Traynor YBA-1 to 1987 Conversion

[marshallnoise]

Got the new power cord installed and....


HELL YES!!!

VERY QUIET! Loving this amp.

Thanks for just letting me spitball on the web. Lesson learned though, definitely check the power cable. Most everyone where is using the Marshall style IEC conector, but in case you aren't, check the cable if you have 120hz buzz and the chassis stops the buzz.

[marshallnoise]

I spent a good amount of time with the amp and noticed a few things about the circuit.

First, the preamp section being opened up at the same rate as the power amp section is interesting. What I observe is that because of this dual feed into the two sections of the amp, the amp sounds kind of lifeless until the preamp section is opened up. By this point, it is practically unusable in a setting I am playing in (need relatively low volume). Because of this, the pedals I use for the majority of my coloring (Tube Screamer, Timmy clone) sound muffled and unclear. At crazy volumes, the amp comes alive. I think this is why everyone uses the PPIMV. So I am going to install it.

Second, channel II is unbelievably bright and channel I is VERY bassy and not clear until opened wide. I am going to convert the whole amp to 1986 specs. I have a bunch of old caps from the Traynor that I can use to convert it.

If I played with no dirt pedals, I would leave the amp alone or just convert it to 1986 specs because it is truly lovely. But I need it to be a better platform for lower volumes with a pedal board.

Anyway... !

[neikeel]

Got the new power cord installed and....


HELL YES!!!

VERY QUIET! Loving this amp.

Thanks for just letting me spitball on the web. Lesson learned though, definitely check the power cable. Most everyone where is using the Marshall style IEC conector, but in case you aren't, check the cable if you have 120hz buzz and the chassis stops the buzz.

so it was an earth/ground issue all the time.................

Well at least you are up and running now.

[marshallnoise]

Got the new power cord installed and....


HELL YES!!!

VERY QUIET! Loving this amp.

Thanks for just letting me spitball on the web. Lesson learned though, definitely check the power cable. Most everyone where is using the Marshall style IEC conector, but in case you aren't, check the cable if you have 120hz buzz and the chassis stops the buzz.

so it was an earth/ground issue all the time.................

Well at least you are up and running now.

Yeah, just WAY upstream. I kept focusing on the details and not the whole picture.

[neikeel]

Your mains has a dedicated ground?

[marshallnoise]

Your mains has a dedicated ground?

Yeah yeah! To be fair, it was intermittent when I tested it. It tested good because the plug end had to be pressed to get continuity. Plug it into the wall and no continuity.

[neikeel]

Your mains has a dedicated ground?

Yeah yeah! To be fair, it was intermittent when I tested it. It tested good because the plug end had to be pressed to get continuity. Plug it into the wall and no continuity.

[ivan H]

Second, channel II is unbelievably bright and channel I is VERY bassy and not clear until opened wide. I am going to convert the whole amp to 1986 specs.: !

Hi, converting to 1986 spec u'll find it similar to the "very bassy" channel. This is due to the 330uf cathode cap (tho the tone stack helps some in the 1986). Wot u can do to ur very bassy channel is change that V1 330uf cathode cap to a 10uf. This will still give a flat frequency response without the excessive farty low end. Also these amps r great with th channels jumpered, ie; plug into the hi input of either channel, then take a lead from that channels low input across to the other channels hi input. Cheers

[marshallnoise]

Second, channel II is unbelievably bright and channel I is VERY bassy and not clear until opened wide. I am going to convert the whole amp to 1986 specs.: !

Hi, converting to 1986 spec u'll find it similar to the "very bassy" channel. This is due to the 330uf cathode cap (tho the tone stack helps some in the 1986). Wot u can do to ur very bassy channel is change that V1 330uf cathode cap to a 10uf. This will still give a flat frequency response without the excessive farty low end. Also these amps r great with th channels jumpered, ie; plug into the hi input of either channel, then take a lead from that channels low input across to the other channels hi input. Cheers

That's a good idea with the 330uf cathode cap. I already ordered the PPIMV mod from Triode as well as the parts necessary to do the 1986 conversion.

I have tried doing the mixing of the two channels. I agree 100% that is the way to go if you can get enough volume to make mixing the channels a less sensitive operation. But, since I can't crank the amp for my current and steady live situation, making the normal channel more usable will help.

The one thing I noticed about the 1987 circuit is that it does not take tube screamers as well as my old 2204 used to. I realize I am going the other direction with less gain stages, but this whole thing is a giant experiment for me anyway!

[marshallnoise]

There is how it stands now. Bone stock 1986. I like it better. Way less shrill. I was able to rob many of the caps off the Traynor circuit board so bam, lots of old mustard in there. I am still jumpering the channels.

I am still looking forward to the PPIMV. I think it will do what I hope which is open up the front end a bit.

[marshallnoise]

Annnnd! I am spent.

This amp freaking rocks. PPIMV was just the touch I wanted. Allows the front end to breathe a bit.

I also pulled the EH preamp tubes in favor of a Russian Groove Tube in the PI, a JJ Medium Plate in the 2nd position and a JAN Phillips 12AX7 in the first position.

[marshallnoise]

Long time update.

I changed the cathode bypass cap back to .68uf and then changed the negative feedback resistor to 100K. I am much happier with the amp this way. I play it always jumpered and just try to find the happy medium between bright and dark.



Now, my next project...its a Bugera 1990 chassis and transformers with all fresh guts for an early 80s 2203!