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Question for Valve Peeps - 12AU7's

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I recently tube rolled my Prima Luna Evo 400 with a pair of NOS CV4003 Mullards (12AU7) from 1965. I found the sound became, relaxing but thick and muddy - there was characteristics I liked but it lost so much detail over the OEM Prima Luna ones, I ended up the removing them.

Can anyone advise on a tube that had a midway signature between the two? I believe Prima Luna tubes are Chinese made PSVane types. I appreciate the amplifier has been voiced with the OEM ones, and that chopping and changing may be frowned up, but it's something I want to do :) The Mullards were great, but just to much loss of detail. I know not all 'NOS' Mullards are the same, but I don't want to shell out a small fortune again to try a different set!

Would a Brimar valve be more suitable for my requirements maybe?

Thankyou in advance for any thoughts or advice!

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Posted (edited)

I have some Brimar 13D5 tubes which will directly replace the12au7 should you be interested

https://forums.stevehoffman.tv/threads/rolling-tubes-in-a-primaluna-preamp.801872/

Edited by mr.me

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I see from that thread that RFT were recommended for your amp. They certainly work well in my (different) amps and available reasonably priced NOS from eg. Watford Valves or ebay.

Sent from my BLA-L09 using Tapatalk

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I have never bought anything from them.  However, I use their reference guides when looking at flavours of tube.

Have a look here.  Tubeworld.

Euan

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I’ll say it before Rabski does. 😂🤣 How a tube sounds with an amp depends a lot on the amps configuration. You have 2 choices:

1. ask those who have tube rolled with the same PL amp

2. Trial and error

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1 hour ago, tIANcI said:

I’ll say it before Rabski does. 😂🤣 How a tube sounds with an amp depends a lot on the amps configuration. You have 2 choices:

1. ask those who have tube rolled with the same PL amp

2. Trial and error

I couldn't have put it better myself, except I already have :D

Actually, this is a perfect example, because in most applications, CV4003s are the opposite of the somewhat 'syrupy' signature associated with Mullards.

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Gaslight: Try this page: https://www.primaluna-usa.com/tube-rolling

Although Kevin is a full on salesman he does know his valves (tubes). On this page he recommends what tubes work in Prima Luna amps and how they alter the sound and whether they are worth the money. As the advice is specific to PL it is likely to be more relevant than general advice from other amps. Have fun!

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It's a real shame that Upscale Audio don't sell tubes to the UK.

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Posted (edited)

Modern current production Genalux Gold Lion 12AU7s/ecc82 are quite fantastic

I've been very happy with those...  I have a NEW quad if interested... £20 each 

Also NOS Siemens and Halske E82CC, 3 mica 1960s I have 2 (1x matched pair tested) available if interested.. £35 each

these are incredible tubes, tonnes of dynamics and weight lovely airy sound, gives what the Mullard did without the overly stodgey

muddy feeling.... and very quiet.

A very special tube indeed!

Edited by westlower44
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8 hours ago, Gaslight said:

I recently tube rolled my Prima Luna Evo 400 with a pair of NOS CV4003 Mullards (12AU7) from 1965. I found the sound became, relaxing but thick and muddy - there was characteristics I liked but it lost so much detail over the OEM Prima Luna ones, I ended up the removing them.

Can anyone advise on a tube that had a midway signature between the two? I believe Prima Luna tubes are Chinese made PSVane types. I appreciate the amplifier has been voiced with the OEM ones, and that chopping and changing may be frowned up, but it's something I want to do :) The Mullards were great, but just to much loss of detail. I know not all 'NOS' Mullards are the same, but I don't want to shell out a small fortune again to try a different set!

Would a Brimar valve be more suitable for my requirements maybe?

Thankyou in advance for any thoughts or advice!

Hi G,

PrimaLuna valves are made by Shuguang. Psvane are a group of ex-employees of Shuguang ,who left and formed Psvane.

Is there anyone you know who has test gear? A shop. A wee ,one-man operation? Yer 2 Mullards may simply be approaching "end of life". If ye can get them tested then ye can maybe eliminate that problem. I'm surprised that the adaptive autobias hasn't controlled the Mullards. PrimaLuna amps can usually handle almost any valve. I know, I'm using Psvanes, Mullards, RCAs and PrimaLuna's own 12AX7s and 12AU7s. I'd try to get to the bottom of the problem with the Mullards before I'd spend more .

Cheers, Smithy.

PS Ye did use the Mullards in the gain slots ( the 2 centre sockets ?).

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4 minutes ago, locheeboy said:

Hi G,

PrimaLuna valves are made by Shuguang. Psvane are a group of ex-employees of Shuguang ,who left and formed Psvane.

Is there anyone you know who has test gear? A shop. A wee ,one-man operation? Yer 2 Mullards may simply be approaching "end of life". If ye can get them tested then ye can maybe eliminate that problem. I'm surprised that the adaptive autobias hasn't controlled the Mullards. PrimaLuna amps can usually handle almost any valve. I know, I'm using Psvanes, Mullards, RCAs and PrimaLuna's own 12AX7s and 12AU7s. I'd try to get to the bottom of the problem with the Mullards before I'd spend more .

Cheers, Smithy.

PS Ye did use the Mullards in the gain slots ( the 2 centre sockets ?).

The autobias will only set bias for the power valves. There is no way (or need) to change the bias for small signal tubes, but then the 'sound' of different types of the same valve are nothing to do with the bias, as that will be near or identical.

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Posted (edited)

I used ECC802S 12AU7 equivalent TELEFUNKEN tubes in my preamp. I love them. 

Edited by Psilonaught
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6 hours ago, rabski said:

The autobias will only set bias for the power valves. There is no way (or need) to change the bias for small signal tubes, but then the 'sound' of different types of the same valve are nothing to do with the bias, as that will be near or identical.

You’re correct, of course Rabski. I was mixing up my power tubes with my bias tubes. 😎

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Posted (edited)

Another vote for the genalex red lions here. The 12ax7s are superb too.

Adams offer price of £20 per new valve is excellent, I wouldn’t be looking much further than that personally. 

Edited by lordmortlock
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Thank you for all the thoughts and advice.

To address some questions;

I do know of Upscale Audio, I watched enough of his videos before I bought the Prima Luna amplifier, but I have to admit, he does tend to rave about everything as long as he sells it. The new Mullard re-issue tubes have gotten a pretty bad response from users but as he sells them, he raves about them! Still, he dosen't ship tubes outside of the US, so not much I can do there.

I have had Genelax 12AX7's before and I didn't get on with them, they sounded like an atypical Chinese tube to me. I appreciate the 12AX7 will have different characteristics than the 12AU7, and of course the equipment they go into being a huge concern, so I may give them a go.

As pointed out, it can result in a bit of trial and error. At least the main sound is from the two driver tubes, not that costly to keep changing. It it were all five, it would be a bit much.

The Mullards are brand new old stock and have been tested, '4 anodes returned between 2.2 and 2.3mA/v'..apparently. I don't think anything is wrong with them at all, it's just their characteristics, not a fault.

I have the Mullards back in now, and if I could find a hybrid of the two that would be spot on for me!

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