2rd Gen 100W hybrid completed

[ToneMerc]

Here's the board mocked up with the same values as the one called #40.

TM

[David Root]

Excellent period parts detail! You must have quite a stock! You will love it. I did a 50W very similar last year.

Just noticed this, maybe it's the lighting in the pic but the TS slope resistor looks like 100R, not 100K.

[talbany]

Looks great so far.. also don't forget the 500pf ceramic across the 220k OD entrance resistor or it may oscillate..

Good Luck with the build

Tony

[ToneMerc]

Excellent period parts detail! You must have quite a stock! You will love it. I did a 50W very similar last year.

Just noticed this, maybe it's the lighting in the pic but the TS slope resistor looks like 100R, not 100K.

Yeah, I have a lil bit, but I'm now either out or low on the common critical values.

Thanks David good catch, it was a 100 ohm. It doesn't do any good to measure all the values if I don't install the correct value in the correct location.

The 180K to ground should be a .5W Piher, but I can't put my hands on either of the two that I thought I had. Thus, I had to use a Beyschlag instead. I'm not going to use that 1M into the relay and will most likely install a 330K with a 1M pot in series with it. Also, since I'm going have Pres control I'm going to sub in a value other than that 100 ohm tail in the GNFB circuit.

TM

[ToneMerc]

Looks great so far.. also don't forget the 500pf ceramic across the 220k OD entrance resistor or it may oscillate..

Good Luck with the build

Tony

Thanks Tony, yeah I'm debating on ceramic or mica.

TM

[ToneMerc]

Remaining boards & big iron

Twin PT: 365V @ 535mA, 6.3V @ 500mA, 6.3V @ 8.5A
Choke: 5H-250mA
OT: 1.9K, 4-8-16, 150W

TM

[groovtubin]

Excellent period parts detail! You must have quite a stock! You will love it. I did a 50W very similar last year.

Just noticed this, maybe it's the lighting in the pic but the TS slope resistor looks like 100R, not 100K.

I know for SURE that that value WAS used in a particular dumble, reason? It was given to me by a guy on w coast with a DUNBLE ( cloned from real thing) that was INSANELY AWESOME, nothing here at this site has ever touched it, and i can say that emphatically! I`ve heard it! It TOTALLY nailed the RF thing, i mean NAILED it..FAT, NO ugly harmonics period....sounded like a saxaphone w/KAHUNAS! Vocal quality and sustain out the yin yang..

Omegaamps

[marcos]

. Also, since I'm going have Pres control I'm going to sub in a value other than that 100 ohm tail in the GNFB circuit.

TM

Hi ToneMerc,

you don´t have to change the 100R tail. The presence mod
recommended to me by HAD himself was adding a 500R pot
in series with the presence cap. A 1 K pot also works great here.
BTW HAD told me to try different values for the cap,
from 470 nF up to 4.7 µF AFAIR.At the time I was surprised by the large range he recommended, my current favourite is 2.2 µF.
The 1 µF is a good value for the Accent switch IMHO,
but the 2.2 µF (or greater) provides more range for a real
presence control.Looking forward to your build

Marcos

[Structo]

The tail or the tone stack slope resistor?

[marcos]

Tom,
I was referring to the Fender-style 820R/100R GNFB loop used in the
power amp section of the 70s ODS amps.On some of amps (such as Rick Vito´s ) HAD replaced the Accent switch with a presence pot, so I wrote to him
asking about this mod.This was way back in 1986.

Marcos

[ToneMerc]

. Also, since I'm going have Pres control I'm going to sub in a value other than that 100 ohm tail in the GNFB circuit.

TM

Hi ToneMerc,

you don´t have to change the 100R tail. The presence mod
recommended to me by HAD himself was adding a 500R pot
in series with the presence cap. A 1 K pot also works great here.
BTW HAD told me to try different values for the cap,
from 470 nF up to 4.7 µF AFAIR.At the time I was surprised by the large range he recommended, my current favourite is 2.2 µF.
The 1 µF is a good value for the Accent switch IMHO,
but the 2.2 µF (or greater) provides more range for a real
presence control.Looking forward to your build

Marcos

Marcos, I'm going to use either a 500 or 1K pot and a 2.2uF. A couple of years ago I picked Brandon's brain about these amps, he had recommended a 1K pot as well.

Thank you much

Mike

[ToneMerc]

Chassis work, phase 1.

TM

[David Root]

Tonemerc, what make and model is your PT and OT?

[ToneMerc]

Tonemerc, what make and model is your PT and OT?

OT: Hammond 1650TA
PT: Heyboer Twin style that I had custom wound.

Mike

[ToneMerc]

Started on perimeter wiring.