[guest1632]

Hi all,

Well, it looks like I've found what preamp I'm gonna use for awhile. However there are a couple of things that I'd like to do.

1. Don't know if this is hype or not, but was thinking about getting some Teflon tube sockets to replace the Ceramic ones. Supposedly, they are suppose to be better at isolating vibrations and such. DIYhifi has the PCB version which I'd need for $10 each for three of them. I'd think the shipping would be more than the sockets.

2. The one thing on this preamp that all of the reviews I've read say, to replace is the 3 position Selector switch. The current one is made out of plastic for the most part and wears out in a short period of time. So if anybody's got any ideas, let me know either here on the board or PM or email me direct.

raybronk@comcast.net


Now my search for the tube preamp isn't over, just found one for a very good price.
Thank you for the help.

Ray

[JoshK]

Ray,

I think your mistaken about the shipping costs.  Diyhifisupply (DHS hereafter) has a flat rate of $7 for parts adding up to less than $100 and free shipping for more than $100.  That isn't really a lot.  Given that they offer the only PCB mountable teflon sockets that I know of and they are less expensive than most others I still think this is your best option.

Regarding the switch, you have a couple options.  If you have room and can swallow the $69 price (would take you over teh $100 hurdle for free shipping, with the addition of a $1 resistor), the Seiden switches that DHS carries are really nice.  They have a smooth feel that most switches don't.  I use these myself and really like them.

[guest1632]

Ray,

I think your mistaken about the shipping costs.  Diyhifisupply (DHS hereafter) has a flat rate of $7 for parts adding up to less than $100 and free shipping for more than $100.  That isn't really a lot.  Given that they offer the only PCB mountable teflon sockets that I know of and they are less expensive than most others I still think this is your best option.

Regarding the switch, you have a couple options.  If you have room and can swallow the $69 price (would take you over teh $100 hurdle for free shipping, with the addition of a $1 resistor), the Seiden switches that DHS carries are really nice.  They have a smooth feel that most switches don't.  I use these myself and really like them.

Hi joshK,

Ah, that would explain the "$7" I see. ok, now we're talking. Do you know if there's any truth about the Teflon sockets?

You said I had a couple options? What else?

Ray

[BradJudy]

I have used a Grayhill series 71 selector switch and liked it.  Not smooth like the one Josh describes, but well built. 

Here's one that would work for $15 (2 poles, adjustable from 2-6 positions) - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH7102-ND

[JoshK]

I believe that teflon sockets have some advantages, so I am using them in the Karna project I am working on because I've already spent so much money on it, I don't want to cheap out on the small things.

What I've read about the teflon sockets from DIY'ers is overwhelmingly positive about the build quality and their pin grip.  (this if for the white $20 ones, I haven't read anything about the blue $10 ones yet, but they seem equally as nice in build.) At first they are supposedly a bit stiff to insert the tube into but they maintain the grip of death on your tube.  That is going to have positives on signal transfer and lessening of microphonics just by itself.   They gents aren't making big claims about the sockets sounding better and I wouldn't really expect to hear a big improvement just from the sockets, although it could happen.  I do think they could have some positive benefits for microphonics because of the material but I don't think they would solve a bad microphonic problem by themselves, but would help. 

Most ceramic sockets are cheaply made.  Sufficient but not much more than that.  The teflon sockets I think are made a step above.  As a DIY'er, I think these are nice things to invest in for your best projects as it makes your projects last. 

[JoshK]

I have used a Grayhill series 71 selector switch and liked it.  Not smooth like the one Josh describes, but well built. 

Here's one that would work for $15 (2 poles, adjustable from 2-6 positions) - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH7102-ND

I like the grayhills too.  I have a couple of them.  Not as nice of feeling, but nice enough.  The Seidens are nicely built all around, the grayhills too.  The Seidens are a bit more like the mercedes benz of switches, with the grayhills the acura. 

[guest1632]

I have used a Grayhill series 71 selector switch and liked it.  Not smooth like the one Josh describes, but well built. 

Here's one that would work for $15 (2 poles, adjustable from 2-6 positions) - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH7102-ND

Hi BradJudy,

That Greyhill switch, with two poles, I presume that then would handle both channels? is the shaft the standard 1/4 inch?

i found a good buy on the Transcendentsound GGP from a guy for $430 unbuilt, and one that has some mods for $675 with the Dact C2 stepped atenuator. Still probably need to in any case, change out the cheap plastic switch.

Ray

[*Scotty*]

Ray, I would recommend this switch. Mouser Part.No. 690-D4G0205N   http://tinyurl.com/23ckv7    http://www.electro-nc.com/rotaryus/d4.pdf         It has a very good build quality and it sounds excellent. It is also easy to solder to with large solder tabs for attaching your wiring to. I would stay away from small closed case switches like the Grayhill. For some reason closed case selector switches reduce the size of reproduced space and restrict dynamics.
Scotty

[BradJudy]

That Greyhill switch, with two poles, I presume that then would handle both channels? is the shaft the standard 1/4 inch?

Yes (assuming single-ended and that you don't care about switching the grounds) and yes 1.4" shaft.  Unfortunately, I got mine at Welbourne for twice the price before I knew that Digikey carried them. 

[guest1632]

Ray, I would recommend this switch. Mouser Part.No. 690-D4G0205N   http://tinyurl.com/23ckv7    http://www.electro-nc.com/rotaryus/d4.pdf         It has a very good build quality and it sounds excellent. It is also easy to solder to with large solder tabs for attaching your wiring to. I would stay away from small closed case switches like the Grayhill. For some reason closed case selector switches reduce the size of reproduced space and restrict dynamics.
Scotty

Thanks for the information.

Ray

[guest1632]

Ray, I would recommend this switch. Mouser Part.No. 690-D4G0205N   http://tinyurl.com/23ckv7    http://www.electro-nc.com/rotaryus/d4.pdf         It has a very good build quality and it sounds excellent. It is also easy to solder to with large solder tabs for attaching your wiring to. I would stay away from small closed case switches like the Grayhill. For some reason closed case selector switches reduce the size of reproduced space and restrict dynamics.
Scotty

Hey Scotty,

What about this mouser number:

105-SR2511F-25NS. 

Ray

[JoshK]

My $.02...

I would get a dual deck 2 pole switch so that you can switch both hot and ground (assuming single ended).  I really just don't like the idea of all the grounds from all the sources being tied together.  Whether or not it matters I don't know, however, I could see, depending on how their grounds are implemented, parrallel paths to ground causing ground loop problems.  If I am going to the trouble of changing a selector, I'd opt for the few bucks more to get one that switches ground as well.  Then you need to make sure the RCA connector is isolated from the case or the additional switching is moot.

Josh

[*Scotty*]

Ray,it is funny that you should ask about that particular switch. I have used that switch in every preamp I have ever built. It is what beat up a Grayhill back in 1986. I figured you were looking for a more expensive switch which is why I recommended the Electroswitch. Somebody I know recently it used in his latest preamp. The Electroswitch has a higher and more robust build quality compared to the Alpha. The Alpha switch is a little delicate if you are soldering very large gauge wire to it. Plus it has phenolic resin decks instead of glass epoxy.  If you don't need a lot of things from Mouser it is cheaper to buy the Alpha switch from Radio Shack.
Scotty

[guest1632]

Ray,it is funny that you should ask about that particular switch. I have used that switch in every preamp I have ever built. It is what beat up a Grayhill back in 1986. I figured you were looking for a more expensive switch which is why I recommended the Electroswitch. Somebody I know recently it used in his latest preamp. The Electroswitch has a higher and more robust build quality compared to the Alpha. The Alpha switch is a little delicate if you are soldering very large gauge wire to it. Plus it has phenolic resin decks instead of glass epoxy.  If you don't need a lot of things from Mouser it is cheaper to buy the Alpha switch from Radio Shack.
Scotty

Actually, Stan Warren suggested that switch. I only need 3 positions. How do you set the amount you need.

Ray

[*Scotty*]

The Electroswitch  has a provision for setting how many switch positions are available, the Alpha switch does not. I never worried about a couple of unused switch positions. If you are building your preamp from a kit be sure to include the GG Preamp Muting Circuit  http://www.transcendentsound.com/timedelay.htm  I would also advise using a 100k DACT pot if its' lowest level of attenuation positions are compatible with your systems' efficiency.
Scotty

[BradJudy]

I would get a dual deck 2 pole switch so that you can switch both hot and ground (assuming single ended).  I really just don't like the idea of all the grounds from all the sources being tied together.  Whether or not it matters I don't know, however, I could see, depending on how their grounds are implemented, parrallel paths to ground causing ground loop problems.  If I am going to the trouble of changing a selector, I'd opt for the few bucks more to get one that switches ground as well.  Then you need to make sure the RCA connector is isolated from the case or the additional switching is moot.

Since every integrated amp, receiver and commercial pre-amp I've looked at links the grounds and doesn't switch them, I wouldn't worry about it.  Even in cases where the grounds are isolated from the chassis, they are generally linked to each other.

[guest1632]

The Electroswitch  has a provision for setting how many switch positions are available, the Alpha switch does not. I never worried about a couple of unused switch positions. If you are building your preamp from a kit be sure to include the GG Preamp Muting Circuit  http://www.transcendentsound.com/timedelay.htm  I would also advise using a 100k DACT pot if its' lowest level of attenuation positions are compatible with your systems' efficiency.
Scotty

Hi Scotty,

So you have some familiarity with the GGP? I'm not sure whether to get his stepped attenuator, or the Goldpoint one. I presume the value is 100K, because his stepped attenuator shows to be 100K.

Do you know if the Selector switch is a single deck or double?

Are there enough traces on the board to have more than just 3 positions?

What are the values of the coupling/output caps?
Ray

[*Scotty*]

Sorry, Ray I only know what I read about GGP, it looks promising. I would contact Bruce Rozenblit with your questions about the kit.
Good luck with your project.
Scotty

[reomi]

Where does one find the blue teflon tube sockets?

I believe that teflon sockets have some advantages, so I am using them in the Karna project I am working on because I've already spent so much money on it, I don't want to cheap out on the small things.

What I've read about the teflon sockets from DIY'ers is overwhelmingly positive about the build quality and their pin grip.  (this if for the white $20 ones, I haven't read anything about the blue $10 ones yet, but they seem equally as nice in build.) At first they are supposedly a bit stiff to insert the tube into but they maintain the grip of death on your tube.  That is going to have positives on signal transfer and lessening of microphonics just by itself.   They gents aren't making big claims about the sockets sounding better and I wouldn't really expect to hear a big improvement just from the sockets, although it could happen.  I do think they could have some positive benefits for microphonics because of the material but I don't think they would solve a bad microphonic problem by themselves, but would help. 

Most ceramic sockets are cheaply made.  Sufficient but not much more than that.  The teflon sockets I think are made a step above.  As a DIY'er, I think these are nice things to invest in for your best projects as it makes your projects last. 

[Gordy]

Where does one find the blue teflon tube sockets?

DIY HiFi Supply... http://www.diyhifisupply.com/diyhs_sockets.htm