12-Series Build goonies

vanhalen5150 · Post by **vanhalen5150** » Thu Mar 12, 2015 7:57 am

I was reading a post yesterday with Bruce Egnater and Roy Blankenship talking about how the old Fenders that sound really great have those 100k drifted up to about 115K.

You have to wonder if that's actually age or if its from the initial soldering that bumps them up. Blankenship has tested some that were up to 170K! Guess the amp sounded bad with those.

Goonies · Post by **Goonies** » Sun Mar 29, 2015 1:22 am

transformers arrived today. Classic tone. Still wating for marstrans . Bought in january.. to much time to ship.

Classic tone output transformer does not fit in chassi´s holes. 40-18026

http://www.classictone.net/40-18026.pdf

distance 3 1/4 inches does not fit into chassis holes. Only 2 7/8 inches fits.

my chassi is 12 series from valvestorm. Laydown PT.

thanks

Strat78 · Post by **Strat78** » Sun Mar 29, 2015 10:23 am

That sounds about right for Marstran, these things take time I guess. It's a given that you will have to drill new holes to make the OT fit, seems like no two manufacturer are the same. just make sure you are not obscuring the grommet holes with the transformer. It's all good.

Goonies · Post by **Goonies** » Sun Mar 29, 2015 3:54 pm

Strat78,

thanks man, i will do 4 new holes.

I'm very excited to hear the sound of this amp.

Goonies · Post by **Goonies** » Mon Mar 30, 2015 9:29 am

forgive my ignorance, my DPST Switch is carling 20A @125v,10A @250v.

To mount the JTM45 50W 1969 and 12xxx kits are of different values switchs?

thanks

Goonies · Post by **Goonies** » Fri Apr 03, 2015 11:27 pm

Job done!

finished the build today! but it´s 11pm late night, and i played only 2 mins on volume 5. I don´t know if every thing is fine yet. All readings are OK, my voltage is 127volts.

power sockets pin 3 is 534v, i biased to 60% 28mA, and it is 8omhs tap.

Very excited to play tomorow at full volume and a couple of pedals.

I had a very difficult time to install the strain relief bushing on power cord. I could not install. The cord is twisting and i´m afraid to disconect some solder by the move.

Anybody knows how to install ?

http://heyco.com/blog/wp-content/upload ... 060B-1.jpg

took some picture today
http://postimg.org/image/pxzn4950h/
http://postimg.org/image/76xpu3ag1/
http://postimg.org/image/vbyfbsuqp/
http://postimg.org/image/5homm0uqp/
http://postimg.org/image/6y0545xnl/

The ground scheme i try to copy larry ground mode,drilled some holes, and the only problem was the short wires from power transformers to solder on #1 point with inputs and V1 cathode.

I did not understand this on the PDF 100W kit:
"Using a sharp knife or scraper, scrape the
red insulating enamel off of each lead . failure to do
this will result in poor connections and potential damage
to your amp!" on impedance switch.

I skipped that part. Is this a problem?

thanks

Tazin · Post by **Tazin** » Sat Apr 04, 2015 3:14 pm

Goonies wrote:I did not understand this on the PDF 100W kit:
"Using a sharp knife or scraper, scrape the
red insulating enamel off of each lead . failure to do
this will result in poor connections and potential damage
to your amp!" on impedance switch.

I skipped that part. Is this a problem?

thanks

In your case it's not a problem since the OT does not appear to be a "self lead' type, rather it uses tinned copper hookup wire for the secondary leads. If the amp seems a bit noisy then you might think about shortening the arcs on the black heater wires for the preamp tube sockets. Likewise, you could try re-arranging the green wires on the first preamp tube socket (V1) so that they are kinda isolated from the other wires to reduce possible cross talk.

Goonies · Post by **Goonies** » Sun Apr 05, 2015 1:11 pm

Tazin,

thanks!!

THe sound is amazing!!!!!!!!!!!!!!!!!

My only concern is the Power transformers are too hot after 1 hour. Really hot. The sound still amazing, but i cannot touch the PT.

my voltage is 127v the transformers is 120v.

Is it normal?

http://postimg.org/image/opeq7c6cf/
http://postimg.org/image/yuifu0v8f/
http://postimg.org/image/q1wf983rz/
http://postimg.org/image/gimqfrg9r/
http://postimg.org/image/xa81yigin/
http://postimg.org/image/5ghnhbm73/
http://postimg.org/image/4na3ltmhr/
http://postimg.org/image/o6eov6l9b/

thanks

Tazin · Post by **Tazin** » Sun Apr 05, 2015 2:18 pm

If your playing the amp full tilt for an hour straight then I would expect the PT to get kinda hot but not to the point were you would get a serious burn if you touched it. The 127Vac line voltage is adding to the extra heat I'm sure. Sounds like you need either a variac or a power conditioner to keep the line voltage down at 120Vac.

rgorke · Post by **rgorke** » Thu Apr 30, 2015 3:07 pm

Yeah, variac it down to 110 or lower, depending on what you are looking for. Under 120, I would bet the PT won't be as hot.

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