Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: smackoj on June 05, 2016, 07:19:42 pm
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I found and bought this Traynor YGL-3 MkIII amp in Longmont, CO yesterday. I believe it dates to 1976. It works but has a lot of hum and the occasional snap, crackle and pop. The 'first look' visual inspection shows a mostly unmolested chassis for a SS rectifier, four EL34 output tube beast that must have been Traynor's competitor for the blackface Twin Reverb. The power cable has been chg'd to a 3 prong and the power filter caps have been replaced with the low cost Xicon variety. I don't really see many changes but there is a major change in the output parts. The orig. OT has been removed and replaced with what appears to be a Classictone 40-16823 tranny. Unfortunately that is a 2 output tube PP OT and this amp has four 6CA7 output tubes. Some 'tech' ran a short jumper wire between the pin 3 of the two sets of 2 output tubes. Then they used the normal output connection with a blue wire and a brown wire from the two sets of output tubes to the primary of the OT. Also, the two orig. speakers were replaced with a 16 ohm Peavey and a 8 ohm Fender (italy). That obviously does not seem like a good ohm application but they may have wanted to try and "match up" the 2 output tube OT with four power tubes and 2-12" speakers? I would like to have any/all suggestions for what OT I should consider purchasing for this amp? I am not a big fan of Merc Mag OT's mostly due to cost.
Thanks mucho amigos
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The orig. OT has been removed and replaced with what appears to be a Classictone 40-16823 tranny.
I can't find any info on that OT. Are you sure about the number?
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there is no name badge on the OT. It is black all over with metal end bells and these numbers:
P-TF22899
40-16823
166-0249
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That OT is a replacement for a Fender Twin Reverb. It's rated for 100W, 2KΩ:4Ω. Should be a fine replacement in that Traynor amp.
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FWIW: Dan Torres suggests a power supply upgrade: "Inside Tube Amps", p247, ff. KOC might have some ideas in his TUT series.
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"replacement for Twin Reverb" I thought a 4 output tube amp had 4 wires to connect to the four power tubes? This tranny only has a blue and a brown wire from two sets of two power tubes. Is that the right primary hookup for a 4xEL34 tube output? again, I thought each power tube got it's own wire from tube to the OT? And I only see a green and black wire on the secondary side so I don't know where the other tap for 2 or 4 ohms would be? I haven't removed the OT so maybe someone cut wires off really short and I'm not seeing them? I will look closer. thanks
I am having trouble with my home wifi so I may not get to read or respond on a tight schedule. sorry.
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I thought a 4 output tube amp had 4 wires to connect to the four power tubes?
No. Why would you think that?
This tranny only has a blue and a brown wire from two sets of two power tubes. Is that the right primary hookup for a 4xEL34 tube output?
Yes. That's exactly what the schematic shows.
again, I thought each power tube got it's own wire from tube to the OT?
No.
And I only see a green and black wire on the secondary side so I don't know where the other tap for 2 or 4 ohms would be?
That's exactly what the Traynor schematic shows. That amp was set up to run 2 8Ω speakers in parallel. 4Ω total. No provision for 2Ω or any other speaker impedance.
I haven't removed the OT so maybe someone cut wires off really short and I'm not seeing them?
No. There were only 5 wires on the Traynor original. Red, blue, brown for primary, green, black for secondary. Exactly the same on the replacement. The replacement is an excellent choice for that amp.
I will look closer.
Take a look at the schematic. It's in Hoffman's schematic library. Link at bottom of this page.
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Here's some interesting mod info. Might be some of Torres recommendations .
http://studioboytimes.tumblr.com/post/145078185439/traynor-ygl-3-upgrades-mods?is_related_post=1 (http://studioboytimes.tumblr.com/post/145078185439/traynor-ygl-3-upgrades-mods?is_related_post=1)
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Those Xicon caps are as good as anything else. Diligent of the tech to squeeze them into their original clamps and maybe chose caps that fit the ring - and that he didn't harvest the mustards.
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It plays, right? Track down the hum and sputter first and then think about upgrades/mods.
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hi; sorry SL, I just always thought that 4 tube output had a separate wire to the primary for each tube. I never owned or worked with a 4 banger so I obviously thought wrong. I couldn't read the schemo because my internet went down. I will download a copy now while I have the chance. thanks as always for your help.
I probably won't do any mods. at least not at first. I want to get her running quiet and strong first and see if I like what it came with stock. :icon_biggrin:
....and about those 'mustard caps' I never had those before either so I'm excited to hear the mojo workin'.
thanks to one and all. smacko jack
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post previous script. "why would you think that?" about the output tubes each having a wire to the OT. I remember now why I thought that Steve. The fact that the tranny had been replaced and instead of have two 8 ohm speakers in parallel making the customary 4 ohms, there is a 16 ohm and an 8 ohm set of speakers wired in series making an oddball load. So, I concluded that the tranny was wired in in odd fashion and the strange speaker hookup was there to adjust for the oddball tranny hookup. It seems as though someone just hacked together the 16 and 8 ohm speakers in series for some unknown reason but it led me astray on what I thought was going on. Live and learn as folks like to say.
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I think the OT was replaced by a competent technician. The odd speaker configuration probably came later by a different person.