[leftside]

Do you mind posting a very nice picture of the EL12 spez with the adapters on your dac? I want to see if the adapter is nice and worthy of getting. I'm OCD and adapters or anything has to be near perfect. So far I think Woo Audio adapters are ok... or more than ok. Those from china are just so ..... well what can I say. I try to blindfold myself when using them.

Will do. Just got back from a ride, so need to clean the bike and all the muddy gear first (mid winter here). These are white Chinese adapters.

 

[UntilThen]

Will do. Just got back from a ride, so need to clean the bike and all the muddy gear first (mid winter here). These are white Chinese adapters.

You're living dangerously. I just play golf and get @bcowen to drive my golf cart without it going into the lake. That's excitement.

Is this motorbike or bicycle? I mean the rugged kind. I was into those at one time. These days I just do cross country free fall skiing.

 

[LoryWiv]

This is the amp that Mischa wanted to build for me! I insisted on six 5998/6080/6AS7G power tubes, and Mischa said "but that is going to require a ridiculous power supply" I said "yes I know"


Yes TT21 adapters require a wire from base to anode cap. No adapter required for ECC32.


I'm looking forward to using EL12 and spez with this amp! Already have the adapters and am using the tubes in my DAC and preamp.

There is a great seller in the US who I've purchased from before who is selling GEC KT88. I just grabbed a pair as they are a very early version. First version and first year (N) with that glass shape, and the single getter at the top. Later 1950's versions have the 3 getters (two at the side and one at the top). He also has another pair with the single getter at the top and only 2 years newer.
https://www.usaudiomart.com/details/649695132-original-genalex-kt-88s-4

@leftside, thank you so much! His KT88 price seems reasonable if they are in good condition, may go for it myself!

 

[UntilThen]

There are a lot on ebay but just so expensive. I will stick with vanilla EL34 and my Telefunken EL12 spez.

Look at this outrageous price for a quad of GEC KT88.
https://www.ebay.com/itm/Vintage-1960s-Matched-GEC-KT88-Tubes-Quad-Set/284124923433

Found a very nice 6J5 for a reasonable price
https://www.ebay.com/itm/Mullard-6J...rsOtherItemsV2&_trksid=p2047675.c100047.m2108

 

[mordy]

Their most common job as voltage regulators were in the computers of the era.

The thing is that several others reported 5998 tubes arcing and causing damage- one well known designer will not go near them....

 

[UntilThen]

The thing is that several others reported 5998 tubes arcing and causing damage- one well known designer will not go near them....

Several bad experiences with 5998 does not make them bad. Many on the La Figaro 339 and Crack BH thread have use them and are still using them with no issues. My pair have been working like a charm since 2017. Any tube can go bad. 5998 is no exception or more prone.

 

[mordy]

Several bad experiences with 5998 does not make them bad. Many on the La Figaro 339 and Crack BH thread have use them and are still using them with no issues. My pair have been working like a charm since 2017. Any tube can go bad. 5998 is no exception or more prone.

I do have two 5998 tubes and never had a problem - just reporting what I read.
One of my 5998 tubes was made for IBM - if there are lots of 3s and 9s in the numbers on the base of the tube it was made for IBM:

This tube was made by Tung Sol in 1961.

 

[bcowen]

Not everything in life requires tubes.

Yes it does.

 

[UntilThen]

Yes it does.

Tell me about it. For 30 mins, I was trying to get the tubes out of my Mjolnir 2 - without adapters and I couldn't. Mjolnir is Thor's hammer in the mythology. Such is my frustration I want to use Thor's hammer and smash this amp.

But a light bulb moment - I put some scrotch tape and wrap it around the tube and wiggle and pull it up. Relief ! See what tubes does to me.

So now I make sure I use the socket savers as it raise the tubes for my fingers to pull it up. And I found a 5 pack of RCA 6BQ7A / 6BZ7 tubes and these replace the Amperex Orange globes.... I must say it's now no longer Thor's hammer but his crown.

So Mjolnir 2 has replaced Ragnarok who I so savagely sold off. Such is my affinity with tubes that anything that doesn't have tubes will be sold off !

Mjolnir 2 with Yggdrasil - perfect !

Only problem is I need bigger tubes in Mjolnir 2. Can I roll in a EL34 @bcowen ?

 

[bcowen]

Tell me about it. For 30 mins, I was trying to get the tubes out of my Mjolnir 2 - without adapters and I couldn't. Mjolnir is Thor's hammer in the mythology. Such is my frustration I want to use Thor's hammer and smash this amp.

But a light bulb moment - I put some scrotch tape and wrap it around the tube and wiggle and pull it up. Relief ! See what tubes does to me.

So now I make sure I use the socket savers as it raise the tubes for my fingers to pull it up. And I found a 5 pack of RCA 6BQ7A / 6BZ7 tubes and these replace the Amperex Orange globes.... I must say it's now no longer Thor's hammer but his crown.

Just wait until you try and get the socket savers out. LOL!!

If you like the 6BQ7A's, get some Brimars The RCA's will immediately go into storage.

 

[UntilThen]

Just wait until you try and get the socket savers out. LOL!!

If you like the 6BQ7A's, get some Brimars The RCA's will immediately go into storage.

Yes but what about EL34 or KT88. I want to roll those in Mjolnir 2. Might be the biggest Thor's hammer.

 

[bcowen]

Yes but what about EL34 or KT88. I want to roll those in Mjolnir 2. Might be the biggest Thor's hammer.

Why go halfway? Go with an 845 or 211.

 

[Xcalibur255]

I can't wait to see @leftside amp when it is completed. I am a huge fan of the EL34 tube and now that he has a dictionary of info on that tube...this is going to be fun.
I often wonder what the EL34 tube sounds like when being pushed a little bit harder than the 250 volts that mine are...but then I think, the tubes should last longer and there should be less distortion at 250 volts.

Regardless, these tubes sound great and I am excited to see this amp.

My variant will likely operate the EL34 at higher voltages. It's not clear to me at the moment whether or not the KT150 and EL34 are actually sharing a plate voltage or not, but if they are then the EL34 is going to be pushed hard in this design because I wanted the bias points to favor the KT150 which is capable of handling more than the EL34 is.

The thing is that several others reported 5998 tubes arcing and causing damage- one well known designer will not go near them....

Oh I know, I'm one of them. Both Glenn and I lost headphones to arcing 5998s in the same year even. It's very much a legitimate concern with these tubes.

Several bad experiences with 5998 does not make them bad. Many on the La Figaro 339 and Crack BH thread have use them and are still using them with no issues. My pair have been working like a charm since 2017. Any tube can go bad. 5998 is no exception or more prone.

They are severely underbiased in the Darkvoice/LaFigaro amps. I suspect they are in the bottlehead too but I won't assert that because I'm only guessing on that one. The much more conservative operating points make issues less likely. Many times a tube will only misbehave when it is being pushed fairly hard, otherwise the issue lies dormant. The thing about the 5998 is, like with many tubes, it sounds quite different when driven hard vs. driven gently. I personally think the 5998 changes character more than most other tubes in this regard. Those Darkvoice users are hearing something totally different from the 5998 than I am when I use the tube in my GOTL. I don't think the 5998 is a very good sounding tube at conservative operating points, it needs to be pushed for its sound to bloom.

This is dependent on amp circuit and bias design of course.

 

[UntilThen]

They are severely underbiased in the Darkvoice/LaFigaro amps. I suspect they are in the bottlehead too but I won't assert that because I'm only guessing on that one. The much more conservative operating points make issues less likely. Many times a tube will only misbehave when it is being pushed fairly hard, otherwise the issue lies dormant. The thing about the 5998 is, like with many tubes, it sounds quite different when driven hard vs. driven gently. I personally think the 5998 changes character more than most other tubes in this regard. Those Darkvoice users are hearing something totally different from the 5998 than I am when I use the tube in my GOTL. I don't think the 5998 is a very good sounding tube at conservative operating points, it needs to be pushed for its sound to bloom.

I beg to differ. My previous Glenn OTL amp has the 5998 boost switch. In the on position, I don't hear any difference. So I have always left it off. At some point in fact I heard some 'urgency' in the 5998 tubes in the 'on' position. I have heard 5998 in GOTL with the on position and also on La Figaro 339 and Wa22 and they certainly don't sound underperforming on the latter 2 amps. Same 5998 magic even if each amp has it's own sonic signature.

 

[mordy]

Tell me about it. For 30 mins, I was trying to get the tubes out of my Mjolnir 2 - without adapters and I couldn't. Mjolnir is Thor's hammer in the mythology. Such is my frustration I want to use Thor's hammer and smash this amp.

But a light bulb moment - I put some scrotch tape and wrap it around the tube and wiggle and pull it up. Relief ! See what tubes does to me.

So now I make sure I use the socket savers as it raise the tubes for my fingers to pull it up. And I found a 5 pack of RCA 6BQ7A / 6BZ7 tubes and these replace the Amperex Orange globes.... I must say it's now no longer Thor's hammer but his crown.

So Mjolnir 2 has replaced Ragnarok who I so savagely sold off. Such is my affinity with tubes that anything that doesn't have tubes will be sold off !

Mjolnir 2 with Yggdrasil - perfect !

Only problem is I need bigger tubes in Mjolnir 2. Can I roll in a EL34 @bcowen ?

In the past we found this simple solution to pull out recalcitrant tubes - rubber finger grips:

The extra size large fits easily over the 9pin tubes and makes it easy to pull them out and also protects your fingers if the tubes are warm.