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Tubetwang
July 18th 03, 05:01 PM
built a passive pre-amp for my rebuilt ST-70 using a step attenuator.
Would an active pre-amp work better with the Dynaco?
Have the Foreplay in mind...
Thanks,
Twang

Jon Yaeger
July 19th 03, 07:08 AM
In my experience, things always go better with a little Foreplay.

;-)

> From: (Tubetwang)
> Organization: http://groups.google.com/
> Newsgroups: rec.audio.tubes
> Date: 18 Jul 2003 09:01:53 -0700
> Subject: pre-amp for Dyna ST-70
>
> built a passive pre-amp for my rebuilt ST-70 using a step attenuator.
> Would an active pre-amp work better with the Dynaco?
> Have the Foreplay in mind...
> Thanks,
> Twang

Mikkel C. Simonsen
July 19th 03, 04:27 PM
Tubetwang wrote:
>
> built a passive pre-amp for my rebuilt ST-70 using a step attenuator.
> Would an active pre-amp work better with the Dynaco?

Can you play load enough with all your signal sources? If that's the
case you don't need a preamp, if you can't then you do need a preamp.

If you want a preamp as an "effect unit" to change the sound, that's a
different matter...

Best regards,

Mikkel C. Simonsen

Ronald
July 19th 03, 06:51 PM
Hi ,

> If you want a preamp as an "effect unit" to change the sound, that's a
> different matter...

It might be better tu upgrade the ST-70 then .....
Or even rebuild it just using the iron and a different topology ......
2A3 - PP might be an option ........

Ronald .

Ronald
July 19th 03, 07:28 PM
Hi ,

> > 2A3 - PP might be an option ........
>
> Why not 6B4G PP - they will fit in the original sockets. Ned Carlson has
> made such an amp using the Sovtek 6B4G tubes as far as I remember...

OK , you're right , but the 2A3 might be better known .....
It's up to Tubetwang now to react ......
So we can help him better .

Regards ,

Ronald .

Mikkel C. Simonsen
July 19th 03, 08:15 PM
Ronald wrote:
>
> Hi ,
>
> > If you want a preamp as an "effect unit" to change the sound, that's a
> > different matter...
>
> It might be better tu upgrade the ST-70 then .....
> Or even rebuild it just using the iron and a different topology ......
> 2A3 - PP might be an option ........

Why not 6B4G PP - they will fit in the original sockets. Ned Carlson has
made such an amp using the Sovtek 6B4G tubes as far as I remember...

Best regards,

Mikkel C. Simonsen

Tubetwang
July 19th 03, 10:40 PM
"Ronald" > wrote in message >...
> Hi ,
>
> > > 2A3 - PP might be an option ........
> >
> > Why not 6B4G PP - they will fit in the original sockets. Ned Carlson has
> > made such an amp using the Sovtek 6B4G tubes as far as I remember...
>
> OK , you're right , but the 2A3 might be better known .....
> It's up to Tubetwang now to react ......
> So we can help him better .
>
> Regards ,
>
> Ronald .


Thanks guys , you have answered well!

This ST70 has been rebuild with Ned's board and power supply and i am
very please with the sound of it with the Jensen Copper caps.

I had rebuild two other amps previously, namely Dyna (SCA35)and
Heatkit AA-151 using a stepped attenuator on each.
The soud was "blooming " quicker on those (1/4 turn).

I have to turn the volume 15 minutes more on the ST70 to get the same
sound.
So i was wondering...

It's working great so i'll enjoy it...
Thanks again!
Twang

Ronald
July 19th 03, 11:54 PM
I don't know the ST70 that good and don't know Ned's board at all ....
But if not already you can get some extra gain if the cathode resistors
are not by-passed yet ......
On the other hand this might add some colouring of the sound ......

"Tubetwang" > schreef in bericht
om...
> "Ronald" > wrote in message
>...
> > Hi ,
> >
> > > > 2A3 - PP might be an option ........
> > >
> > > Why not 6B4G PP - they will fit in the original sockets. Ned Carlson
has
> > > made such an amp using the Sovtek 6B4G tubes as far as I remember...
> >
> > OK , you're right , but the 2A3 might be better known .....
> > It's up to Tubetwang now to react ......
> > So we can help him better .
> >
> > Regards ,
> >
> > Ronald .
>
>
> Thanks guys , you have answered well!
>
> This ST70 has been rebuild with Ned's board and power supply and i am
> very please with the sound of it with the Jensen Copper caps.
>
> I had rebuild two other amps previously, namely Dyna (SCA35)and
> Heatkit AA-151 using a stepped attenuator on each.
> The soud was "blooming " quicker on those (1/4 turn).
>
> I have to turn the volume 15 minutes more on the ST70 to get the same
> sound.
> So i was wondering...
>
> It's working great so i'll enjoy it...
> Thanks again!
> Twang

Jon Yaeger
July 20th 03, 06:04 AM
I've rebuilt a number for ST-70s using different pre-packaged mods. With
all due respects to Ned, the Welbourne Labs mod is the best I've heard so
far. I'm in the process of putting together my second Welbourne ST-70 (the
first was sold to a fellow who wanted it so bad he was willing to pay $700).

I've been working on a few tube pre-amps. The Van Alstine PAS mod was
frankly a disappointment. I've been looking at Patrick Turner's April 200
circuit and it looks most intriguing . . .

- Jon

> From: "Ronald" >
> Organization: @Home Benelux
> Newsgroups: rec.audio.tubes
> Date: Sat, 19 Jul 2003 20:28:19 +0200
> Subject: Re: pre-amp for Dyna ST-70
>
> Hi ,
>
>>> 2A3 - PP might be an option ........
>>
>> Why not 6B4G PP - they will fit in the original sockets. Ned Carlson has
>> made such an amp using the Sovtek 6B4G tubes as far as I remember...
>
> OK , you're right , but the 2A3 might be better known .....
> It's up to Tubetwang now to react ......
> So we can help him better .
>
> Regards ,
>
> Ronald .
>
>