Traynor mark 3 Amplifier (feedback resistor value)

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Traynor mark 3 Amplifier (feedback resistor value)

Postby Ampforya on Tue Mar 11, 2014 6:39 pm

I would like to find out the resistor values for the last capacitor in the amplifier before it goes to the output jack (negative feedback loop) It allows for a looser feel to the amp at lower volumes. Its a mod to increase gain from the power amp section to to speak, It has a 1 k resistor as stock.
Originally had a brown resistor rated at 10% within/ at 1kOhm.
I'm changing it to a 10kOhm at 1/2 a watt as that what I have from a full feedback loop kit which I ordered from Small bear electronics which had this value 1/2 watt and 1 watt.
http://www.guitarscanada.com/showthread ... 3-Mark-III


Thanks you,

Ampforya
Last edited by Ampforya on Wed Mar 12, 2014 11:57 pm, edited 1 time in total.
Ampforya
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby PeterS on Wed Mar 12, 2014 4:08 pm

resistor values for the last capacitor in the amplifier before it goes to the output jack (negative feedback loop)


? don't know where you mean?

That Edward amp link doesn't work for me.

I used a Mk3 for years, loved it, but the only mod that would make it useful for me now would be a way to lighten it by 30 pounds! :D
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby Ampforya on Thu Mar 13, 2014 12:12 am

:/ yeah its a built like a tank.
I updated the link at the bottom of my post, Its was on Guitars Canada so you'll notice it on that link.

i bought this amp the Mark 3-A head version so thats about 30lbs lighter already.
if you know anything about resistor values I have changed the NFB resistor to a 10kOhm from the 1k this gives the amp a higher amount of NFB send back into the input section.
So It sounds thick with less attack, as well as other compression factors that Im very much liking in the couple Fender style amps I have had modded this way.Mainly my VRC which Rod Evans pickup Guru/ added same type of mod as well with amazing results. Tighter bass and less highs because of the compression factors which come from this type of setting up of the NFB loop.

Thank you , I hope someone can help me figure if the 1/2 watt resistor is correct for this mod.
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby PeterS on Thu Mar 13, 2014 1:51 am

Changing the 1k to a 10k is making less nfb, not more.

The power rating of that resistor isn't critical, half watt will be fine, if it was me doing it I'd use whatever was the most convenient mechanically.

Funny, in that discussion thread there's a comment that it's amazing how this old piece of technology is still useful. In a way it's more useful now than it was back in the day: it's a great amp with pedals, without them it lacks versatility.

I had the head version also, I can't imagine carrying the combo. But if you want quality loud sound with lots of grunt, there's no alternative to big transformers. I remember trying a few Marshalls back in the day and finding them thin - compared with the Mk3 there's no bottom end.
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby Ampforya on Thu Mar 13, 2014 5:55 am

OK thanks for clearing that up!
I understand how it adds more gain!
Sounds like there is more going on than just focusing harmonic content when adding more NFB to an Amplifiers gain stages,
I believe there is some gain in the mid frequency and high frequency which gets attenuated by adding more NFB.

It would make sense its actually adding more gain in those frequencies now.
particularly compared to a Mark III's 1kOhm resistive function which gives it than pristine clean tone.
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby Ampforya on Thu Mar 13, 2014 6:04 am

OK thanks for clearing that up!
I understand how it adds more gain!
Sounds like there is more going on than just focusing harmonic content when adding more NFB to an Amplifiers gain stages,
I believe there is some gain in the mid frequency and high frequency which gets attenuated by adding more NFB.

It would make sense its actually adding more gain in those frequencies now.
particularly compared to a Mark III's 1kOhm resistive function.

Although I don't usually take it out it, now this amp is sounding more suited to what I like in a live setting.
Has a more bouncy feel to the notes, more tamed in the bass frequencies too.

(Its funny how not everyone has caught on to these big transformer amplifiers)

I have a 5 watt amp which has a HAmmond transformer and It sounds really great and clean at all volumes.

Goes into a bit of a nasty hum if I turn it up though. I might be posting some pics of the circuits tonight to get help with what type of Caps to use for the power filtering. These are some Iv seen which are pretty nice.
Mundorf MCap EVO in Oil, MCap400, MCap630, MCap Supreme, Supreme Silver/Gold/Oil and Jantzen Superior, Silver, Silver-Gold

Cheers,

Amp for ya :)
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Re: Traynor mark 3 Amplifier (feedback resistor value)

Postby Ampforya on Fri Mar 14, 2014 10:49 pm

As for replacing the Electrolytic's in my other amp.
Im sure some people will know which Caps will work best in this type of amp.
hers a link to the post I started a while ago, Thank you

viewtopic.php?f=11&t=89220&p=1031758#p1031758
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