Which amp to use?

[Turbo T]

Scored me a few amps....a Black car HD 300 and a Bimbo 100 bilinear.

Both are 2 pill amps.

The Black Cat has the SD1446's in it, while the Bimbo has PT9797A's in it.

Bought one on impulse and the other because I wanted an amp for not a lot of cash.

I'm guessing the Bimbo is a cleaner amp than the Black Cat?

 

[BOOTY MONSTER]

the bimbo looks to be AB biased and filtered .

 

[9C1Driver]

The Black Cat is the same as a Palomar Elite 300, class C, auto SSB delay, ok for the money but not the best choice.

If the other one is an 11m AB amplifier then that would be great. Never heard of those finals though, have to see if they even still make em.

 

[IMD262]

The Black Cat is the same as a Palomar Elite 300, class C, auto SSB delay, ok for the money but not the best choice.

If the other one is an 11m AB amplifier then that would be great. Never heard of those finals though, have to see if they even still make em.

These have not been in production for years.

 

[ExitThirteen]

The Bimbo would be your best bet. Just keep it low deadkey on AM and about 15W or so SSB input and you should be fine. The SD1446's that are in the Black Cat aren't even rated for 26-30mhz service. They won't be very efficient in that frequency range. they're a 50 Mhz device.

The PT9797's are not being made. Those are a 50w or 60W stud-mount final, if memory serves right. Stud mounted finals are quite rare. Definitely make sure to keep input low, and that Bimbo will do just fine, with many more years of service.



~Cheers~

 

[Turbo T]

The Bimbo would be your best bet. Just keep it low deadkey on AM and about 15W or so SSB input and you should be fine. The SD1446's that are in the Black Cat aren't even rated for 26-30mhz service. They won't be very efficient in that frequency range. they're a 50 Mhz device.

Thanks. I have the Uniden Pro 510 XL (that is driving the Bimbo) down to 1 watt deadkey/4-5 watt modulation.

As for the SD1446's....yeah I was reading they're actually rated for 50 MHz....makes me wonder if this amp would be better used on the 6 meter ham band?

The PT9797's are not being made. Those are a 50w or 60W stud-mount final, if memory serves right. Stud mounted finals are quite rare.

Never heard of stud mounted transistors on an amp, please clarify?

 

[ExitThirteen]

Stud-mount Transistors were real common when those amps were made... back in the 70's. These were designed to bolt thru the heatsink to dissipate heat. Have a look at the Bimbo amp on the finned side, and you'll see two studs thru the heatsink.

In the late 70's/early 80's the manufacturers found out that increasing the contact area of the transistor to the heatsink allowed better heat dissipation. Hence the flange-mount transistors you see in the Black Cat. There's more surface area that is in contect with the heatsink, therefore they tend to have better heat dissipation. More area = better thermal transfer. Hope this helps ya.


~Cheers~

 

[Turbo T]

Thanks, this does help, and yes I do believe I saw 2 small screws that protruded thru the heat sink on the Bimbo.

I did notice on the Black Cat there's 2 holes in the heat sink, but no screws thru/in them.

Also wondering if the Black cat would be a better amp on 6 meter since the pills are for 54 MHz?

 

[AudioShockwav]

As 13 said, the Stud mounts ( case 145A-09/10 and 244-04) are getting rare, like the MRF 455A. (included a PDF file that shows the MRF 455 and MRF 455A case styles )

Here is a link to RFParts that shows most of the different style cases.
Transistor Case Styles at RF Parts Company
The SD 1446 although designed as a VHF transistor works fairly well at 28/30 MHz.
There are lots of them used in 10/11 meter amps.
There are transistors that are made to work in the VHF region the will play at HF frequencies, like the MRF 497 that is a 50 MHz transistor.
It can be used to replace the MRF 477 ( watch pin out on leads) that is a HF transistor.
Although the transistor would be fine at 6 meters, It will not be a plug and play amp for 6.

73
Jeff

 

[TonyV225]

As for running that Black Cat / Palomar on 6 meters there would have to be some mods done and Im not sure it would even be worth doing.

 

[Turbo T]

Thanks I probably won't bother modding it.

I take it the Black cat will produce more watts and be heard farther than the Bimbo but the Bimbo will be a cleaner sounding amp?

 

[BOOTY MONSTER]

SD1446 pdf, SD1446 description, SD1446 datasheets, SD1446 view ::: ALLDATASHEET :::

looking at the power input/output graph and the impedance graph they seem to perform just fine from slightly below 30MHz to over 80MHz .

 

[psycho]

Thanks I probably won't bother modding it.

I take it the Black cat will produce more watts and be heard farther than the Bimbo but the Bimbo will be a cleaner sounding amp?

I thought you knew better than to think one 2 pill will be heard further than another 2 pill.
I had my share of Bimbos and they were all fun to play with a few times but they get boring pretty fast.

 

[Turbo T]

I thought you knew better than to think one 2 pill will be heard further than another 2 pill.

If I would have thought something, then I would not have asked now would have I?

 

[psycho]

If I would have thought something, then I would not have asked now would have I?

Good answer!