[dmac67]

Is the Tung Sol 5881 reissue an appropriate power tube for use in an Onix SP3?  I have heard not to use them in an amp with a solid state rectifier - I have some idea that the SP3 has a solid state rectifier- since there are no rectifier tubes.  Thanks for any help - I am new to tubes.

[HAL]

I used the Tung Sol 5881 reissues in my SP3MKII with good results.  It does have solid state rectification for the power supplies.   Make sure they are a matched quad of tubes.

Would recommend turning the bias all they way down for all four tubes when replacing them so that you can set the bias on the new tubes without stressing them at first use.

[woofersus]

I would also recommend taking a look at Valve Art 350b tubes for the SP3.  I was quite pleased with them when I had an SP3.


Tim Evans
East Street Audio
Onix, Melody, & ACA

[dmac67]

Thanks for both of y'alls replies.  I am setting up a second system based around the SP3.  If I use the Valve Art 350b's, at what value  do I set the bias?  Will they fit in the sockets on the amp?  Will I be able to use the cover (I have a toddler and an inquizative 6 year old)?  Thanks for helping and providing input - like I said, I am new to tubes.

[bunnyma357]

Thanks for both of y'alls replies.  I am setting up a second system based around the SP3.  If I use the Valve Art 350b's, at what value  do I set the bias?  Will they fit in the sockets on the amp?  Will I be able to use the cover (I have a toddler and an inquizative 6 year old)?  Thanks for helping and providing input - like I said, I am new to tubes.

You can't use the cage with the 350B's, also some people have trouble getting them into the sockets and need risers, other SP3's take them no problem - there seems to be some variation in the size of the holes cut in the metal.

Going by memory, since the SP3 threads have vanished from AV123, but I think people were biasing them around 1.45, but with some trying a fairly broad range from 1.25 - 1.6.  (If you have a later SP3/8 with the .4 base bias, you have to do a little math to convert).

A tube I have been happy with both sound and price wise is the coin-base NOS Russian 6P3S-E. I bought mine from eBay form the Ukraine, but some of the domestic tube vendors sell them as well, for a little more money. Also you can use the tube cage with these.

http://shop.ebay.com/?_from=R40&_trksid=p3907.m570.l1313&_nkw=6P3S-E&_sacat=See-All-Categories

In general, the consensus was that rolling the preamp tubes had a bigger impact and to probably start there first.

Although it has far less info than the old threads had, there is still an old SP3 Wiki:

http://onix.pbworks.com/SP3

Jim C

[woofersus]

Ah, I forgot about the cage thing.  Mine didn't have one so I didn't think about it.  Also, I had no trouble with the sockets, but I have no idea how many other people did.  I do know that quite a few people used the 350b's.  I biased them at 1.35v, but as noted above there are some varying opinions on what was best.


Tim Evans
East Street Audio
Onix, Melody, & ACA

[dmac67]

Maybe y'all can tell me if I made a mistake - Two days ago I purchased an open box SP3 described as in good condition but without tubes from AV123 for $169 + $49 for shipping less a $10 credit on file. 

I paid $73 dollars for AV 350b's from Yen Audio and $94.75 for JJ Goldpin 6922's and Mullard reissue 12ax7's from Tube Depot.

Do y'all think $375.75 is a fair deal for this amp with the above compliment of tubes (I didn't include the cost of the NOS Amperex's since they were bought and paid for several years ago)?  I have a feeling people aren't too happy with AV123 as they now stand, but I was willing to take their word that the amp will work perfectly when it arrives.

As for biasing, I purchased a Fluke Model 10 DMM at a pawn shop today.  Even though this model was retired in 2001, it is mint and I felt I couldn't pass it up for $25.  Has anyone here ever tried this meter?

I think I have everything I need to enter the world of tubes.  Is there anything else I'm forgetting?

Thanks again for all the input - It has been incredibly helpful.

[HAL]

According to the specs, the Fluke model 10 has an input impedance of 2K ohms.  It will change slightly the circuit voltage compared to a DMM with high input impedance, like a Fluke 87.    Try setting bias to 1.144VDC to compensate for the meter input impedance.

[dmac67]

Thanks again for the information.  I have no technical knowledge and had no idea that different meters have different input impedences.  Is there a formula I can use to convert values when I am using this meter? 

[woofersus]

Maybe y'all can tell me if I made a mistake - Two days ago I purchased an open box SP3 described as in good condition but without tubes from AV123 for $169 + $49 for shipping less a $10 credit on file. 

I paid $73 dollars for AV 350b's from Yen Audio and $94.75 for JJ Goldpin 6922's and Mullard reissue 12ax7's from Tube Depot.

Do y'all think $375.75 is a fair deal for this amp with the above compliment of tubes (I didn't include the cost of the NOS Amperex's since they were bought and paid for several years ago)?  I have a feeling people aren't too happy with AV123 as they now stand, but I was willing to take their word that the amp will work perfectly when it arrives.

Well, the trust level for AV123 isn't all that high at this point, but assuming it works properly I think $375 total is a great deal for the performance of that amp.  It was an overachiever when it was still $1k years ago.  I don't really know what the going prices for those tubes are (I think I got my 350b's for a little less a couple of years ago, but not a ton) but in terms of absolute value I think it's hard to go wrong with an SP3 at that kind of price.  They sell for more used with those tubes.

Just be aware that AV123 isn't an authorized dealer anymore, so there's no warranty beyond AV123's ability to help you if you every have trouble.


Tim Evans
East Street Audio
Onix, Melody, & ACA

[raindance]

Is the Tung Sol 5881 reissue an appropriate power tube for use in an Onix SP3?  I have heard not to use them in an amp with a solid state rectifier - I have some idea that the SP3 has a solid state rectifier- since there are no rectifier tubes.  Thanks for any help - I am new to tubes.

Don't worry about the SS rectifier in this amp - it is designed for 5881 tubes. That warning is for people who have guitar amps and replace their tube rectifier with a solid state unit to obtain a higher B+ voltage and therefore a bit more power.