[smartins]

I've just got a Rudistor RP5.1 from a fellow head-fi member. It came with the stock EH 6922 and a pair of JAN Philips 6922.

I've spend most of the morning reading about tubes including other users recommendations and here are the ones I'm thinking on getting:

Amperex USA 7308 PQ
6H23-EB (no idea of what brand)
6N1P (no idea what brand)

Anyone care to comment about these tubes and possibly other alternatives for the RP5.1?

I'm not looking to spend big bucks on tubes but would like to try a few good ones and decent priced if possible.

Thanks!

 

[edisonwu]

Quote:

Originally Posted by smartins /img/forum/go_quote.gif I've just got a Rudistor RP5.1 from a fellow head-fi member. It came with the stock EH 6922 and a pair of JAN Philips 6922. I've spend most of the morning reading about tubes including other users recommendations and here are the ones I'm thinking on getting: Amperex USA 7308 PQ 6H23-EB (no idea of what brand) 6N1P (no idea what brand) Anyone care to comment about these tubes and possibly other alternatives for the RP5.1? I'm not looking to spend big bucks on tubes but would like to try a few good ones and decent priced if possible. Thanks!

hi, the Amperex USA 7308 PQ is very good sounding tube, but there are different versions of them. Some very nice USA 7308 PQ cost hundreds of dollar.

6H23-EB is a Russian made 6922. The EB suffix means more rugged. Good quality tube for the price.

6N1P is Russian made too and it is actually not really a 6922 even though sometime they are exchangable.

You may also try 6H30, if your amp can handle it (ask manufacturer first).

 

[gundam91]

Don't jump on the tube rolling too fast. Give the amp a listen with both pairs first, then decide what you like and don't like about the sound. Then I'll give you some additional advice. I currently have a pair of Amperex 6922 white label PQ in there. (But that's because I've got a big stash of various 6DJ8/6922/7308 tubes to play with)

 

[Patu]

My favorite tubes were Amperex 6DJ8 White Logo and Mullard 6DJ8.

Amperex was great with HD650, giving it some speed and detail. Mullard was great with W5000 giving some body and weight in to the sound.

Listen to gundam91, he knows what he's talking about.

 

[smartins]

Thanks guys for the advice. I'll give a good listen to both tubes and get back with my findings.

Just one last question, are the Amperex USA 7308 PQ tubes fully compatible with the RP5.1? I seem to find much more of these than the Amperex USA 6922 PQ on eBay and I might grab a pair if I could find ones at a decent price (if it would be compatible of course).

I got reply from Rudistor when I asked about compatibility with 7308 that really didn't helped much.

Quote:

7308 have 6.3 heather but although working are not fully compatible with 6922/E88cc and will require some electrical adjustment in order to work properly If you want to buy new tubes look to for 6922 or E88CC, barely compatible Can be cause of problems

 

[Patu]

Quote:

Originally Posted by smartins /img/forum/go_quote.gif Thanks guys for the advice. I'll give a good listen to both tubes and get back with my findings. Just one last question, are the Amperex USA 7308 PQ tubes fully compatible with the RP5.1? I seem to find much more of these than the Amperex USA 6922 PQ on eBay and I might grab a pair if I could find ones at a decent price (if it would be compatible of course). I got reply from Rudistor when I asked about compatibility with 7308 that really didn't helped much.

I used some 7308's with my RP5.1 and didn't experience any problems. They were Amperex tubes with Orange Globe logo if I remember correctly. You can also use 6DJ8 tubes and ECC88.

 

[bozebuttons]

Quote:

Originally Posted by smartins /img/forum/go_quote.gif Thanks guys for the advice. I'll give a good listen to both tubes and get back with my findings. Just one last question, are the Amperex USA 7308 PQ tubes fully compatible with the RP5.1? I seem to find much more of these than the Amperex USA 6922 PQ on eBay and I might grab a pair if I could find ones at a decent price (if it would be compatible of course). I got reply from Rudistor when I asked about compatibility with 7308 that really didn't helped much.

If Rudi recommends not using the 7308s without modifing the amp.I would stick with his recommendations on the 6922/6dj8.He built the amp & knows
best.

 

[gundam91]

Quote:

Originally Posted by bozebuttons /img/forum/go_quote.gif If Rudi recommends not using the 7308s without modifing the amp.I would stick with his recommendations on the 6922/6dj8.He built the amp & knows best.

Agreed. Although, in general, most gears designed to use 6DJ8/ECC88 can also use 6922/E88CC and 7308/E188CC, there are cases in which this rule does not apply. You had done the right thing and contacted Rudi and get an answer from him directly. I don't think Rudi speaks English, so he might have used some language translation program. I would send him another e-mail to confirm.

I had purchased mine from Rudi, and before he shipped it he changed the internal board and parts and called it the RP5.1cav. Not sure how many of these are out there. But it came with a pair of Philips 6922/E88CC, not 6DJ8/ECC88. I've been using 6922s since it arrived without any issue. I will double check on the technical data on the 6922 and the 7308s.

 

[gundam91]

According to JoeS' article on Audio Asylum's FAQ:

"The 6DJ8 family was originally developed by Amperex. The first tube in the family was the steel pinned 6DJ8 followed by the gold pinned 6922 and 7308. These latter two were premium versions rated as 10,000 hour life tubes. The 6922 was a premium industrial version and the 7308 was the top of the line guaranteed low noise version. Frankly, I’ve measured & listened to a lot of these and there is no correlation between model # and sound quality. Some of the best sounding tubes in this family are 6DJ8s and some of the worst are 6922s & 7308s. So take each tube on it’s own individual merits rather than judging it by its model number or pin material (gold pins do not necessarily = better sound). The Europeans used different model numbers to identify these tubes, by the way. In their numbering system the 6DJ8 was an ECC88, the 6922 was an E88CC and the 7308 was an E188CC."

In all my other gear that uses these tube types, I've never had any problem substituting. It might be good for Rudi to explain why it cannot be used more in detail.

 

[edisonwu]

Quote:

Originally Posted by smartins /img/forum/go_quote.gif Thanks guys for the advice. I'll give a good listen to both tubes and get back with my findings. Just one last question, are the Amperex USA 7308 PQ tubes fully compatible with the RP5.1? I seem to find much more of these than the Amperex USA 6922 PQ on eBay and I might grab a pair if I could find ones at a decent price (if it would be compatible of course). I got reply from Rudistor when I asked about compatibility with 7308 that really didn't helped much.

Heater voltage is the same for E88CC and E188CC.

Let's see the max operating plate voltage:
E88CC: 220V
E188CC: 250V

(6DJ8: 130V)

You can place any E188CC into an E88CC circuit, but you may have problem replce E88CC with E188CC in an E188CC circuit.

 

[gundam91]

Thanks Edisonwu, that was the information I was trying to look for. So as I had mentioned earlier, if the amp is designed with 6DJ8/ECC88, you can sub with 6922/E88CC and 7308/E188CC.

You might want to pass the info to Rudi and see how he responds and post here as I would like to know the answer as well.

 

[smartins]

Thanks guys for all the explanations.

I just checked the reply I got from Rudistor and it seems it was "Hans" from Customer Service that replied to my question, not Rudi himself.

I'll reply back with this information to see what he has to say.