EL34s or 807s chooses?
Darrell Whitfield
Hello All!
I'm in the planning stage of my first tube amp (push-pull), I'm trying
to decide which output tubes to use. I have a modded ST-70 and I love
EL34s but I have been reading about 807s and how good
they sound in triode mode. Can anyone make a comparison of these two
tubes? I'm thinking triode 807s vs ultra-linear EL34s. I need about
25-40 watts. Please vote!
Thanks!
Darrell
Vernon H. Brown
Darrell,
As the designer and builder of the amp you don't need to choose, what
you will want to do is experiment. I suggest you compromise and use the
6BG6 instead of the 807 as you then don't have to worry about changing
sockets as you experiment. The 6BG6 is essentially the same tube as the
807 but uses an octal socket. Both should work well with a 5K primary
impedance output transformer so any differences are going to be in the
drive circuit and feedback loop. You didn't mention which circuit
topology you intend to use but the Williamson should accomodate both
output tubes with little modification. "Stand" your output tubes on 10
ohm resistors to measure the current through them and build a flexible
bias supply capable of a wide voltage range and have fun and experiment.
BTW you may not need as much power as you think. The triode connected
807/6BG6 will only give you about 15W.
Best REgards,
Sandy Brown
Scott Pritchard
Isn't the 6K primary and better match for the 807. I have some that
are 6.6K I believe. Then 4K I think is ideal for the EL34 as I remember.
I think a 5K is a sort of a compromise? Does this make a big difference?
I'm thinking of biulding the same amp.
Scott
Max or Paul
Darrell Whitfield wrote:
> Hello All!
>
> I'm in the planning stage of my first tube amp (push-pull), I'm trying
>
> to decide which output tubes to use. I have a modded ST-70 and I love
> EL34s but I have been reading about 807s and how good
> they sound in triode mode. Can anyone make a comparison of these two
> tubes? I'm thinking triode 807s vs ultra-linear EL34s. I need about
> 25-40 watts. Please vote!
>
> Thanks!
>
> Darrell
You're not going to get more than 15 watts or so from PP triode
connected 807s (in class A), so go with the EL34s.
Also, you will need new sockets and top caps for the 807s. To get a
similar sound to the 807s, why not use 5881s or 6L6GCs? After all, the
807 is just a 6L6G with a top cap and a different base.
In my current project, I was faced with exactly the same question as
you. I had some 807s that I wanted to use, but ended up using EL34s
because of the higher, more linear power they can produce.
Hope I have been of some help to you. Email me if you have any
questions,
Max.
Ron
I have to agree totally.
With enough B+, EL34's or E34L's will get approx 30 watts in triode
mode. If you wire the sockets correctly, 6550's or KT88's can also be
used. Of course the Dyna only runs about 410v. For a bit more power,
switch to solid state rectification.
807's sure are pretty though! :-)
Ron
Darrell Whitfield
First of all, I what to thank everyone that responded.
This is a *NEW* amp I'm not modding my ST-70. I was thinking of PPP807 in
triode mode for 30watts, my fault I was not clear. I wanted someone who has
experience with these two tubes that can give me a comparison of the sound
characteristics (EL34 vs 807).
I was thinking of a voltage amp/cathode-coupled phase splitter configuration
like the Mac 230 Williamson is a second. I am leaning towards the
807/6BG6/1625 side since I have one EL34 amp.
Any suggestions on this project are welcome.
Thanks again
Darrell
Andy Moss
Darrell Whitfield wrote:
>
> Hello All!
>
> I'm in the planning stage of my first tube amp (push-pull), I'm trying
> to decide which output tubes to use. I have a modded ST-70 and I love
> EL34s but I have been reading about 807s and how good
> they sound in triode mode. Can anyone make a comparison of these two
> tubes? I'm thinking triode 807s vs ultra-linear EL34s. I need about
> 25-40 watts. Please vote!
The EL34 tubes are better suited to the ST70 due to the low primary
impedance of the A470.
EL34 tubes are true power-pentodes whereas the 807 is a beam-pentode (I
believe).
Besides, everyone knows that power-pentodes *sound* better. 8-)
As an aside, a friend of mine just built a pair of 807 trioded
amplifiers and used the 807 over the 6L6GC 'cuz he needed to run a
higher plate voltage.
Cheers!
engin...@internetmci.comspamnot
> EL34 tubes are true power-pentodes whereas the 807 is a beam-pentode (I
> believe).
>
> Besides, everyone knows that power-pentodes *sound* better. 8-)
I thought an 807 was considered a beam tetrode?
<Or have I spent too much time staring at a lit 450TL?>
Leif
Wilfred
Hi all,
The transformer guys I know advice 6k2 for a pair of UL-connected EL34's.
Wilfred
Vernon H. Brown heeft geschreven in bericht <>Hi Scott,
>
>You are correct, sir. The 5k is a compromise between the 4.3k for the
>EL34 and the 6k for the 807.
Vernon H. Brown
Hi Scott,
You are correct, sir. The 5k is a compromise between the 4.3k for the
EL34 and the 6k for the 807. A negligible compromise IMHO, however.
Perhaps the tranny gurus will have a more elaborate assessment.
Regards,
Sandy Brown
Ned Carlson
Darrell Whitfield <dwh...@swbell.net> wrote:
>
>I was thinking of a voltage amp/cathode-coupled phase splitter configuration
>like the Mac 230 Williamson is a second. I am leaning towards the
>807/6BG6/1625 side since I have one EL34 amp.
6L6-GC will do about the same as 807 for your project.,
within the ratings, the characteristics are the same.
Idea:wire the socket for EL34, provide enough filament
& plate current, and you can try both 6L6-GC,
EL34, or even KT88, KT90 or 6550 if you like,
and decide for yourself.
A liitle bias or cathode resistor
change and you could try 6B4-G, too, if the
plate voltage isn't way high.
"all those people who tell you that you can have as much
fun not drinking as drinking, they're lying to you!"
Harry Caray
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
Email catalogs: email our CataBot: cat...@triodeel.com
Sander deWaal
On Thu, 19 Feb 1998 14:40:58 -0600, Darrell Whitfield
<dwh...@swbell.net> wrote the following:
>First of all, I what to thank everyone that responded.
>
>This is a *NEW* amp I'm not modding my ST-70. I was thinking of PPP807 in
>triode mode for 30watts, my fault I was not clear. I wanted someone who has
>experience with these two tubes that can give me a comparison of the sound
>characteristics (EL34 vs 807).
>
>I was thinking of a voltage amp/cathode-coupled phase splitter configuration
>like the Mac 230 Williamson is a second. I am leaning towards the
>807/6BG6/1625 side since I have one EL34 amp.
>
>Any suggestions on this project are welcome.
Hi Darrell,
I have some experience with 807-based amplifiers.
The dsign that sounded best to me, is a floating-paraphase
phase splitter with ECC83, followed by a 6SN7 driver stage,
driving the grids of the 807's.
There's local feedback from the plates of the 807's to the
cathodes of the 6SN7 halves.
The Ra-a- of the output xformer is 5 Kohms.
The design is PP class A, meaning that there's some 15 watts useful
audio power.
Due to some circuit gadgets, there's only one stage where blocking
caps are used (from plates 6SN7 to grids 807's).
Power supply voltage is about 300 Volts, tube rectified (GZ32), and
choke input. No stabilization, and low capacity (230 uF in total).
Global feedback is 10 dB.
Depending on the quality of the output transformer, frequency response
is flat from 20-100.000 Hz (!).
No additional caps over the feedback resistor, and no
bandwidth-limiting networks are necessary, with my custom wound
transformers.
Other transformers may need a C-R series circuit in parallel to
the plate resistor of the first half of the ECC83, and/or a small cap
over the feedback resistor, to obtain a nice square wave response.
This amp beats virtually every EL 34 based amp, in regards of speed,
detailing, accuracy, and overall imaging.
Soundstage is a little laid back, or "behind" the speakers.
Reversing the absolute phase, pushes it somewhat forward, but not
to the extent of a good SS amp.
I hope this information is of any help to you.
_
Sander deWaal
postm...@pegasus.demon.nl
_______________________________________________
"RAO is like a giant shift register:
garbage in, garbage out."
_______________________________________________
Sander deWaal
On Thu, 19 Feb 1998 23:32:11 +0100, "Wilfred"
<Wilfred....@inter.nl.net> wrote the following:
>Hi all,
>
>The transformer guys I know advice 6k2 for a pair of UL-connected EL34's.
>
>Wilfred
Usually, they recommend 6k6 for UL operation of the EL 34.
This , according to Philips data.
Duncan Munro
On 19 Feb 1998 17:10:14 GMT, sco...@genalex.engr.sgi.com (Scott
Pritchard) wrote:
>Isn't the 6K primary and better match for the 807. I have some that
>are 6.6K I believe. Then 4K I think is ideal for the EL34 as I remember.
>I think a 5K is a sort of a compromise? Does this make a big difference?
>
>I'm thinking of biulding the same amp.
>
>Scott
Hi Scott,
EL34's like a lot lower than 6L6/807 (flame me, but 6L6/807 are both
the same tube internally). At sensible B+ voltages, work on 3500 ohms
for EL34, and 6000 for 6L6/807....
Best Regards,
Duncan
--
Duncan Munro
Check out http://www.duncanamps.simplenet.com/
for Homebrew guitar amps and SPICE models
BOF #023
JLSEM
>
>Scott Pritchard wrote:
>> Isn't the 6K primary and better match for the 807. I have some >>that are
6.6K I believe. Then 4K I think is ideal for the EL34 as >>I remember. I think
a 5K is a sort of a compromise? Does this >>make a big difference? I'm
thinking of biulding the same amp.
>>
>> Scott
>
>Hi Scott,
>
and the 6k for the 807. A negligible compromise >IMHO, however. Perhaps the
tranny gurus will have a more >elaborate assessment.
>
>Regards,
>Sandy Brown
I believe 6.6K p-p would be optimum for the 807 (or any other 6L6 variant)
connected as a beam power amplifier. For triode connection, 10K p-p would be a
better choice (the plate impedence for an 807 in this mode is about 3K). Raise
the transfomer primary impedence for less distortion (and less PO); doing the
opposite will raise both. For BPA and pentode output tubes, optimum load is
found experimentally. Second-order distortion falls then rises as load Z is
increased, third-order distortion and power output both rise as Zp increases.
So, in push-pull amplifiers, you have to decide how much third harmonic
distortion you can stand when choosing your OPT. Of course, applying negative
feedback changes everything....
John
Scott Pritchard
This is my understanding as well. I've picked up 30 807s and feel
like giving them a shot. The 807 Williamsons sound incredable to me.
In article <34ee17c0...@news.demon.co.uk>, postm...@muffy.demon.co.uk (Duncan Munro) writes:
|> Organization: DDS
|> Message-ID: <34ee17c0...@news.demon.co.uk>
|> References: <34EBD6A6...@swbell.net> <34ED36...@capecod.net> <6chp1m$3ra$1...@murrow.corp.sgi.com>
|> Reply-To: postm...@muffy.demon.co.uk
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|>
|> On 19 Feb 1998 17:10:14 GMT, sco...@genalex.engr.sgi.com (Scott
|> Pritchard) wrote:
|>
|> >Isn't the 6K primary and better match for the 807. I have some that
|> >are 6.6K I believe. Then 4K I think is ideal for the EL34 as I remember.
|> >I think a 5K is a sort of a compromise? Does this make a big difference?
|> >
|> >I'm thinking of biulding the same amp.
|> >
|> >Scott
|>
|> Hi Scott,
|>
Josef Schwarz
au...@pegasus.demon.nl wrote:
>>The transformer guys I know advice 6k2 for a pair of UL-connected
>EL34's.
> Usually, they recommend 6k6 for UL operation of the EL 34. This ,
>according to Philips data.
The Telefunken tube pocket book gives these data for EL 34:
B+ ug1eff Ia Ig2 p out dist. Rp(p)
SE class A 265V 8.7V 100mA 11W 10% 2k
PP class AB 375V 21V 2*75/95mA 2*11.5/22.5mA 30W 5% 3.4k
PP class B 800V 23.4V 2*25/91mA 2*3/19mA 100W 5% 11k
PP AB(triode) 400V 22V (Ik)2*65/71mA -------- 16.5W 3% 5k
3.4k is the standard value given in most other German tube manuals I
own, too. The 100W shouldn't be attempted with modern manufacture EL34s,
they won't stand it. Old TFKs and Mullards and RFT (East German) will.
But class B operation is out for hifi anyway.
class B operation will only be of interest to guitarists etc.
Hope this helps,
- Josef
Kenny MacKay, P. Eng.
I've been getting excellent (to my ears) results with SOVtek EL34s and
Hammond 1650F trafos which are 3400 ohms in UL.
kenny
Sander deWaal
On Sun, 22 Feb 1998 17:00:00 +0100,
Josef_...@mk2.maus.sauerland.de (Josef Schwarz) wrote the
following:
>> Usually, they recommend 6k6 for UL operation of the EL 34. This ,
>>according to Philips data.
>
>The Telefunken tube pocket book gives these data for EL 34:
>
> B+ ug1eff Ia Ig2 p out dist. Rp(p)
>SE class A 265V 8.7V 100mA 11W 10% 2k
>
>PP class AB 375V 21V 2*75/95mA 2*11.5/22.5mA 30W 5% 3.4k
>
>PP class B 800V 23.4V 2*25/91mA 2*3/19mA 100W 5% 11k
>
>PP AB(triode) 400V 22V (Ik)2*65/71mA -------- 16.5W 3% 5k
>
>
>3.4k is the standard value given in most other German tube manuals I
>own, too. The 100W shouldn't be attempted with modern manufacture EL34s,
>they won't stand it. Old TFKs and Mullards and RFT (East German) will.
>But class B operation is out for hifi anyway.
>class B operation will only be of interest to guitarists etc.
Josef,
Thanks for your info.
I was talking about UL operation, which is a different animal
altogether.
About the 100 watt class B operation: Sovtek EL34 and Tesla E34L
can do it, if one should want to try that.
Guitarists wouldn't want B operation, either..... :-)
_
Sander deWaal
postm...@pegasus.demon.nl
_______________________________________________
"A Bose FAQ could be rather short: don't buy."
_______________________________________________
Mark Winkler
You've got to go with EL34 ultralinear.
1) Great sounding tube.
2) Excellent match to the driver and OT of the ST70
3) Excellent Russian tubes in current production.
For two 807s in push-pull triode the problem with using the ST70 are:
1) B+ Voltage is too high. 807 in triode can only go about 400 volts
2) Power output will be too low - only 15 watts class AB1 push pull
triode
3) Plate to plate impedence of the 807 at 400V class AB1 is 3000 ohms,
not well matched to the OT
4) The hassle of installing the new socket and plate cap arrangement.
5) Only current manufacturer of the 807 is Chinese (but there are tons
of good 'ol American NOS 807s out there).
Kamaruddin
Max or Paul wrote:
> Darrell Whitfield wrote:
>
> > Hello All!
> I'm thinking triode 807s vs ultra-linear EL34s. I need about
> > 25-40 watts. Please vote!
> >
> > Thanks!
> >
> > Darrell
>
> You're not going to get more than 15 watts or so from PP triode
> connected 807s (in class A), so go with the EL34s.
>
> In my current project, I was faced with exactly the same question as
> you. I had some 807s that I wanted to use, but ended up using EL34s
> because of the higher, more linear power they can produce.
>
>
>
> Max.
I agree with max,
If you want more power use EL34.
6550A is also a good choice. These tubes have plenty of power.
GE6550As are cheap and easy to get.
For god's sake, don't use Chinese tubes to experiment. Unless you want
to experiment how your ST70 blows in your face ;-)
One Eye Jack
Wilfred
Kamaruddin heeft geschreven in bericht <34F400F5...@pacific.net.sg>...
>For god's sake, don't use Chinese tubes to experiment. Unless you want
>to experiment how your ST70 blows in your face ;-)
>
>One Eye Jack
>
>
I guess you haven't even given the GOOD Chinese valves a chance because of
the (sad to say, many) BAD Chinese types.
The Valve Art 6550A is acually very good.
Wilfred
Steve Jones
For how long?
-Steve Jones
MRUKIR
Hello:
I've been using 807's in VTL 140 monoblocks for about 5 years. These
amps run 550 volts on the plates. I have had quite a few different brand tubes
in them for evaluation - Russian, Chinese, and a variety of American ones. The
only ones that had durability problems were the Russian ones. The Chinese ones
have performed very reliably and I would not hesitate to recommend them.
Ned Carlson
On 26 Feb 1998 05:15:53 GMT, mru...@aol.com (MRUKIR) wrote:
> The Chinese ones
>have performed very reliably and I would not hesitate to recommend them.
The idle dissipation in most VTL stuff is very limited..ideal for
Chinese tubes that can't handle lotsa heat.
This is very similar to experiences folks report with Mk3's
and Ampegs: Last a long time if you hold down the
idle bias current.
Try 'em in a Gates transmitter. I give 'em 2 months tops
before they're shot.
Ned Carlson Triode Electronics,2225 W Roscoe St
Chicago, IL, 60618 USA ph 773-871-7459 fax 773-871-7938
"Worldwide Service, Neighborhood Prices" since 1985
Open 12:30 to 8 PM CT, (1830-0200 UTC) 12:30-5 Sat, Closed Wed & Sun
See our web site at http://www.triodeel.com
Text file catalogs: Send a request to our Catalog 'Bot at
cat...@triodeel.com
Wilfred
Steve Jones heeft geschreven in bericht <34F45F...@vcd.hp.com>...
>><<
>> I guess you haven't even given the GOOD Chinese valves a chance because
of
>> the (sad to say, many) BAD Chinese types.
>> The Valve Art 6550A is acually very good.
>
>For how long?
>
>-Steve Jones
Good point, they aren't around for very long yet.
They have been in my amp for about half a year (400V plate to cathode,
70mA). At the moment I'm running in some Svetlana 6550C's (slightly red as
usual). Don't know if they improve during they break in period,but I feel
like going back to Valve Art (so much more musical).
Wilfred
MRUKIR
How do I wire a Gates transmitter to my speakers?
SBench
>
>How do I wire a Gates transmitter to my speakers?
>
>
>
might not load right. If not, you can always use an
antenna tuner. Simply adjust the tuner for minimum VSWR.
Sheldon D. Stokes
In article <19980226161...@ladder02.news.aol.com>, mru...@aol.com
(MRUKIR) wrote:
> How do I wire a Gates transmitter to my speakers?
Ground one speaker wire and hold the other in the air. :)
There's that Gal-AS crystal that can be used as well...
Sheldon
--
Remove SPAM_BE_GONE. from my address to reply to me.
Sander deWaal
On 26 Feb 1998 16:17:47 GMT, mru...@aol.com (MRUKIR) wrote the
following:
>How do I wire a Gates transmitter to my speakers?
Easy.
No wiring required, jjust hook up an antenna, and
the RF field will do the rest.
Howzat for wireless operation?? :-)
Ned Carlson
On 26 Feb 1998 16:17:47 GMT, mru...@aol.com (MRUKIR) wrote:
>How do I wire a Gates transmitter to my speakers?
Get a modulator transformer with an 8 ohm speaker winding.
Ned Carlson
>On 26 Feb 1998 16:17:47 GMT, mru...@aol.com (MRUKIR) wrote:
>
>>How do I wire a Gates transmitter to my speakers?
>
>Get a modulator transformer with an 8 ohm speaker winding.
I should have mentioned that those old RCA theater amps
and old 807 Williamson amps will probably eat Chinese 807's, too.
Duncan Munro
On Fri, 27 Feb 1998 22:32:34 GMT, postm...@triodeel.com (Ned
Carlson) wrote:
>On Fri, 27 Feb 1998 06:13:22 GMT, postm...@triodeel.com (Ned
>Carlson) wrote:
>
>>On 26 Feb 1998 16:17:47 GMT, mru...@aol.com (MRUKIR) wrote:
>>
>>>How do I wire a Gates transmitter to my speakers?
>>
>>Get a modulator transformer with an 8 ohm speaker winding.
>
>I should have mentioned that those old RCA theater amps
>and old 807 Williamson amps will probably eat Chinese 807's, too.
Reminds me of my old man using 807's for his CW transmitter off a 1kV+
plate supply (seriously). I still have all the sets of tubes, RCA and
Westinghouse. Still test OK.
I work on the basis that shit tubes die simply because they are shit
(Chinese etc.). Let's hope they don't take too much other stuff down
with them!!