opinions for a good 6v6 output transformer

[The Burwoods]

I would like to replace my output transformers.
The amp is , well this amp
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5712219076&ssPageNam
e=STRK
the fellow changed the 6v6 and rplaced them with 6EZ5 output tubes.When
selecting the output transformers could you use larger ones that ran say 6l6
or 7591's ?Any opinions would be appreciated.

[dre7]

Didna tell ye not to buy this amp? :-)

My advice is junk the 6EZ5s and go to JJ 6V6s - wonderful and cheap tube.
Keep the 5AR4 -- if you need replacements, go Sovtek.

Before you go buying new transformers, be sure to check out the old ones
first as they may be perfectly suitable. They were 6V6 amps originally,
after all?

Transformers will depend on B+ Classic loads for 6V6s are 10,000 ohms @
250v or 8000 ohms @ 285v. I suspect with the 5AR4 you might be pushing
towards the later. IMHO always preferable to load a bit higher -- you get
less power, but also less distortion. If you have to buy transformers, just
go something in the Hammond 1600 series -- 1608 or 1609...probably 35 bucks
each. You might also get away with the 125 Universal Push Pull, ten bucks
less but rated less power. The 125 is the value choice if you decide to go
triode connected.

My Bogens are set up similar - 5AR4 choke input with 6V6s running class A
"psuedo triode" (285v plate a little less on the grid). I really like the
sound of them. Still gonna build a pair of PP 6B4G monos though.

Good luck

dre

The Burwoods <cbur...@mts.net> wrote in message
news:NdjQc.198$bJ2....@news1.mts.net...

[John Stewart]

dre7 wrote:

Didna tell ye not to buy this amp? :-)

My advice is junk the 6EZ5s and go to JJ 6V6s -  wonderful and cheap tube.
Keep the 5AR4 -- if you need replacements, go Sovtek.

Before you go buying new transformers, be sure to check out the old ones
first as they may be perfectly suitable.  They were 6V6 amps originally,
after all?

Transformers will depend on B+  Classic loads for 6V6s are 10,000 ohms @
250v  or 8000 ohms @ 285v.  I suspect with the 5AR4 you might be pushing
towards the later.  IMHO always preferable to load a bit higher -- you get
less power, but also less distortion.

Lower distortion with a higher impedance load is a triode characteristic,
whether in SE or PP. For PP pentodes or Beam tubes, as usual even
order harmonics (2nd, 4th, 6th, Etc) are canceled in a well balanced
stage while odd order harmonics (3rd, 5th, 7th, Etc) are usually reduced
as load impedance is reduced to a point.

That is why you will usually see PP figures for load impedance less than
double that spec'd for the same tube connected SE. The audio power
available also increases.

If you have to buy transformers, just
go something in the Hammond 1600 series -- 1608 or 1609...probably 35 bucks
each.  You might also get away with the 125 Universal Push Pull, ten bucks
less but rated less power.  The 125 is the value choice if you decide to go
triode connected.

Oddly, the 1608 & 1609 are rated at less audio power than the 125E
(10 watts vs 15 watts). However, the 1608 & 1609 offer much tighter
coupling & the possibility to go to Ultralinear operation, something you
can't do with the 125E. Your best all round choice here would be
the Hammond 1608.

Good Luck, John Stewart

[John Stewart]

dre7 wrote:

Didna tell ye not to buy this amp? :-)

My advice is junk the 6EZ5s and go to JJ 6V6s -  wonderful and cheap tube.
Keep the 5AR4 -- if you need replacements, go Sovtek.

If the amp has been retubed using 6EZ5's in place of the 6V6's,
the power transformer will have been stressed.
That is a result of these two factors as follows-
1) the heater current in each tube of 0.8 amp (6EZ5) vs 0.45 amp (6V6)
2) The 6EZ5 has a lower triode mu than the 6V6. That results in a
higher standing plate current at any level of bias.

 
Before you go buying new transformers, be sure to check out the old ones
first as they may be perfectly suitable.  They were 6V6 amps originally,
after all?

Transformers will depend on B+  Classic loads for 6V6s are 10,000 ohms @
250v  or 8000 ohms @ 285v.  I suspect with the 5AR4 you might be pushing
towards the later.  IMHO always preferable to load a bit higher -- you get
less power, but also less distortion.

Lower distortion with a higher impedance load is a triode characteristic,

whether in SE or PP. For PP pentodes or Beam tubes, as usual even
order harmonics (2nd, 4th, 6th, Etc) are canceled in a well balanced
stage while odd order harmonics (3rd, 5th, 7th, Etc) are usually reduced
as load impedance is reduced to a point.

That is why you will usually see PP figures for load impedance less than
double that spec'd for the same tube connected SE. The audio power
available also increases.

If you have to buy transformers, just

go something in the Hammond 1600 series -- 1608 or 1609...probably 35 bucks
each.  You might also get away with the 125 Universal Push Pull, ten bucks
less but rated less power.  The 125 is the value choice if you decide to go
triode connected.

Oddly, the 1608 & 1609 are rated at less audio power than the 125E

(10 watts vs 15 watts). However, the 1608 & 1609 offer much tighter
coupling & the possibility to go to Ultralinear operation, something you
can't do with the 125E. Your best all round choice here would be
the Hammond 1608.

Good Luck, John Stewart

 

My Bogens are set up similar - 5AR4 choke input with 6V6s running class A

[TubeGarden]

Hi RATs!

Just buy a 6.3V transformer with a higher current rating than you need and
don't use the 6.3V filament taps in the original unit.

Check the voltage after hookup and put resistors in series with the transformer
primary to keep it at 6.3V or below.

Fans are for TV sports.

Happy Ears!
Al

Alan J. Marcy
Phoenix, AZ

PWC/mystic/Earhead

[Max Holubitsky]

Why do you want to replace them? The ones in that amp look just fine for doing
what they're doing... replacing an output transformer involves re-designing a
circuit to some extent.