Traynor TS-15 Mods

[CoolMic]

I got another Traynor TS-15 so I can rebuild one and keep playing the other.

I have a few questions. First off the amp is very dark, boxy and has some low end boom that I don't like.

1. Would reducing the 100nF cap at the input down to 68nF reduce bass going into the amp?
Traynor did make this change on later/larger amps in this series.

2. The entire preamp seems to be an opamp boost pedal with a tone stack on the end.
What effect would changing the 47pF gain pot bypass cap have?

3. What does the 270nF cap in the power section do? How about the 47nF cap?
Other Traynor amps in the TS series have the 47nF cap but none of the other designs have a cap in the same position as the 270nF cap.

4. Would changing the opamp to OPA134 have any noticeable affect on the sound?

Thank you in advance for any help.

[g1]

You can't just isolate single components in circuits that are otherwise not identical.
The input cap has to do with the other caps and resistors around it, do the other amps have the 100p to ground?
The gain pot bypass cap will affect the frequency response somewhat.
Do the other amps use the TIP100 and 105 output devices?  Those caps in the power amp are for stability.
Not sure if changing the IC would have any benefit. 
Sometimes putting modern parts in old circuits makes them worse, as they were designed around limitations of parts.  For example, chips with better bandwidth or faster slew rate can make amps sound more harsh.

[Tassieviking]

If you want to mess with the amp then you should leave the power amp section alone.
The pre-amp is where the tone shaping happens.
The closest you should go to the power amp is the 100nF cap going into the power amp, that 100nF cap with the 100k to earth is a HPF filter that drops any frequencies below 15.9Hz. Change to a 10nF cap and the frequency is 159Hz, experiment if you like.
I would concentrate on the tone stack, changes there will affect your tone more.

Are you sure it is not the speaker itself that is dark sounding ?

[RookieRecurve]

If you want to mess with the amp then you should leave the power amp section alone.
The pre-amp is where the tone shaping happens.
The closest you should go to the power amp is the 100nF cap going into the power amp, that 100nF cap with the 100k to earth is a HPF filter that drops any frequencies below 15.9Hz. Change to a 10nF cap and the frequency is 159Hz, experiment if you like.
I would concentrate on the tone stack, changes there will affect your tone more.

Are you sure it is not the speaker itself that is dark sounding ?

This is great advice here.  With the amount of variables in an entire setup, mucking with a SS can be difficult. Small electrical mods to your guitar, pedals, and adding an extension to play with cabinets and speakers will likely produce better results.

Old post, I know, but it's really solid information for anyone considering modding a SS.