I recently purchased one of these little amps and was wondering what I
should do in terms of mods if any. I am not at all familiar with tubes so I
really can't say if I am getting good sound right now or not. Any help would
be greatly appreciated.

Phil

Phil Budgell wrote:

I recently purchased one of these little amps and was wondering what I
should do in terms of mods if any. I am not at all familiar with tubes so I
really can't say if I am getting good sound right now or not. Any help would
be greatly appreciated.

Phil

Phil,

the general consensus on these little integrated amps goes something like
this:

- good output iron
- mundane and average circuit
- average to poor grade parts
- average sound

The general thought is that you can use the iron (power and output) to
make a decent low power tube amp, or you can mod the existing amp by
more or less gutting it, and removing non essential circuit parts (like the
tone controls, any rocker switch that the signal goes through, improving
the wiring, and upgrading the power supply filtering, using film caps
and metal film or similar higher grade resistors.

What exactly to do depends upon your experience and skill level.

Based upon your question, I assume you are a neophyte on tube gear,
so I suggest doing the minumum to start; change the caps out for
better caps; and/or try switching it to triode mode.

--This assumes you can solder, and that you will not electrocute
or shock yourself putting your hands inside the unit. There are dangerous
and DEADLY voltages present in that unit. --

If you are unsure, read a whole lot before attempting this sort of work.

There a multiple web publications, and print publications on tubes, tube amps
and the hobby. Find a local person who knows audio, tubes or even an experienced
ham radio operator (one who builds stuff...) for support.

Repeat: THERE ARE DEADLY VOLTAGES PRESENT IN TUBE GEAR.

Regards,

_-_-bear


--
_-_- BEAR Labs
- Custom Audio Equipment, Cables, Mods, Repairs -
http://www.bearlabs.com

On Sat, 17 Jan 2004 17:31:38 +0000, Phil Budgell wrote:

I recently purchased one of these little amps and was wondering what I
should do in terms of mods if any. I am not at all familiar with tubes so
I really can't say if I am getting good sound right now or not. Any help
would be greatly appreciated.

Phil

A couple of things you can do with the Dynaco SCA-35 that are fairly
simple. First, replace the capactitors with better quality ones. Another
common mod is to wire around the tone circuit to take it out of the loop.
The tone controls on the SCA-35 are one of its weaker points.

Phil Budgell wrote:

...so I really can't say if I am getting good sound right now or not.

How will you know if it sounds better after you modify it if you can't
tell now whether it sounds good or not?

--
Len Moskowitz PDAudio, Binaural Mics, Cables, DPA, M-Audio
Core Sound http://www.stealthmicrophones.com
Teaneck, New Jersey USA http://www.core-sound.com
Tel: 201-801-0812, FAX: 201-801-0912

Phil Budgell wrote:

I recently purchased one of these little amps and was wondering what I
should do in terms of mods if any. I am not at all familiar with tubes so I
really can't say if I am getting good sound right now or not. Any help would
be greatly appreciated.

Nice small amp within its capabilities, an actual 15 or so watts per
channel. The EL84/6BQ5/7189 output tube is good-sounding but they run
hot. See that the ones you have are up to snuff, and clean up the
switches and controls with Cramolin or DeOxit-5.

Amp could benefit from beefing up power supply capacitance, and higher
quality film capacitors for interstage coupling.

The preamp tubes need to be checked too. The 7199 drivers are now being
made in Russia again after years of unavailability, so if one is bad you
don't have to rewire the socket for a 6AN8 or 6GH8; but they don't go
bad very often. If yours are working and they don't look milky or
cloudy they are likely OK. If they are weak or bad, Antique Electronics
has them.

-GP

They were rather doggy. Bear offers good advise here, but I would add
that it is best to just move-on and let someone else fool with it. You
can get much better sounding tube amps at relatively low prices from
Antique Sound Lab and Jolida to name a couple. Thoroughly modern and
clean sounding units. They also come with warranty and as a nice side,
you won't kill yourself trying to make a silk purse from a sow's ear.
- Bill
www.uptownaudio.com
Roanoke VA
(540) 343-1250

"Phil Budgell" wrote in message
...
I recently purchased one of these little amps and was wondering what
I
should do in terms of mods if any. I am not at all familiar with
tubes so I
really can't say if I am getting good sound right now or not. Any
help would
be greatly appreciated.

Phil

If you want an expert to upgrade your amp, try the Dynaco Doctor at
http://www.curcioaudio.com/dynadr_3.htm. He just upgraded an ST-35 amp for
me, and it sounds great. Both power supply and passive parts were upgraded.
Joe Curcio knows what he's doing.

Vade

"Phil Budgell" wrote in message
...
I recently purchased one of these little amps and was wondering what I
should do in terms of mods if any. I am not at all familiar with tubes so
I
really can't say if I am getting good sound right now or not. Any help
would
be greatly appreciated.

Phil