OT Needed For 60's Gibson GA-6 Amp....

[zozoe]

Greetings~ Upon bringing my amp to my guy to see why my prized '55 GA6 sounded anemic, I was dismayed to find out that the amp was getting power from only 1 of the 2 6V6's. He's a great tech, and it's akin to bringing a Harley to a lawnmower repairman, but the upside is that I bring him lawnmowers, & I invariably walk away with a Harley...

His age olde intuition led him to check first for a measurement across pins 3 of the 6V6's, & it was a big fat nothing. The power iron & power section are fine & the amp powers on & plays,,,, but.....

So, according to him, I need a new output tranny; he said something about one with an 8K ohm center tap feeding the 8ohm speaker... As we're all aware, there were a handful of different GA6's, but this one's the peach,, much like my GA20 + 20T,,, & I'd like to know what & where to get the properly rated one, and what the up or downsize would be of getting something that's 'close' & not exactly 8K?

Here's the vital pics, & thnx in advance!!

Kenny 🕉

[Stevem]

A Hammond model 1751A is made for Gibson amps running 6V6 output tubes.

It's a 8K 15 watt item and has the added plus of having a 4 and 16 ohm output tap besides the needed 8 ohm.

Before you use any replacement output and mount it back on the speaker be sure to epoxy over the wires coming out of it such that they can't move around.

Over the years I have replaced output transformers in like 5 to 7 of these GA-6 amps and in atleast 3 of those repairs just like yours one side of the primary was open.

In these 3 transformers that failure came about due to wires moving around enough to break the extremely fine wire that those 3 primary wires coming out of the transformer attach to.

The epoxy retaining the wires will prevent that!

Mercury magnets makes a top shelf replacement for your amp, and it's priced as such at 99 USD, yikes!!!.

I can get a 40 watt OT for that price!

[thetragichero]

if you want something closer in age to your amp instead of brand new and don't mind that it doesn't have open end bell covers, the output transformer from a hammond ao-43 organ chassis could work here

[FUCHSAUDIO]

A Fender Deluxe output (or someones equal for it) should work fine.

[zozoe]

Great,, So, do you sell one Fuchsaudio? Thnxॐ

[FUCHSAUDIO]

Normally I would, but we're in the midst of some supply challenges and cannot spare one at the moment.
Our Blackjack output woulda been perfect... , sorry.

[zozoe]

Thnx Andy~
🕉

[Stevem]

Supply challenges are off the wall!!

We needed over 800 pieces of a filter cap for a item we are building , we found enough of them and ordered them, we paid for them and they where shipped out.

After they did not arrive we found out that the electronics house we bought them from had the shipment stopped at a regional Fed Ex location and turned around to go back to them.

After much detective work and a sales person on the inside of this supply house we found out that our shipment was sold to a builder who offered a much higher price for these caps then the standard price that we paid.

It's cut throat times out there right now, but just wait until food shortages start to take place!

[Phil_S]

You should be able to locate a Hammond replacement OT. I think yours is 8K:8Ω. It's up to you to verify the specs. Here is the Hammond line of transformers https://www.hammfg.com/electronics/tran ... ferer=1101 I'd say anything near 8K primary and 15W rating is OK. Multiple secondaries will give you flexibility on speaker choice should you decide to make a change.

[johnnyreece]

This one might do the trick: https://www.ebay.com/itm/165513753373?h ... SwT29imKdc

This one is a little higher power (and has a four hole mount, which you may not want): https://www.ebay.com/itm/165445319317?h ... SwkcleQqrI

[imjonwain]

You can go directly to Matt's website Musical Power supplies too. He sells them direct a little cheaper and has more options. He'll also wind you whatever you want (within reason) for not much more than the standard prices. I've been really happy with his parts.

https://www.musicalpowersupplies.com/products/

[thetragichero]

i will add my glowing review for musical power supplies. maybe not nearly the selection of ready-to-order transformers that classictone had but they've certainly filled a big hole (good quality stuff for very little money)