be able to sell the legally. They only did this the first couple of years of importing '65-'66.
Another thing that seemed really off, was that the primary side of the PT wasn't fused at all. Instead, they fused the sec. HT winding and then put in an additional fuse for the B+. I rewired it so that instead, one of the fuses secure the primary side and then kept the HT fuse as well. It'll do for now :icon_biggrin:
I'm actually planning to swap out the trannie for a Hammond 290DEX when my wallet will allow it. I have one of those in my 6G4 clone and am very pleased with its performance.
The strange resistor by the reverb driver - is that something fender ever did at the factory? Or is it yet another weird thing made by a group of swedes? I assume its acting like a plate resistor...
/Max
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Pics
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Pics
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The mysterious PT...
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Last pic.
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I've never seen that resistor before.
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I was almost certain that was the case. It only measures 1k (although with the resistor still in circuit), so I wonder what they tried to achieve by putting it there... :dontknow:
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Probably trying to protect the reverb OT.
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You paid $150? I’ll give you $250 plus shipping. Probably not worth your time to repair :icon_biggrin: :l2:
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When you say ‘capsuled’ transformer. You mean the bells covers? Wouldn’t it be easiest for Hagstrom to just remove the bells rather than swap the tranny entirely?
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Yeah, that thought occurred to me as well. Not sure what their aim was. They sure hacked the chassis in a not so good looking manner in the making...
But nonetheless, the price was right and i'm sure it'll be a nice player grade amp :icon_biggrin:
/Max
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The strange resistor by the reverb driver - is that something fender ever did at the factory? Or is it yet another weird thing made by a group of swedes? I assume its acting like a plate resistor...
It is probably meant to drop voltage on the reverb transformer and protect it like sluckey stated. I would understand it as an own voltage node if there was a cap connected Furhermore the resistor should be a power resistor since It looks overheated.
/Leevi