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Driver Transistors

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Anonymous
May 29, 2004 5:57:26 AM

Archived from groups: rec.audio.tech (More info?)

Hi Group,

Thanks to those in the group who have been kind enough to help me with my SS
amp learning curve.

I have finished repairing both amps (Fender Stage Lead - guitar amp).

I have an interesting conclusions about driver transistors.

Bob (burbeck) informed me the TIP29/30 series could be replaced using the
TIP 41/42 series as drivers for the MJ15003.

Using the TIP41/42C drivers gave the amp a bigger sound and the nice "honk"
the owner was looking for,, think Fender Twin Reverb ala 1971 or so.

Being a Toob guy, it seems there are definite parallels between the two
domains in terms of the devices.

I know from firsthand experience building high power toob amps (6 6550A/s to
produce 560 watts rms) that you need to really drive the grids hard with a
solid current source (AB2) to really get them to thump.

I am guessing using the more robust TIP41/42 drives the outputs harder, or
am I way off track here?

I know i need to study up here,, but what would the the RDH (Radiotron
Designer Handbook) for solid state devices?

Thanks again for the help,,,

Vin Collins

More about : driver transistors

Anonymous
May 29, 2004 8:50:55 AM

Archived from groups: rec.audio.tech (More info?)

I'm no engineer but having said that, I would think the drive of the 41/42
combination, just as the 29/30, are determined by circuit values - resistors
and capacitors mainly. The higher numbered transistors can handle more
current / voltage, OK that's fine and all, but I'm pretty sure differences
you hear are for some other reason, and possibly even a psychological effect
(it happens to all of us).

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"JVC" <spambegone@spam.com> wrote in message
news:a6Stc.1170$LS6.388@nwrdny01.gnilink.net...
> Hi Group,
>
> Thanks to those in the group who have been kind enough to help me with my
SS
> amp learning curve.
>
> I have finished repairing both amps (Fender Stage Lead - guitar amp).
>
> I have an interesting conclusions about driver transistors.
>
> Bob (burbeck) informed me the TIP29/30 series could be replaced using the
> TIP 41/42 series as drivers for the MJ15003.
>
> Using the TIP41/42C drivers gave the amp a bigger sound and the nice
"honk"
> the owner was looking for,, think Fender Twin Reverb ala 1971 or so.
>
> Being a Toob guy, it seems there are definite parallels between the two
> domains in terms of the devices.
>
> I know from firsthand experience building high power toob amps (6 6550A/s
to
> produce 560 watts rms) that you need to really drive the grids hard with a
> solid current source (AB2) to really get them to thump.
>
> I am guessing using the more robust TIP41/42 drives the outputs harder, or
> am I way off track here?
>
> I know i need to study up here,, but what would the the RDH (Radiotron
> Designer Handbook) for solid state devices?
>
> Thanks again for the help,,,
>
> Vin Collins
>
>
Anonymous
May 29, 2004 10:47:48 AM

Archived from groups: rec.audio.tech (More info?)

JVC wrote:
> Hi Group,
>
> Thanks to those in the group who have been kind enough to help me
> with my SS amp learning curve.
>
> I have finished repairing both amps (Fender Stage Lead - guitar amp).
>
> I have an interesting conclusions about driver transistors.
>
> Bob (burbeck) informed me the TIP29/30 series could be replaced using
> the TIP 41/42 series as drivers for the MJ15003.

> Using the TIP41/42C drivers gave the amp a bigger sound and the nice
> "honk" the owner was looking for,, think Fender Twin Reverb ala 1971
> or so.

Naah, you're just happy to have the amp back working again. Last time you
"heard" it, it was broken. Working right always sounds better than broken.

> Being a Toob guy, it seems there are definite parallels between the
> two domains in terms of the devices.

A lot of what the "Toob guys" talk about is IME imaginary. With tubes
there's a bigger chance of this happening because tubed equipment tends to
be far more marginal, in terms of exposing the performance of the unit to
the variable properties of the active devices. But IME the situation is
still often vastly overstated. Toob guys don't do DBTs, as a rule.

SS gear is designed with the idea that the active components are going to be
high variable. Therefore, the circuit's performance tends to be more
independent of the properties of individual devices.

> I know from firsthand experience building high power toob amps (6
> 6550A/s to produce 560 watts rms) that you need to really drive the
> grids hard with a solid current source (AB2) to really get them to
> thump.

Now, you're talking something other than hifi. You're talking about power
amps as EFX boxes.

> I am guessing using the more robust TIP41/42 drives the outputs
> harder, or am I way off track here?

More likely: "constructor's ear".

> I know I need to study up here,, but what would the the RDH (Radiotron
> Designer Handbook) for solid state devices?

There was such a thing as the RCA Solid State Devices handbook, and you can
probably find some old copies.

TIP stands for "Texas Instruments Plastic". You'll find spec sheets for many
solid state devices in old TI and Motorola solid state device data books.
The MJE series devices were originated by Motorola. I believe that TI sold
off their entire discrete devices product line to ON semiconductor, or was
that Motorola? So many mergers, so many sell-outs!

In the case of the TIP line of devices, searching google brought up at least
a half-dozen data sheets.

If you want learn about modern circuit design, here's an intersting list:

http://www.amazon.com/exec/obidos/tg/listmania/list-bro...
Related resources
Anonymous
May 31, 2004 6:31:21 PM

Archived from groups: rec.audio.tech (More info?)

On Sat, 29 May 2004 01:57:26 GMT, "JVC" <spambegone@spam.com> wrote:

>Hi Group,
>
>Thanks to those in the group who have been kind enough to help me with my SS
>amp learning curve.
>
>I have finished repairing both amps (Fender Stage Lead - guitar amp).
>
>I have an interesting conclusions about driver transistors.
>
>Bob (burbeck) informed me the TIP29/30 series could be replaced using the
>TIP 41/42 series as drivers for the MJ15003.
>
>Using the TIP41/42C drivers gave the amp a bigger sound and the nice "honk"
>the owner was looking for,, think Fender Twin Reverb ala 1971 or so.
>
>Being a Toob guy, it seems there are definite parallels between the two
>domains in terms of the devices.
>
>I know from firsthand experience building high power toob amps (6 6550A/s to
>produce 560 watts rms) that you need to really drive the grids hard with a
>solid current source (AB2) to really get them to thump.
>
>I am guessing using the more robust TIP41/42 drives the outputs harder, or
>am I way off track here?
>
>I know i need to study up here,, but what would the the RDH (Radiotron
>Designer Handbook) for solid state devices?
>
>Thanks again for the help,,,
>
>Vin Collins
>

hi Vin,
i dont know about you being "way off track" i agree with Mark and
Arnie on all of their points, however the changing the output devices
and or the drivers does seem to give these amps a "different zing",
the only explanation i can offer is that the modern variation of the
devicies seem to have more gain i.e more at the top end of there spec.
this may have a bearing on the different "zing" that seems to happen.
or i may have been foolin myself all these years. with the
satisfaction of the thing coming back to life.
regards
bob
Anonymous
May 31, 2004 8:44:13 PM

Archived from groups: rec.audio.tech (More info?)

Hi Arny, your hotpop account reports account closed due to inactivity
.... ???


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
May 31, 2004 8:44:14 PM

Archived from groups: rec.audio.tech (More info?)

Peter Larsen wrote:
> Hi Arny, your hotpop account reports account closed due to inactivity
> ... ???

It was a repeated victim of massive spam attacks. I monitor a like-named
account at Comcast. So, my *real* email address is arnyk at comcast dot net.
Anonymous
June 1, 2004 2:59:59 AM

Archived from groups: rec.audio.tech (More info?)

Hi Bob,

Yeah, I think it is a slight audible difference with the TIP 40 series,, I
had two identical amps,, and listened to both one with 29/30's and the other
with the 40 series,,, then I put 40 series in and it seemed to have a little
more sheen or sparkle..probably a freq response thing,,,,

thanks again for all your help,, I am starting to dig this transistor
stuff!!

Vin



"burbeck" <crooksie@bigfoot.com> wrote in message
news:mocmb0p8mg3a5c606ar1f8ns158jjps1vf@4ax.com...
> On Sat, 29 May 2004 01:57:26 GMT, "JVC" <spambegone@spam.com> wrote:
>
> >Hi Group,
> >
> >Thanks to those in the group who have been kind enough to help me with my
SS
> >amp learning curve.
> >
> >I have finished repairing both amps (Fender Stage Lead - guitar amp).
> >
> >I have an interesting conclusions about driver transistors.
> >
> >Bob (burbeck) informed me the TIP29/30 series could be replaced using the
> >TIP 41/42 series as drivers for the MJ15003.
> >
> >Using the TIP41/42C drivers gave the amp a bigger sound and the nice
"honk"
> >the owner was looking for,, think Fender Twin Reverb ala 1971 or so.
> >
> >Being a Toob guy, it seems there are definite parallels between the two
> >domains in terms of the devices.
> >
> >I know from firsthand experience building high power toob amps (6 6550A/s
to
> >produce 560 watts rms) that you need to really drive the grids hard with
a
> >solid current source (AB2) to really get them to thump.
> >
> >I am guessing using the more robust TIP41/42 drives the outputs harder,
or
> >am I way off track here?
> >
> >I know i need to study up here,, but what would the the RDH (Radiotron
> >Designer Handbook) for solid state devices?
> >
> >Thanks again for the help,,,
> >
> >Vin Collins
> >
>
> hi Vin,
> i dont know about you being "way off track" i agree with Mark and
> Arnie on all of their points, however the changing the output devices
> and or the drivers does seem to give these amps a "different zing",
> the only explanation i can offer is that the modern variation of the
> devicies seem to have more gain i.e more at the top end of there spec.
> this may have a bearing on the different "zing" that seems to happen.
> or i may have been foolin myself all these years. with the
> satisfaction of the thing coming back to life.
> regards
> bob
>
!