So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that are
fairly efficient but still could use a bit of power so most of the kits out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.

Get the Hammond catalogue or look at their website. Choose an output valve,
then SE or push pull. then search for schematics using that. search on
www.audioasylum.com for the valve of your choice + schematic, and look on some
tube websites. I have loads of links on my site www.artsandmedia.com

any difficulties, buy Morgan Jones "Valve Amplifiers"

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Hi:

Triode Electronics sells reproduction ST70 OPTs and PTs by Magnequest and
their own ST70 upgrade driver board. Curcio sells another version of an
ST70 upgrade board as well as a nearly exact reproduction of the original
ST70 driver board. Boards can be purchased with or w/o parts. All you'll
need is a suitable chassis and tubes for what amounts to a modern day ST70
out of all new parts. Bottom line: It can be done. However, it will not
be inexpensive.

--
Steve

On the cheap:

It's easy to find a beat up Sansui 1000a for under $100 which will get you a
massive power supply transformer and two excellent OPTs. Remove and repaint
the transformers to look like new. (Please don't butcher a restorable
1000A, if you can avoid it. The FM section is noteworthy and that receiver
is a "keeper").

The Sansui is built with 7591s, but if you are just building an amplifier
with the trannies then you can use EL34s instead (you'll need to commandeer
one of the secondary taps formerly used to drive incandescent bulbs for the
increased filament current requirements of the EL34s).

The Sansui XMFR uses a voltage doubling scheme which gives a B+ that is more
suited for EL34s vs. 7591s, IMHO.

Some people claim the Sansui OPTs outperform the OEM Dynas.

Find a suitable chassis (gee, I wonder where you could get one?)

Buy a driver circuit board from Welbourne or Triode. I think they also have
bias PCBs too - helpful, but not absolutely necessary.

Spend lots of time with some tools and you'll have something nice.

I placed a photo of one I'm building on my website at www.yaegeraudio.com.

Tonight I finished drilling the chassis. I'm designing it to incorporate
features not found in the stock Dyna ST-70:

1. Hum balance pots;
2. Individual bias adjustment for each output tube;
3. Numerical LED display of bias voltage;
4. Headphone jack;
5. Triode / Pentode mode switch;
6. Multiple mode output binding posts
7. Illuminated On/Off switch

I hope to have a few more photos of the finished project as well as a
schematic (time permitting, although time doesn't permit!)

Another favorite is to snag an Eico ST-70. They cost a lot less than the
Dyna and sound marvellous once you correct some of their design shortcomings
and flaws. The Eico has a phono preamp and a tone control section that could
be rewired into a line amp. The chassis and front panel with plastic knobs
looks pretty cheesy and could benefit from a makeover.

Good luck!

- Jon



From: "Steve O'Neill"
Organization: AT&T Worldnet
Reply-To: "Steve O'Neill"
Newsgroups: rec.audio.tubes
Date: Mon, 26 Jan 2004 00:55:38 GMT
Subject: ST-70 from new parts?

Hi:

Triode Electronics sells reproduction ST70 OPTs and PTs by Magnequest and
their own ST70 upgrade driver board. Curcio sells another version of an
ST70 upgrade board as well as a nearly exact reproduction of the original
ST70 driver board. Boards can be purchased with or w/o parts. All you'll
need is a suitable chassis and tubes for what amounts to a modern day ST70
out of all new parts. Bottom line: It can be done. However, it will not
be inexpensive.

--
Steve

There's a guy or there was on Ebay a while back that was selling complete
kits..around the $700 mark.
They were original transformers(most likely used) and all new parts.
Sometimes you can find the transformers for around $150.
Dan
"Bryan McGivney" wrote in message
...
So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying
before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction
and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits
to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that
are
fairly efficient but still could use a bit of power so most of the kits
out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't
hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.

You could build an ST-70 clone amp from available new parts. Magnaquest
sells replacement power and output transformers for the ST-70. The
schematic and detailed construction info is available free from
www.triodeelectronics.com Ned also sells the Magnaquest transformers. The
choke is available from Hammond (I believe the part number is 156R). You
can buy replacement boards for the original input circuit or you can buy
versions of the board which use different tubes than the original 7199 and
supposedly offer better sonics. The bottom line is that if you want to
build an ST-70 from scratch, all of the parts are available. Keep in mind
that the cost will exceed the cost of buying an old ST-70 and rebuilding it.
However, you will have a new amp will all brand new parts and the fun of
building something from scratch vice rebuilding an existing amp. There is
also someone on Ebay who is selling a complete ST-70 kit (old transformers
and chassis with new parts elsewhere) for around $800.00. Keep in mind that
$800.00 will buy you more modern used tube amps that would blow away the
ST-70.
Mark
"Bryan McGivney" wrote in message
...
So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying
before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction
and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits
to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that
are
fairly efficient but still could use a bit of power so most of the kits
out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't
hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.

although others might suggest using new transformers, I'll suggest to
find a pair of ST70 output transformer fromo eBay, for power transformer
and choke you can use new production. Also, if you make them monoblocks,
you'll achieve better sound and more space for future mod.

Chenchen

Bryan McGivney wrote:

So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that are
fairly efficient but still could use a bit of power so most of the kits out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.

"Bryan McGivney" wrote in message ...
So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that are
fairly efficient but still could use a bit of power so most of the kits out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.


I recall reading about a "new" version of the ST-70,but I'm not sure
who made it.I don't think it was available as a kit.

There are new "replacment" transformers,and chokes available,check out
www.triodeelectronics.com for some of them.I also seem to recall
someone that had a new chassis for sale.It was slightly different
layout than the original,but very close.Pick one of the many
replacment boards available,and you could probably build a ST-70
semi-clone from scratch! I've no idea what the cost would be
however,might be cheaper to just get one on Ebay.

Soundvalves of Ohio bought all of the Hafler / Dynaco NOS inventory and used
to offer a kit. Their old website is gone and the phone number isn't
working, but they can still be found on e-bay as Soundvalves. BTW, they
were a great source of hardware & other odds and ends for rebuilding ST-70s
and indeed the whole product line.

Apparently they still have stuff to sell. For example, here's one of their
recent (closed) auctions:

http://cgi.ebay.com/ws/eBayISAPI.dll...tegory=50 593
&sspagename=STRK%3AMEBWA%3AIT&rd=1

- Jon


From: (Nothing40)
Organization: http://groups.google.com
Newsgroups: rec.audio.tubes
Date: 26 Jan 2004 00:28:08 -0800
Subject: ST-70 from new parts?

"Bryan McGivney" wrote in message
...
So I was asking a bit ago about amp kit recommendations. After looking
around I think my favorite is the diytube.com. But like I was saying before
if I am looking at building something that is not a complete kit I would
just need something that is very well documented about the construction and
where to get parts. I see a lot of mod boards for the ST-70 or whole kits to
modify one. I am wondering how hard it would be to get the rest of the amp
and build one out of all new parts. Or does someone still put together a
whole kit for one? One of the reasons I ask is that I have speakers that are
fairly efficient but still could use a bit of power so most of the kits out
there seem like they will be a tad on the under powered side. The
diytube.com board and amp might be just enough but it certainly doesn't hurt
to have a bit more. So can it be done? Anybody got some leads for me?

TIA,
Bryan
Durham, Oregon.


I recall reading about a "new" version of the ST-70,but I'm not sure
who made it.I don't think it was available as a kit.

There are new "replacment" transformers,and chokes available,check out
www.triodeelectronics.com for some of them.I also seem to recall
someone that had a new chassis for sale.It was slightly different
layout than the original,but very close.Pick one of the many
replacment boards available,and you could probably build a ST-70
semi-clone from scratch! I've no idea what the cost would be
however,might be cheaper to just get one on Ebay.

"Mark Pearson" wrote in message
. ..
You could build an ST-70 clone amp from available new parts. Magnaquest
sells replacement power and output transformers for the ST-70. The
schematic and detailed construction info is available free from
www.triodeelectronics.com Ned also sells the Magnaquest transformers.
The
choke is available from Hammond (I believe the part number is 156R). You
can buy replacement boards for the original input circuit or you can buy
versions of the board which use different tubes than the original 7199 and
supposedly offer better sonics. The bottom line is that if you want to
build an ST-70 from scratch, all of the parts are available. Keep in mind
that the cost will exceed the cost of buying an old ST-70 and rebuilding
it.
However, you will have a new amp will all brand new parts and the fun of
building something from scratch vice rebuilding an existing amp. There is
also someone on Ebay who is selling a complete ST-70 kit (old transformers
and chassis with new parts elsewhere) for around $800.00. Keep in mind
that
$800.00 will buy you more modern used tube amps that would blow away the
ST-70.
Mark

Mark,
Can you direct me to where I can purchase a more modern tube amp that will
"blow away the ST-70 for $800? Thank you.
Cordially,
west

West,
Check on Audiogon under tube amps. An Audio Research D-76 will blow the
ST-70 so far in the weeds you would need a search party to find it. They
can be had for less than $800.00 plus they put out twice the power. You can
also find used Quicksilver Audio monoblock amps that offer all the
advantages of monoblocks for around this price and they too will outperform
the ST-70 and put out more power as well. A Conrad Johnson MV-45 went for
under $500.00 the other day.

Somehow there is a mystique that has surrounded the ST-70 like it some type
of holy grail for tube amps. It's not. It is a mediocre tube amp that does
not come close to living up to its hype. Back in the days when you could
buy one for under $200.00 with good tubes, it was a good way to get into a
tube amp on the cheap when that was all you could afford. The midrange was
and is good. Frequency extremes were lacking. Anybody who thinks the ST-70
is sonically in the same league as an ARC D-76 has a serious hearing problem
or a low-resolution system. You give me $800.00, and I can get you a far
better tube amp than an ST-70. The main reason ST-70s remain popular is
they are like McDonalds hamburgers, they sold 2 gabillion of them so
everybody and their brother has mods for them.
Mark
"west" wrote in message
...
"Mark Pearson" wrote in message
. ..
You could build an ST-70 clone amp from available new parts. Magnaquest
sells replacement power and output transformers for the ST-70. The
schematic and detailed construction info is available free from
www.triodeelectronics.com Ned also sells the Magnaquest transformers.
The
choke is available from Hammond (I believe the part number is 156R).
You
can buy replacement boards for the original input circuit or you can buy
versions of the board which use different tubes than the original 7199
and
supposedly offer better sonics. The bottom line is that if you want to
build an ST-70 from scratch, all of the parts are available. Keep in
mind
that the cost will exceed the cost of buying an old ST-70 and rebuilding
it.
However, you will have a new amp will all brand new parts and the fun of
building something from scratch vice rebuilding an existing amp. There
is
also someone on Ebay who is selling a complete ST-70 kit (old
transformers
and chassis with new parts elsewhere) for around $800.00. Keep in mind
that
$800.00 will buy you more modern used tube amps that would blow away the
ST-70.
Mark

Mark,
Can you direct me to where I can purchase a more modern tube amp that will
"blow away the ST-70 for $800? Thank you.
Cordially,
west

Mark,
Can you direct me to where I can purchase a more modern tube amp that will
"blow away the ST-70 for $800? Thank you.
Cordially,
west


Send me the $800 and I'll return a ST-70 and a very large fan. ; )

bob H.
Bob H.

Just grab that plate in one hand, the chassis in the other,
and FEEL the power of tube audio!!!
(not literally, of course, just kidding. DON'T DO THAT!)

Would be alot cheaper and would give a the needed chassis.

Just a thought.

JD